# Adventures in refracting



## jeebsy

Going to use this for general rambling/musings/stupid questions about refracting (please move if another forum is more appropriate)

Made an Aeropress this morning which is traditionally my bete noir of brew methods

Non inverted, paper filter

18.7g Cheleba washed ground at 10 on the 3FE dial

287g water in at 95 degrees

Plunge at 1.30 for around 20 secs

253g coffee out

TDS= 1.4, EY 19.73










This is on the basis non-inverted Aeropress is a drip method....is that right?

Up there with my best ever Aeropress - much clearer flavours than i'd had before - light, lemony and bergamot rather than meh. If anything having the spock is going to help me develop recipes/technique rather than just changing shit all the time.


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## coffeechap

Nice one Jeebsy "the science of coffee" bringing drinks to life


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## Thecatlinux

Nice to see a thread for refactoring, Having a reference point is going to help in such a variable world of coffee.

do you measure temperature each time ?


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## jeebsy

Thecatlinux said:


> Nice to see a thread for refactoring, Having a reference point is going to help in such a variable world of coffee.
> 
> do you measure temperature each time ?


For aeropress yeah, it takes no time and is a bit more reliable than waiting x amount of seconds after the kettle's boiled


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## MWJB

jeebsy said:


> This is on the basis non-inverted Aeropress is a drip method....is that right?


General consensus is that Aeropress should use immersion mode, but if you had used immersion mode your yield would have been 22.5%+, this would normally indicate overextraction (your taste assessment seems to contradict this), but...I have enjoyed Aeropress up to 25% immersion yield.

My guess is that having to drain the coffee through the bed, picking up extra TDS in the process (compared to FP for instance), can push on the range of acceptable tasting yields in immersion mode. Plus steep & release brewers may not fall clearly into 'drip/immersion' as they use elements of both at short steeps.

Use immersion mode, but don't panic if the numbers seem high for a good tasting brew for Aeropress (also Clever).

EDIT: I have used the Aeropress non-inverted as a drip brewer & in drip mode, but when doing so tamped the bed lightly to prevent it breaking up entirely when adding water, so during the plunge I'm aiming to get more water passing through the bed than 'coffee'. From my perspective, as soon as you have stirred the slurry, with all brew water in the Aeropress, it's leaning more to an immersion brew as you will have had significant amount of extraction take place pretty much immediately.


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## garydyke1

MWJB said:


> General consensus is that Aeropress should use immersion mode, but if you had used immersion mode your yield would have been 22.5%+, this would normally indicate overextraction (your taste assessment seems to contradict this), but...I have enjoyed Aeropress up to 25% immersion yield.
> 
> My guess is that having to drain the coffee through the bed, picking up extra TDS in the process (compared to FP for instance), can push on the range of acceptable tasting yields in immersion mode. Plus steep & release brewers may not fall clearly into 'drip/immersion' as they use elements of both at short steeps.
> 
> Use immersion mode, but don't panic if the numbers seem high for a good tasting brew for Aeropress (also Clever).
> 
> EDIT: I have used the Aeropress non-inverted as a drip brewer & in drip mode, but when doing so tamped the bed lightly to prevent it breaking up entirely when adding water, so during the plunge I'm aiming to get more water passing through the bed than 'coffee'. From my perspective, as soon as you have stirred the slurry, with all brew water in the Aeropress, it's leaning more to an immersion brew as you will have had significant amount of extraction take place pretty much immediately.


yeah i would be seeking a TDS of 1.29-1.30% for the aero. 1.40 is quite chewy


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## MWJB

garydyke1 said:


> yeah i would be seeking a TDS of 1.29-1.30% for the aero. 1.40 is quite chewy


Indeed, that's my typical target inverted, but at 25% yield in immersion mode (~55g/l). Water in first helps keep the body down too.


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## jeebsy

I'll dose down slightly and try again tonight. Thanks for your input!


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## charris

Excellent thread, is seems a refractometer is a must these days...


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## DavecUK

Just poked my eyes out with a sharp stick.....


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## The Systemic Kid

charris said:


> Excellent thread, is seems a refractometer is a must these days...


Not a must but definitely useful. Provides really valuable feedback that is objective as opposed to subjective.


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## jeebsy

Made an espresso that came in at 18%. Nasty.

19.6 in 52 out in 25


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## The Systemic Kid

DavecUK said:


> Just poked my eyes out with a sharp stick.....


That's really funny - think a useful analogy for a refractometer being like a torch when fumbling round a darkened room


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## Squarepusher

Does the software have predialled values for different brew methods?

Or do you have to build up the library based upon experience?

I guess from the grid, when you sample the brew you are aiming for the green sweet spot.

if you miss the sweet spot is it easy to work out which variable you need to adjust before you try again?

Looks like a very capable bit of kit?


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## jeebsy

The Systemic Kid said:


> That's really funny - think a useful analogy for a refractometer being like a torch when fumbling round a darkened room







Mike raises that point in this video - it'll help you to train your palate to recognise faults. Right now quite a lot of my brews don't quite turn out right and i can't quite figure out why. I'm hoping this will be a useful tool in diagnosing what's up.


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## urbanbumpkin

jeebsy said:


>


I've got no plans on buying a refractometer. However I think this is a valid point in it being an education tool for working out what under extracted or over extracted tastes like.


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## The Systemic Kid

Squarepusher said:


> Does the software have predialled values for different brew methods?
> 
> Or do you have to build up the library based upon experience


It doesn't. You can save individual tests as recipies and export them if required.


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## AndyS

I've been shocked at how high Aeropress yields can be (based on immersion mode) when using the EK43 grinder. 24%+ and still tasty to my palate!


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## jeebsy

IYesterday's Aeropress dose/water weight was high as had a few more beans left than expected so back to my usual 250ml this morning.

Dropped to 55g/l

13.75g dose, 250ml water, grind 10 on 3FE dial

1m30 brew time then press for about 20

222ml out, 1.15 TDS










Definitely pretty crap by any standards. Not sure why such a minor change affected the TDS so much.

Going to have to make more coffee at the weekend to find out.

And the morning espresso - decided to let it run for longer after yesterday's rancid shot. Better, sweeter, but weak - still got another 4% or so to find.










That was in 25 secs.


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## knightsfield

Hi,

I've been using the Android version of the app.

When I'm in calculator mode and enter the BW value it automatically updates the BEV value. Shouldn't I be able to enter these idenpedently of each other?

Do you get the same behaviour on the version you're using


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## ronsil

See you're enjoying it jeebsy.

Just curious, did my recipes import with your transferred download or was it just a clean new download?


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## Mrboots2u

Your espresso tds is very low. What number are you grinding at ?

Try getting it to 8.5 plus , then you can shorten the shot volume.


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## jeebsy

2.5 on the 3fe dial. Shots are coming too fast but haven't used this bean for espresso before so still dialling in.

Knightsfield - yeah they're linked, you move one and the other changes.

Ron - didn't get your recipes. Seems to have been a totally new installation.


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## fluffles

jeebsy said:


> IYesterday's Aeropress dose/water weight was high as had a few more beans left than expected so back to my usual 250ml this morning.
> 
> Dropped to 55g/l
> 
> 13.75g dose, 250ml water, grind 10 on 3FE dial
> 
> 1m30 brew time then press for about 20
> 
> 222ml out, 1.15 TDS
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Definitely pretty crap by any standards. Not sure why such a minor change affected the TDS so much.


I don't consider myself any sort of expert, but that's about what I would have expected given your recipe there. You dropped the amount of coffee per litre, which would result in a weaker brew. This also means that the water will extract more from the coffee as it has less coffee to work on. This at least makes sense according to my brief filter coffee tuition at Colonna's!

Looks like an interesting bit of kit. How much does it cost?


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## jeebsy

The point was to reduce tds but 5g a litre seems a fairly small change to merit such a proportionately large drop in tds though?


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## Mrboots2u

Perhaps change grind instead of brew weight


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## MWJB

Mrboots2u said:


> Perhaps change grind instead of brew weight


That will drop yield by extracting less, would certainly head more mid box, but Jeebsy seemed to quite like 22.5%. As you see the immersion yields are pretty similar between the 2 brews, a consistent yield is what we're after, just with a less marked drop in %TDS.

Jeebsy, if you're brewing non inverted for a short steep you might want to go a bit higher on ratio, say 60-62g/l (my suggestion for 1.3%TDS, 25% yield & 55g/l takes a bit longer than 1:30). Dropping 10g/l isn't really a minor change.

Set your target yield, then move the slider to give you that yield at the TDS you want. You see that at ~22.5% you were never going to hit 1.3%TDS, you were going to hit ~1.15%TDS...which you did. ;-)


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## jeebsy

Jings. I liked the 22 but would like to try 19ish in case it's better. I'll try your suggestions later, thanks again


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## MWJB

Sure, it's as important to know where you are, so you know which way to move...to get down to 19%, then Bootsy's suggestion of going coarser is the one to take...at the grind you have now, with that consistent technique you are likely to just run up & down (pretty much vertically) the 22-23% yield mark at differing %TDS.


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## fluffles

On a vaguely related note, I noticed in James's World Atlas of Coffee, he suggests a much higher ratio of coffee to water (75g/l) for Aeropress/French press due to it being an immersion brew method. Never heard this recommendation, does that ring true with anyone else? I tried using 16g/250ml this morning as opposed to my usual 14.5g-15g and I must say it tastes a lot better.


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## MWJB

The ratio of coffee to water predominantly sets the strength, as immersion methods typically result in a lower TDS than drip (for the same ratio), a larger dose is required to normalise concentration.

This is because drip brewing yield is based on the strength of the extracted coffee vs dose (what is left behind in the brewer/bed is irrelevant regarding its concentration). Immersion brewing yield is based on the proportion of the dose extracted into the weight of the brew water (as it is assumed that the strength will be largely uniform across the extracted coffee & the liquid retained in the grinds).

You can also brew immersions at lower ratios, but this requires a higher level of extraction (and normally much more time) to get a comparable %TDS. So for typical brew times, updosing corrects this. Aeropress is a quirk and is probably harder to slot into one category than another compared to French press, depending on techniques/method.

It's the extraction yield that drives flavour balance & is the objective, concentration/%TDS has more leeway within reason. %TDS vs mouthfeel perception can vary also depending on the incidence of undissolved solids in the cup...a 1.4% Clever brew might still be fairly 'watery', at 1.4% French press thicker in body.


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## DavecUK

fluffles said:


> On a vaguely related note, I noticed in James's World Atlas of Coffee, he suggests a much higher ratio of coffee to water (75g/l) for Aeropress/French press due to it being an immersion brew method. Never heard this recommendation, does that ring true with anyone else? I tried using 16g/250ml this morning as opposed to my usual 14.5g-15g and I must say it tastes a lot better.


Yes, I have advised friends (over many many yearts) who use my coffee from me and still do, that they should be pretty much doubling (or significantly increasing) the amounts of coffee they use and brewing for less time. Nothing new in James recommendations, as I myself was advised to do this over 20 years ago. I use a dessert spoon per cup (125 ml) and pretty much 2 per mug (250ml).


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## jeebsy

So an Aeropress, modelled on the first one, but with 250ml water and a slightly coarser grind:










Taste: mediocre. Getting chocolate finish and a little fruit but not enough (HB Finca El Pilon)

Might need to just disregard the first one given the higher water weight and start working from scratch...getting there with TDS but extraction still a bit high...coarser again.


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## jeebsy

Anyone know if on the newer ones you have to change it from coffee mode to espresso? Getting some seriously horrendous numbers and hoping that's to blame....


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## ronsil

There is a facility to move between COFFEE ESPRESSO CUPPING modes at top of left hand panel if that is what you mean

None of your pics show the left hand panel


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## The Systemic Kid

Scrolling through menu - right button takes you through espresso to coffee. But it doesn't matter if you've got coffee set when reading espresso - you just move the decimal point - e.g. TDS 1.2 becomes TDS 12% reading espresso on the coffee (pour over/drip) setting.


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## jeebsy

On the refrac itself I mean.

Pressing menu it goes:

Coffee % TDS [Go to set]

Set Zero? [Go to set]

Set Span? [Go to set]

LCD-Light [Go] NO

Language [Go to set]

Ready

And then back to Coffee % TDS [Go to set]


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## The Systemic Kid

Correct. If you inadvertently set the refractometer to 'coffee' it will read 1.2% where, if you'd set it to 'espresso' it would have read 12% with the same sample.


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## jeebsy

Point is though I can't go between coffee and espresso.

Nothwithstanding the above, so if i got 5.72 from an espresso sample it would just mean my espresso was really shit?


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## jeebsy

Just used some of the Rave DSOL as a practice to try and deliberately go over, ground fine, tamped the shit out it, over 12 secs for first drops, 50 secs for 30ish out. It smelt horrible, tasted horrible, was expecting it to be well over but:










The manual says 'later revision instruments have a single coffee tds% scale that covers the entire range of coffee'.

It's reading right through scale so maybe I am just really crap at making coffee.


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## The Systemic Kid

Grinding too fine and tamping the sh*t out of it is going to lead to the puck being too compacted with the result that it won't give up all its solvable solids. Finding the correct balance of grind fineness and the optimum tamp pressure will lead to highest extraction yields. Getting above 20% isn't easy - got to get everything spot on.


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## jeebsy

I was getting 5-6% earlier....have hit double figures so i know the refrac is measuring in both ranges and the problems lies this side of all the machines. Down to me to increase it now.


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## MWJB

jeebsy said:


> Might need to just disregard the first one given the higher water weight and start working from scratch...getting there with TDS but extraction still a bit high...coarser again.


When you go coarser updose too, to shift the junction of the green brew ratio line to intersect the 20% Extraction line at ~1.3%TDS.


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## jeebsy

Wahey!

Grind 11, 250ml in, 1 min 30 steep, 30 sec extraction making 2 mins total


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## Mrboots2u

Foundry LSOL

EK 1.4 ( CD )

4 second pre infusion on the L1

Lovely espresso


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## jeebsy

get out of this thread with your good espresso extractions


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## Mrboots2u

jeebsy said:


> get out of this thread with your good espresso extractions


No....

Lsol

1.4 Callum dial

4 second pre infusion

I label this tasty


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## Mrboots2u

Really opened up the lsol coffee. At high 19 EY get fruit and funk .lovely

At 21 EY plus get sweet fruit cordial. Both lovely ,both different .....


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## jeebsy

Right result wrong working?


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## The Systemic Kid

Why do you think your working is wrong?


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## jeebsy

Tds should ideally be higher?


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## garydyke1

TDS of 7.5% from an 18 into 48 EK shot isn't unusual really mate.


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## jeebsy

That was a down dose with the Kenyan, normally run about a 19.6 dose. Want to try and get closer to double figures this morning.


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## The Systemic Kid

jeebsy said:


> Tds should ideally be higher?


TDS is a function of brewed weight. For a ristretto you would need a TDS of 13% with 18grm dose and a brew weight of 28grms (27.8grm actually) to arrive at extraction yield of 20.9%.


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## jeebsy

Gonna shoot for something like this



> 21g dose, 48g yield, 27 seconds, 9.5% TDS, 21.7% extraction.


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## jeebsy

Little bit drying in the mouth, not the best shot i've had of this


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## MWJB

What happens when you breach 22% at the same ratio?


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## MWJB

HB Othaya Chinga...42g bloom, up to 136g from 0:30, up to 230g from 1:20, up to 324g from 2:10, up to 418g from 3:00. Ended 5:30. Gonna try Gary's suggestion to dose down, go down to 3 pours from 4, see if I can knock off ~0.05% TDS & 1% EY.


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## jeebsy

MWJB said:


> What happens when you breach 22% at the same ratio?


Go finer to do that?


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## MWJB

jeebsy said:


> Go finer to do that?


Yes, finer, but keep the same ratio...that'll shift you up & right, but keep you on the current green brew ratio line. So you should end up ~9%TDS @ 22%EY.

Grinding finer but pulling shorter (moving the green line) will raise TDS, but probably not raise EY.

Just pulling shorter, same grind, will raise TDS & drop EY.


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## MWJB

Sowden brew:


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## Mrboots2u

Don't post mine .....'(


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## MWJB

Mrboots2u said:


> Don't post mine .....'(


Pffft! Nor mine from the other day...lucky only you & I know we're not infallible, perfect, brewbots eh?  ...Ooops...


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## jeebsy

What are you aiming for with the sowden? did you filter?


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## MWJB

jeebsy said:


> What are you aiming for with the sowden? did you filter?


I was aiming for 1.15%TDS @ 23% yield. Sample was syringe filtered prior to refracting, but drink was drunk straight from pot (after pouring off the surface oils & discarding). Water temp in the pot was 92C at the time the coffee was added, 57C after 50mins steep. 0.88 setting on Lido1.


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## Mike mc

Jeebsy I know you use hasbean a lot and was wondering what brew ratio you find works best in the aeropress

I followed the hasbean method but didn't produce a brilliant cup and it doesn't state exactly how much water to use

Any pointers what you find works best?


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## jeebsy

I've only came up with one recipe so far and that was for the foundry beans. 16.5g beans ground at 12 on the ek, 250ml water at 95 degrees, non-inverted, steep for 1.30 then plunge for 30


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## Mike mc

jeebsy said:


> I've only came up with one recipe so far and that was for the foundry beans. 16.5g beans ground at 12 on the ek, 250ml water at 95 degrees, non-inverted, steep for 1.30 then plunge for 30


Cheers mate will try that one later


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## MWJB

HasBean Guatamala Finca San Sebastian Natural Bourbon.

Chemex, 97C start. Bloom 44g @ 40s, 3 POURS: 167g starting at 30s, 296g @ 1:25, 425g at 2:30. Ended 4:23.

Sweet, juicy raisins over baker's choc.


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## jeebsy

Can anyone be bothered to explain what would move the extraction left/right and up/down?

Going to make an idiot's guide for myself.


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## MWJB

To the right & up- grind finer

To the left & down - grind coarser

Just right, finer & more water/less coffee

Just left, coarser & less water/more coffee

Up, staying put re. L/R: More coffee/less water, maybe finer too.

Down, staying put re. L/R: Less coffee/more water, maybe coarser too.

Old style chart, but method is the same...








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## jeebsy

Cheers. Think I'll just print that out instead of trying to make my own graphic using too much company time...


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## jeebsy

The wee chemex is a source of constant annoyance to me so trying to sort out a recipe for it.

21.9g coffee / 350ml water (62.5 g/l)

0.00 - 50g bloom, stir with mini whisk

0.30 - pour 100ml

1.30 - pour 100ml

2.30 - pour 100ml

Bed drained around 3 mins 50.

  Untitled by wjheenan, on Flickr

Flavours are a bit muddy but doesn't feel miles off. Would like to lower TDS and increase EY slightly so go down to 60g/l and grinder slightly finer?


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## garydyke1

try 57g/litre and aim for 1.26-1.28


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## jeebsy

Everything else equal (except go a bit finer presumably)?


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## MWJB

Try dropping the dose to 20.5 to 20.8g (around 59/g/l), same pour regime & 350g. Aim for a 4:10 to 4:30 finish through grind adjustments (finer)?


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## jeebsy

Cheers. This is what Saturday mornings are for.


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## jeebsy

garydyke1 said:


> try 57g/litre and aim for 1.26-1.28



View attachment 12357


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## garydyke1

How's it tasting ?


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## jeebsy

Eating PWO meal just now, will get onto it in a minute.

My readings 'creep' quite a lot, ie first one might be 1.25 then it'll gradually up over the next minute to 1.35, what do you take the reading as? The middle? Or where it settles?


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## Xpenno

I starting following the advice from Gary and have dropped my dose significantly from before and the results have been night and day! I now use 0.054g coffee per ml of brew water added and then tweak from there rather than the 0.06 which is mentioned quite frequently.


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## garydyke1

jeebsy said:


> Eating PWO meal just now, will get onto it in a minute.
> 
> My readings 'creep' quite a lot, ie first one might be 1.25 then it'll gradually up over the next minute to 1.35, what do you take the reading as? The middle? Or where it settles?


How long are you leaving the sample on before pressing the button?


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## garydyke1

Xpenno said:


> I starting following the advice from Gary and have dropped my dose significantly from before and the results have been night and day! I now use 0.054g coffee per ml of brew water added and then tweak from there rather than the 0.06 which is mentioned quite frequently.


this advice is quite EK specific. Lower doses on the Uber grinder/Encore end up being a little bitter and drying at the same parameters , even so I prefer a max of 58-59g/litre on them .

EK is happy 50-55g/litre ; )


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## jeebsy

garydyke1 said:


> How's it tasting ?


Stronger than 1.27. Using this http://www.hasbean.co.uk/products/el-salvador-finca-san-jose-red-washed-bourbon - no cherry


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## jeebsy

garydyke1 said:


> How long are you leaving the sample on before pressing the button?


First one about 15 secs. Could be temperature related


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## garydyke1

jeebsy said:


> First one about 15 secs. Could be temperature related


leave the sample for 60 seconds buddy, temperature needs to equalise


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## garydyke1

jeebsy said:


> Stronger than 1.27. Using this http://www.hasbean.co.uk/products/el-salvador-finca-san-jose-red-washed-bourbon - no cherry


That coffee is a bit old now (comparatively) , the fruit will have died down a touch.

Is your 1.27 actual 1.27 or did it end up >1.30 after several button presses ?


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## jeebsy

When the temperature equalises it's too cold for the refrac to work! Started 1.1 and settled on 1.27 after several readings


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## Xpenno

jeebsy said:


> When the temperature equalises it's too cold for the refrac to work! Started 1.1 and settled on 1.27 after several readings


That's a very big jump, I've not seen it move that much before maybe 0.05 increase.


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## garydyke1

jeebsy said:


> When the temperature equalises it's too cold for the refrac to work! Started 1.1 and settled on 1.27 after several readings


Still got the heating off? its quite warm today outside


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## Xpenno

jeebsy said:


> Stronger than 1.27. Using this http://www.hasbean.co.uk/products/el-salvador-finca-san-jose-red-washed-bourbon - no cherry


What water are you using? Could be muting the fruits and acidity?


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## garydyke1

Here comes the Volvic reply


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## Xpenno

garydyke1 said:


> Here comes the Volvic reply


Lolvic


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## jeebsy

It didn't actually say it was outside temp range even after a minute or two so conditions might be a bit more favourable for taking readings now.

Don't have any problems getting clarity with v60, Spence. Just using good old Scottish tap water, bit soft if anything.


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## jeebsy

IMAG1396 by wjheenan, on Flickr

Lets see how this one works out


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## Xpenno

Ok mate, one thing that could be happening is that because you are no longer boiling your water (as the kettle controls the temp) that your water is not reacting in the same way as it was previously. When you boil water over about 90ppm hardness then it precipitates out and equalises things, it could also alter the pH. Just a thought.

Anyway, presuming water is not the problem then have you tried the Garymex method?

19g (ish) coffee, 350g water, 7 3fe dial. 30g bloom and stir, add the rest in 1 go after 30 seconds and taking around a minute or so.


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## The Systemic Kid

jeebsy said:


> IMAG1396 by wjheenan, on Flickr
> 
> Lets see how this one works out


Is that the temp in your apartment, jeebsy??


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## jeebsy

Xpenno said:


> Ok mate, one thing that could be happening is that because you are no longer boiling your water (as the kettle controls the temp) that your water is not reacting in the same way as it was previously. When you boil water over about 90ppm hardness then it precipitates out and equalises things, it could also alter the pH. Just a thought.
> 
> Anyway, presuming water is not the problem then have you tried the Garymex method?
> 
> 19g (ish) coffee, 350g water, 7 3fe dial. 30g bloom and stir, add the rest in 1 go after 30 seconds and taking around a minute or so.


I've got the small chemex - don't think i'd get 350ml in it at once. It's a pain in the arse, should have just got the normal sized one



The Systemic Kid said:


> Is that the temp in your apartment, jeebsy??


Nah, just the temp the kettle was I switched it on. It's 15 according to the 'thermapen in the air' method


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## Mrboots2u

jeebsy said:


> I've got the small chemex - don't think i'd get 350ml in it at once. It's a pain in the arse, should have just got the normal sized one
> 
> Nah, just the temp the kettle was I switched it on. It's 15 according to the 'thermapen in the air' method


Wave your thermapen in the air , like u just dont.....

Worst rave ever...


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## Mrboots2u

What's the Tds of this pill mate .....


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## Xpenno

jeebsy said:


> I've got the small chemex - don't think i'd get 350ml in it at once. It's a pain in the arse, should have just got the normal sized one


Fair enough mate, wasn't sure how much the little ones could hold.

Good luck!


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## garydyke1

You could do this : -

12.5g - 6 on 3FE dial

250g water total

bloom with 25g water and stir with mini whisk 3 times.

after 30 secs add all the water in one go, stirring with the pour and maintain the max fill level until almost all in , then finish around the outsides with the last 30g or so.

Aim for 3 mins minimum , up to 4 mins


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## jeebsy

Untitled by wjheenan, on Flickr

50g bloom for 30 secs then 100g at 30, 1.30 and 2.30. Bags of milk chocolate, mouth watering sweetness now it's getting close to room temp. THis was 13 on the 3fe dial - going to try Gary minimex method next to compare but going to 6 on the dial will be a bit like this:


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## jeebsy

garydyke1 said:


> You could do this : -
> 
> 12.5g - 6 on 3FE dial
> 
> 250g water total
> 
> bloom with 25g water and stir with mini whisk 3 times.
> 
> after 30 secs add all the water in one go, stirring with the pour and maintain the max fill level until almost all in , then finish around the outsides with the last 30g or so.
> 
> Aim for 3 mins minimum , up to 4 mins


DD took 2.50, 1.11 TDS 21.13 EY. Need to tighten the grind u a fair bit. Not bad cup though.


----------



## fluffles

I'm about to take delivery of radish's r2 mini and have a play with refracting brewed coffee. Could someone offer some advice on what I need and best places to get them. So far I've figured:

A syringe - can I re-use the same one each time?

Disposable pipettes - where's cheapest?

Isopropyl cleaning wipes - do people use these? where's cheapest?

Lint free cloth e.g. KimTech - what do people use for this?

Thanks!


----------



## MWJB

You need Luer lok syringes for the syringe filters (Aeropress, French press, Eva Solo, Cupping, metal filtered drip), you get some of these with the syringe filters, I rinse & reuse the syringes, flush them & rinse with DI water & let dry completely. Not 100% required for paper filtered V60/Chemex/Clever etc. unless you're after ultimate best practice.

Cream Supplies do disposable pipettes.

http://mcldatasolutions.co.uk/kimtech-kimwipes-science-delicate-task-wipers.html?___store=default

I have a bottle of isopropyl alcohol & use that with the Kim Wipes.


----------



## fluffles

MWJB said:


> You need Luer lok syringes for the syringe filters (Aeropress, French press, Eva Solo, Cupping, metal filtered drip), you get some of these with the syringe filters, I rinse & reuse the syringes, flush them & rinse with DI water & let dry completely. Not 100% required for paper filtered V60/Chemex/Clever etc. unless you're after ultimate best practice.
> 
> Cream Supplies do disposable pipettes.
> 
> http://mcldatasolutions.co.uk/kimtech-kimwipes-science-delicate-task-wipers.html?___store=default
> 
> I have a bottle of isopropyl alcohol & use that with the Kim Wipes.


Thanks for the info. Out of interest why do I need that specific syringe? Wouldn't any one do the job?

My plan initially was to not use syringe filters due to the cost. I will be measuring kalita brews (no filtering required) and aeropress (I was going to pass them through another aeropress filter to remove any fines).


----------



## MWJB

If you're not filtering with syringe filters just use the pipettes, or even a clean teaspoon to drop the 4ml sample into a cooling cup, then a clean pipette to drop 0.3ml onto the refractometer prism.

The syringes need the luer lok mechanism to stop the filters flying off when you press the sample through.

I reuse the pipettes for calibrating if they just had DI water in them, you can get dropper bottles for calibration water off Amazon cheap too.

Aeropress often still has gaps around the filter so solids can pass through the gaps, maybe run an Aeropress sample through a V60 filter, or Wave filter?


----------



## The Systemic Kid

Have you used filter papers in place of syringe filters, Mark?


----------



## MWJB

The Systemic Kid said:


> Have you used filter papers in place of syringe filters, Mark?


No, I always syringe filter French press, cupping, Sowden, Aeropress, it was just a suggestion to reduce solids in an Aeropress brew if you didn't have syringe filters.


----------



## garydyke1

Aeropress definitely needs filtering . TDS readings are all over the place otherwise


----------



## fluffles

I'm finding the android app a bit confusing - I don't really get this Design and measure mode stuff.

Anyway, am I right in thinking that for pour over I measure the output beverage weight and for immersion I measure the amount of water added? I've just put in an aeropress recipe and saved it. The saved recipe has an entry "measured beverage: 213g"... but I didn't measure this, I measured the amount I added and it calculated 213g. Have I done something wrong ?


----------



## MWJB

Yes, beverage weight for drip, brew water added for immersion. If you don't add a beverage weight for immersion it'll substitute the preset/default drip LRR, but this makes no difference to the immersion EY.

Design: Select Drip/immersion. Plug in your brew ratio and look at what %TDS the green vector line intersects your EY target, then adjust brew ratio to get the target TDS to fall in line for that EY, keeping EY target constant.


----------



## fluffles

MWJB said:


> Yes, beverage weight for drip, brew water added for immersion. If you don't add a beverage weight for immersion it'll substitute the preset/default drip LRR, but this makes no difference to the immersion EY.
> 
> Design: Select Drip/immersion. Plug in your brew ratio and look at what %TDS the green vector line intersects your EY target, then adjust brew ratio to get the target TDS to fall in line for that EY, keeping EY target constant.


Thanks. When in Design mode it only lets me edit certain values, really frustrating. I find if I just use the padlock thing to unlock then I can enter all values as I want. Why not just use this all the time?


----------



## jeebsy

In design something stays fixed so you can adjust the other parameters to get your target result. If you just move everything about you're not really working towards anything.


----------



## fluffles

jeebsy said:


> In design something stays fixed so you can adjust the other parameters to get your target result. If you just move everything about you're not really working towards anything.


OK - how do I change the thing I'm allowed to change? At the moment I can change dose and TDS but not BW or BEV. What if I wanted to keep the dose the same and use more water. How do I do this?


----------



## MWJB

Can't you select "Dose" as starting value in Presets? (Sorry, I don't have the Android version).


----------



## fluffles

MWJB said:


> Can't you select "Dose" as starting value in Presets? (Sorry, I don't have the Android version).


That's what I've done - seems to work backwards. If I select dose as starting value then I can edit dose but not water. If i select water then I can edit water but not dose.


----------



## MWJB

OK, so select water, then adjust TDS to tie in with desired dose.


----------



## Mrboots2u

There us a padlock on the top of the screen ...is this locked or unlocked


----------



## fluffles

Mrboots2u said:


> There us a padlock on the top of the screen ...is this locked or unlocked


It's locked. Like I said, if I unlock it then the whole Design/Measure thing goes out of the window and I can edit everything. Was wondering what the purpose to the D/M thing is


----------



## Mrboots2u

fluffles said:


> It's locked. Like I said, if I unlock it then the whole Design/Measure thing goes out of the window and I can edit everything. Was wondering what the purpose to the D/M thing is


Can you not unlock it ... I can on the Ipad version


----------



## MWJB

Design shows what you're aiming for, once you have settled on a dose or brew water amount, you select target TDS to give you the missing factor, of the three. Red circle identifies target.

Then you brew & add in your measured values and the blue circle tells you where you landed...if your blue circle is lower & to the left of the red circle grind finer, steep longer. If the blue circle lands above right of the red circle steep shorter/grind coarser.

If you land somewhere where you think things consistently taste better either side of the target EY, change your EY target in presets.

If you like the taste & feel it is at a good EY target, but weak, use a bigger dose/less water and adjust brew parameters like time & grind to stay on the target EY, but hitting a higher TDS.

Maybe tell us what you are trying to plug in/achieve?


----------



## The Systemic Kid

It lets you see where your actual brew is or is not in line with your design.

If you set the design for 20% EY; 1.3% TDS and beverage weight at 443grms, you will see that the red circle is more or less slap band in the middle of the chart if you are using SCAE parameters (green box). If you then enter your actual measured data in the bottom right two boxes (TDS and beverage weight) you will see how far the brew you've made fits the design preference figures. This feature is used by coffee shops where they've set their particular preferences for any method - drip, immersion, espresso and then checking to see how the coffees they are turning out fit with those preferences.


----------



## garydyke1

I had equal frustrations with the Android version.

Just wanna see what my goddam extraction yield was dammit! (lol)


----------



## jeebsy

Is it too simplistic to say dose drives strength and grind drives EY?


----------



## The Systemic Kid

jeebsy said:


> Is it too simplistic to say dose drives strength and grind drives EY?


Over to you Mark @MWJB


----------



## jeebsy

Guessing the short answer is yes


----------



## The Systemic Kid

And no


----------



## MWJB

jeebsy said:


> Is it too simplistic to say dose drives strength and grind drives EY?


Slight tweak: 'brew ratio' drives strength (which I guess is what you meant anyway, as different doses at the same brew ratio will give the same EY at a given TDS) & yes, grind drives EY.

Reasoning here is that if you were trying to hit 1.30%TDS at 20%EY, but actually hit 1.10%TDS @ 17%EY, you'd adjust grind finer to bring up the EY & the TDS falls in accordingly. You could hit 1.3%TDS just by adding more coffee (higher brew ratio), but without changing the grind finer the EY wouldn't rise much & may even drop.

Higher brew ratio & finer grind would make for stronger coffee & at a higher extraction.


----------



## fluffles

Would be interested to hear people's preferences on TDS for brewed coffee. Do you have a value (or range of values) that you like to hit? I know some people lately have been preferring lower TDS than the SCAA/SCAE/NDC recommendations.


----------



## jeebsy

1.3 is about my sweetspot.


----------



## Mrboots2u

You would need to know the EY too though. So for instance might say I tend to like stronger v60 1.35-1.4 TDs but around 20 ey .

I would not like it at 17 ey..

Plus I prefer weaker chemex 1.3 -35 TDs around 19.5 ey than v60

And it will reflect the water and grinder used. Ek 22 plus brewed might taste bad on another set up.


----------



## The Systemic Kid

1.3% drip is around 1.0% immersion.


----------



## MWJB

For me, varies by method...

V60/Melitta 1.3% +/-

Chemex a little lower

Aeropress ~1.2% to 1.35%

French press Sowden 1.11-1.25%, maybe up to 1.3% for a high brew ratio in French press.

Clever steep 1.3% to 1.6% depending on method (lower for steeps with a Swissgold & paper, higher for just paper)

Turkish anywhere up to 2.55% so far...

The important thing is also not to just aim for a TDS, but to balance it against EY, in the French press example I tend to like 52/53g/l at ~1.15% & 23%EY, but for a coffee that struggles to hit that, or has something to offer lower, I'll aim 67g/l, ~1.24%TDS & ~20%EY. Clever with Swissgold & paper may be around 22-23%EY, just paper maybe 24-25%EY. Aim for the EY & fine tune TDS with ratio (sorry if I'm sounding like a broken record).

If you like coffee lower than 1.15%, there's nothing wrong with that, it might even make it easier to pick up on subtle flavours, but 1%TDS at 15%EY will be very different to 1%TDS at 20%EY. Prior to the SCAA box, the US National Coffee Association identified a wider TDS range (1.04% to 1.39%) based on the tastings carried out by their brewing committee. The Nordics have traditionally roasted lighter, hence their box is higher than SCAA.

The boxes aren't an instruction, more a guide/reflection of geographical preference, but also where some folk in the US are roasting lighter, they might relate more to the Nordic box for instance?


----------



## garydyke1

Water plays a huge part in mouthfeel.

My 1.1 TDS with roastery water has a similar mouthfeel to 1.3 TDS with Volvic


----------



## fluffles

garydyke1 said:


> Water plays a huge part in mouthfeel.
> 
> My 1.1 TDS with roastery water has a similar mouthfeel to 1.3 TDS with Volvic


As a matter of interest, what spec is your roastery water?


----------



## fluffles

Thanks for your responses. I find it interesting that you have different preferences for different brew methods. I've often wondered whether there's any real difference between methods. For example, would a paper-filtered aeropress and a v60 brewed to the same TDS and EY taste any different (I wouldn't have thought so)?


----------



## garydyke1

fluffles said:


> As a matter of interest, what spec is your roastery water?


Over 350ppm. Loads of calcium . Really creamy sweet flavours are accentuated. Round and balanced in the mouth.

Not ideal for espresso


----------



## MWJB

fluffles said:


> Thanks for your responses. I find it interesting that you have different preferences for different brew methods. I've often wondered whether there's any real difference between methods. For example, would a paper-filtered aeropress and a v60 brewed to the same TDS and EY taste any different (I wouldn't have thought so)?


You have to consider that the paper filter itself can effect the amount of non-dissolved solids that get into the cup. You can test this yourself easily, brew a French press and decant into a jug, stir to break up any layers and divide the pour, bit by bit, between a cup with no filter, a cup with one type of brewer & filter, another cup with a third filter/brewer type & taste them. This accentuates the effect the filter alone has on the taste, as in a drip brew/brew with a grinds bed the grounds are part of the filtration.

If the V60 & Aeropress brews had the same TDS & EY, then they would have the same TDS & EY (bear in mind same TDS & EY isn't possible using drip & immersion methods), but the filter can still skew taste & mouthfeel (V60 very tight weave, Aeropress not as tight & often gaps around the filter paper that let solids bypass the paper) at the same parameters this may impact your tipping point of preference, one might taste OK (if not stellar) at 23%, the other might be pretty bad at 22%? EY isn't a "taste-o-meter" (e.g. 19% = strawberries, 21% = chocolate), it's a diagnostic based on how much coffee you have washed out of the dose, specific flavours my change within that context, based on coffee age, brew temp, grind distribution, etc.

In terms of actual brewing, I haven't seen a consistent difference in V60, Melitta, Kalitta Wave & V60, in that they produce similar EYs for the same brew method, ratio & time, but may require different grind & pour regime to achieve that (V60 can take finest grind, Chemex can need coarser to save clogging the filter, Kalitta wave on the coarse side as it drains slower for the same brew water mass - you could dial in with the Kalitta & then physically slow down the pour to accommodate the other two).


----------



## fluffles

Made 3 aeropresses with the same bean. Kept the ratio and method the same 15.2g/250g 90C.

1st - 1.25 21.81% - got some nice fruity acidity. Dried my tongue a bit so thought I'd try and extract a bit less.

2nd - 1.27 22.07% - coarsened grind. don't know what happened here but I got a higher EY. tasted a bit dull, less of what i liked in the 1st.

3rd - 1.13 20.01% - i thought this would be better, but its actually the worst of the lot. completely flat and lacking acidity.

Are there peaks and troughs within the 18-22% range? Logic told me if I reigned it in from 21.81% I would get more of the nice acidity but this didn't happen. Maybe if I try and hit 21% I might find a new peak?


----------



## MWJB

For a given brewer & method, I wouldn't expect to get a consistently good flavour all the way from 18-22%.

+0.25%EY isn't going to tell you much that's definitive, don't be afraid to go over 22%EY, (they didn't have Aeropress when the box was identified), but really try a few brews around a target (+/-1%) before making a judgement. You might find a preference between 18-22%, it might be outside that, aim where you consistently get tasty brews across coffees.


----------



## jlarkin

Sorry if this was already mentioned, I watched the Mr. Perger video that mentioned re-using the filters twice for espresso and up to 5 times for brewed (exact words: filter coffee samples). I also thought I'd read somewhere it wasn't a good idea to re-use them but now wasn't sure which is the best approach.


----------



## MWJB

Tim Wendelboe also suggests it's possible to reuse them. VST suggest a new filter for each sample.

A paper filter coffee sample (V60, Chemex, Clever, Kalitta Wave) will have less non dissolved solids to purge, so that might have something to do with Perger's suggestion. For most of us, we're not taking anything like the number of samples that these guys are...I only use a handful of filters a month so just use the once, but don't typically use the syringe filters for Clever, Melitta, V60, Kalitta Wave anyway.


----------



## jlarkin

Do you guys find some of the instructions a bit odd? I did it - but don't see how it helps


----------



## jeebsy

jlarkin said:


> Do you guys find some of the instructions a bit odd? I did it - but don't see how it helps


Did that after a night on the beers, TDS broke the machine


----------



## jeebsy

Cue lots of head scratching and using this thread for reference

  IMAG2016 by wjheenan, on Flickr


----------



## Xpenno

jeebsy said:


> Cue lots of head scratching and using this thread for reference
> 
> IMAG2016 by wjheenan, on Flickr


Has the temp up there gone above freezing then


----------



## Xpenno

MWJB said:


> Slight tweak: 'brew ratio' drives strength (which I guess is what you meant anyway, as different doses at the same brew ratio will give the same EY at a given TDS) & yes, grind drives EY.
> 
> Reasoning here is that if you were trying to hit 1.30%TDS at 20%EY, but actually hit 1.10%TDS @ 17%EY, you'd adjust grind finer to bring up the EY & the TDS falls in accordingly. You could hit 1.3%TDS just by adding more coffee (higher brew ratio), but without changing the grind finer the EY wouldn't rise much & may even drop.
> 
> Higher brew ratio & finer grind would make for stronger coffee & at a higher extraction.


Really nice explanation


----------



## jeebsy

Aeropressing with the new Foundry

15g coffee

250g water giving 220ish out

96 degrees

1 min 30 steep, press for 30

Non-inverted, water in quick, small stir then top on

Grind setting 7 - 1.4ish TDS, 24.3 EY in immersion mode - lacking flavour clarity but not bad

Grind setting 8.5 - 1.18 TDS 20.8 EY in immersion mode - lots of cranberry coming through, pretty tasty, would have thought TDS was higher going by mouthfeel

Want to try and hit 1.3 tomorrow and see how that is, hoping it'll just be a case of going for a grind setting somewhere in the middle


----------



## jeebsy

Xpenno said:


> Really nice explanation


I'm just about to trawl this and the questions on TDS thread to compile an idiot's guide word document


----------



## risky

jeebsy said:


> I'm just about to trawl this and the questions on TDS thread to compile an idiot's guide word document


Look forward to this.


----------



## Xpenno

jeebsy said:


> Aeropressing with the new Foundry
> 
> 15g coffee
> 
> 250g water giving 220ish out
> 
> 96 degrees
> 
> 1 min 30 steep, press for 30
> 
> Non-inverted, water in quick, small stir then top on
> 
> Grind setting 7 - 1.4ish TDS, 24.3 EY in immersion mode - lacking flavour clarity but not bad
> 
> Grind setting 8.5 - 1.18 TDS 20.8 EY in immersion mode - lots of cranberry coming through, pretty tasty, would have thought TDS was higher going by mouthfeel
> 
> Want to try and hit 1.3 tomorrow and see how that is, hoping it'll just be a case of going for a grind setting somewhere in the middle


Try 12-13g, 7 on 3fe dial.

That works well for AP for me.


----------



## garydyke1

Interesting .

Im getting significantly higher TDS/EY with A) straight 5/6/7 BAR shots + coarser grind compared to B) pre infusion with 3/4/5 BAR then ramp to 9/9.5 BAR with a finer grind.

however this isn't quite as straight forward in the cup. Without too much deviation from what I normally do :

14-16% EY via method B) is sweet , focused , clarity ! This is pre hump for sure . I can hit 19-20% by running into lungo ratios and they taste ace too.

The straight low pressure , low flow shots via A) though hitting 20-21% EY are lacking all of the above , its mainly about body, with a compact muddled finish. Suspect if i push through to 22-23% and run longer it will open up again.

Need more time to play : (


----------



## Mrboots2u

Low pressure at 22 plus can be immensely sweet









your looking at 1:2.35-2.4 though I think to get some clarity back over mouthfeel


----------



## MWJB

garydyke1 said:


> 14-16% EY via method B) is sweet , focused , clarity ! This is pre hump for sure .


Sounds like your 15% hump corresponds to the 13% 1st hump with typical grinds.


----------



## Step21

A question on scaling an immersion brew.

If you have made a brew you like and measured the resulting TDS/EY, is the best way to try to replicate this on a different scale (i.e.with either more or less brew water) to try and hit the same TDS by tweaking the brew ratio up or down as necessary or by adjusting grind? Or by other means?


----------



## MWJB

You need to maintain the brew ratio to hit the same TDS & EY, so more coffee & more water (assuming the same method).


----------



## Step21

MWJB said:


> You need to maintain the brew ratio to hit the same TDS & EY, so more coffee & more water (assuming the same method).


Thanks. I thought that i might need to make some allowance for the change in thermal efficiency of the brewer as more/less water is added.


----------



## MWJB

Bigger brews can extract quicker & further than small brews that might be clamped by grind or temperature drop, but also they take longer to drop to a good drinking temp...so time is the thing I'd adjust.


----------



## jeebsy

Untitled by wjheenan, on Flickr

Got this cooling down just now. This week's IMM


----------



## Step21

Looks like you were right on the money there. Did it it taste good ?


----------



## jeebsy

Lovely (once it cooled properly), got the sweet lemons up front and then a really nice sort of toffee finish, not really any nutella though


----------



## garydyke1

jeebsy said:


> Lovely (once it cooled properly), got the sweet lemons up front and then a really nice sort of toffee finish, not really any nutella though


Nutella is in milk 100%.


----------



## jeebsy

MWJB said:


> Reasoning here is that if you were trying to hit 1.30%TDS at 20%EY, but actually hit 1.10%TDS @ 17%EY, you'd adjust grind finer to bring up the EY & the TDS falls in accordingly.


In this case, do you just grind finer and it's OK the brew takes longer or do you compensate somewhere else?


----------



## MWJB

jeebsy said:


> In this case, do you just grind finer and it's OK the brew takes longer or do you compensate somewhere else?


You might find that a 17%EY brew was on the quick side for the weights of coffee & water used? Grinding finer will normally correct the brew time for drip, unless you have very soluble/insoluble coffee. Time alone isn't accurate to nail yield for a given recipe, but it's certainly useful for getting in the ball park. I'd always go by EY & observe time as a sanity check?


----------



## jeebsy

Chemex 18g coffee 340ml water took 4 mins 10ish, 1.16 TDS 315 bev weight, 21.5 EY. It was pretty good (really good at room temp actually) but would like to push up to 24 EY at 1.3 for comparison purposes - so using the design tool I want to drop dose to 17.8 and use 346ml water?


----------



## MWJB

Yes, that looks right for 24% @ 1.3%TDS. Maybe 4:45-ish timewise?


----------



## jeebsy

MWJB said:


> Yes, that looks right for 24% @ 1.3%TDS. Maybe 4:45-ish timewise?


I'll make one when I get home and see how it goes. Ain't half a game of fine margins


----------



## jeebsy

17.8 in, 346 water weight, drained in 4.43 (that's some Zen estimating, @MWJB), 318 out.

Had to pour half in my keepcup and run to tennis (drank it on the way, tasty enough but very 'delicate'), just got home and refracted what was left and it was 1.01 TDS 18.8 EY. Dunno what's going on.


----------



## MWJB

Did you go finer? Maybe break up the pours into more pulses?


----------



## jeebsy

I went a notch finer (16.5 instead of 17.5). Will go a bit finer again tomorrow in case something caused this to be an outlier, not sure why the tds would drop so much


----------



## jlarkin

Does it matter when you refract after making the drink? I know it should be room temp but thought if you left it open too long afterwards that something could start to happen (that's technical speak, sorry if you can't all follow it).


----------



## jeebsy

It was about three hours later, but made sure to stir it thoroughly before refracting.

Assumed it was OK after Boots' talk of offering an international refracting service by post.


----------



## Step21

With regard to getting accurate EY using the Brazen brewer.

1. As it is a kettle some of the input water is being lost in heating the water. For instance when i use it on manual release i'm not getting out what i put in.

2. After brewing when i come to take out the filter i notice water dripping down which hasn't got into the brew. Not a huge amount but a bit tricky to measure.

3. What figure are you using for the Liquid Retained Ratio?

e.g a brew i did earlier (that tasted great). 755ml water in top/ 43.92g coffee in Kalita filter/ temp 203F/ 35sec pre soak - TDS 1.28

Weighed brew output 653g, so a nominal loss of 102g, 102/dose = 2.32 LRR?

If i put 2.3 for drip LRR into VST software and let it calculate using my dose/tds it says i should have a brew output of 668.2g at 94C and EY of 20.29% (changes the LRR to 2.29?)

If i put the actual output EY goes down to 19.83% and LRR is 2.65?

If i assume i'm losing 15ml of brew water and put 740g brew water as input the LRR goes to 2.29 and expected brew output to 653g and EY stays the same at 19.83%

I'm not sure of the best approach for accuracy.


----------



## MWJB

Go by actual measured beverage weight.


----------



## Step21

MWJB said:


> Go by actual measured beverage weight.


What should i use for LRR? Should i subtract something from the input brew water to make allowance for losses?


----------



## garydyke1

Step21 said:


> With regard to getting accurate EY using the Brazen brewer.
> 
> 1. As it is a kettle some of the input water is being lost in heating the water. For instance when i use it on manual release i'm not getting out what i put in.
> 
> 2. After brewing when i come to take out the filter i notice water dripping down which hasn't got into the brew. Not a huge amount but a bit tricky to measure.
> 
> 3. What figure are you using for the Liquid Retained Ratio?
> 
> e.g a brew i did earlier (that tasted great). 755ml water in top/ 43.92g coffee in Kalita filter/ temp 203F/ 35sec pre soak - TDS 1.28
> 
> Weighed brew output 653g, so a nominal loss of 102g, 102/dose = 2.32 LRR?
> 
> If i put 2.3 for drip LRR into VST software and let it calculate using my dose/tds it says i should have a brew output of 668.2g at 94C and EY of 20.29% (changes the LRR to 2.29?)
> 
> If i put the actual output EY goes down to 19.83% and LRR is 2.65?
> 
> If i assume i'm losing 15ml of brew water and put 740g brew water as input the LRR goes to 2.29 and expected brew output to 653g and EY stays the same at 19.83%
> 
> I'm not sure of the best approach for accuracy.


Make sure you're on a level surface.

When the brewer beeps, give it a little shake. You'll release a bit of the residual water and hear it trickle into the carafe


----------



## MWJB

Step21 said:


> What should i use for LRR? Should i subtract something from the input brew water to make allowance for losses?


Measuring brewed weight will generate a LRR figure (in situations where it's inconvenient to measure every brew perhaps establish an average value over 10 brews for that brewer, but I'm always happier measuring rather than relying on a preset value). LR is anything that doesn't land in the cup/carafe, doesn't matter if it's absorbed by the grounds, evaporates, stays trapped in the brewer's boiler, or spills all over the counter because you moved the carafe before the brew was done.


----------



## Step21

garydyke1 said:


> Make sure you're on a level surface.
> 
> When the brewer beeps, give it a little shake. You'll release a bit of the residual water and hear it trickle into the carafe


Thanks. Just checked with a spirit level - absolutely level. Will try the shake!


----------



## Step21

MWJB said:


> Measuring brewed weight will generate a LRR figure (in situations where it's inconvenient to measure every brew perhaps establish an average value over 10 brews for that brewer, but I'm always happier measuring rather than relying on a preset value). LR is anything that doesn't land in the cup/carafe, doesn't matter if it's absorbed by the grounds, evaporates, stays trapped in the brewer's boiler, or spills all over the counter because you moved the carafe before the brew was done.


Thanks. If it were a manual brew and i have a target input i always boil a little more water in the kettle to take account of losing some to evaporation before the pour. Is it because it's not measurable that it is different with a mechanised brew?


----------



## MWJB

Step21 said:


> Thanks. If it were a manual brew and i have a target input i always boil a little more water in the kettle to take account of losing some to evaporation before the pour. Is it because it's not measurable that it is different with a mechanised brew?


Not really, I mean if you do a manual brew at 60g/l and pour 1l into the cone, despite boiling 1.5 or 2l, LRR is still based on the weight you actually pour (evaporation is usually very low in terms of percentage in a drip brew). You might get 2:1 LRR. So, if you then put 1l into an automatic brewer and only 970ml only makes it into the basket, that lost/retained 30ml is added to LRR but your brew ratio (60g/l) stays the same, slightly smaller beverage produced & needs to be a tad stronger to hit equivalent EY at, say, ~2.5LRR. Contact time, basket & brewer design can all affect LRR.

E.g. (just because I have the numbers to hand) my last moka pot brew used 20g coffee, 133g of 'brew' water & produced 80g of finished coffee. Now some of that water never saw the coffee, it was just the motor to drive percolation, but determining how much evaporated, was absorbed by the grounds, seeped out of the screw thread, was displaced by dissolved solids in the brew is impractical to measure to the nth degree, so go by what's more easily observed. The EY (drip/espresso) only 'sees' the 80g beverage & 20g dose.


----------



## fluffles

I remember seeing a VST-like graph which showed how to move around in each direction, e.g. with an arrow pointing towards top right saying "grind finer". Does anyone have this or know where to find it? Thanks


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## jeebsy

View attachment 17857


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## insatiableOne

I had asked about an affordable refractometer before.. got crickets for answers. Not certain what to look for? Not going to spend a few hundred for a good one right now. What could you get away with for espresso??

Quite often with the beans I am currently roasting (ethiopian) have trouble often deciphering if my shots pulled are sour or bitter. → when the end result is close to neutral → my aim point ←

When I get close I'm tired of guessing whether grind finer with less grounds keep same dose, over/under extracted.......my head hurts now.


----------



## Fevmeister




----------



## risky

Found this link http://www.coffeed.com/viewtopic.php?t=2489&f=17

Which discusses using cheap 0-10%TDS refracts designed for sucrose measurement.


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## insatiableOne

Goal!!

Thanks for the link on the brix


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## MWJB

Any refractometer suitable for measuring coffee (reads in coffee %TDS) is hundreds, that is "affordable" compared to bench top models costing thousands/ten thousand.

The trouble with going solely by sour>neutral>bitter is that bitterness can be found in under & over-extracted coffee. If you're dialling in solely by taste, keep going through any early signs of bitterness, to make sure you aren't missing out on a sweet spot just around the corner.

If you're not bothered about real time readings you could dehydrate VST syringe filtered shot samples in the oven (takes hours), using milligram scales. Whatever you use, the VST Coffeetools software is a good idea, to ensure your readings are comparable to other's quoted readings.


----------



## MWJB

risky said:


> Found this link http://www.coffeed.com/viewtopic.php?t=2489&f=17
> 
> Which discusses using cheap 0-10%TDS refracts designed for sucrose measurement.


That's a very old thread & somewhat outdated.


----------



## insatiableOne

Correct the over / under extracted added issue proves to be extremely problematic at times. Seems there are too many variables to screw up, add in a lever then add one more.


----------



## MWJB

insatiableOne said:


> Correct the over / under extracted added issue proves to be extremely problematic at times. Seems there are too many variables to screw up, add in a lever then add one more.


Well, whether you are measuring your EY and know what it is, or not, the number of variables & remedial action remains the same...stick to a ratio, do everything the same, steer flavour via grind adjustment...no joy, adjust ratio & fine tune grind again. The big advantage of knowing your EY is understanding where you are, what's a realistic target & what you might be able to do about it.


----------



## fluffles

Why is the advice to calibrate with distilled water? If you calibrated with your source water would you not get a more accurate picture of the what the coffee has added? With distilled, do you not end up measuring the tds of the water on top of what comes from the coffee? I appreciate this is a very small amount, but I'm wondering why the distilled water is necessary... please enlighten me.


----------



## The Systemic Kid

You calibrate with distilled water because there's nothing in it and as such it becomes your reference point for measuring TDS.


----------



## MWJB

Distilled water has a known refractive index, so it's a datum. The TDS of your brewing water is almost inconsequential (totally insignificant for espresso), unless you are brewing with mega hard water like 400 or 500mg/l (in which case you probably have bigger issues outside of EY). I guess if you know the TDS of your boiled brew water you could deduct that from the reading, but even for a pedant like me, that's hardly worth the bother given the effect on reading.


----------



## risky

Also your source water is very unlikely to be stable anyway. Bottled, tap, it is unlikely it would be the same twice.


----------



## fluffles

MWJB said:


> Distilled water has a known refractive index, so it's a datum.


I had thought all the unit needed was a reference 'starting' point and based it's readings on the relative change. Are you saying that it actually positively needs to know what truly 'empty' is as a starting point?


----------



## garydyke1

Yep , it needs to know zero TDS as a start point.


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## fluffles

thanks!


----------



## dsc

Ok so I've done some refracting recently, trying to see if the connection between TDS and burr gap is linear. First shot was done at 1.02mm burr gap, this was 7.5%, tried this twice and got the same result, so I guess my prep is pretty consistent. Pulled another one, ground at 0.97mm, got 8.2% TDS this time, which gave a TDS delta of 0.7% for 0.05mm drop in burr gap. Went 0.05mm tighter, assuming I'd hit close to 8.9-9.0% TDS, but it went backwards to 7.0%.

I'm guessing you can grind finer to get higher TDS up to a certain point and then stuff gets complicated with the TDS going backwards. Any ideas why? or was it just a cock up on my end again?

T.


----------



## The Systemic Kid

Finer you grind, harder it is for the water to penetrate to optimum efficiency which, in turn, will impact on TDS/EY.


----------



## dsc

So at a super fine level you are simply choking the shot more than "opening" up the beans to water? I guess it's easier to get channeling at that point as well, which explains why the TDS drops rather than keeps increasing.

T.


----------



## jeebsy

dsc said:


> So at a super fine level you are simply choking the shot more than "opening" up the beans to water? I guess it's easier to get channeling at that point as well, which explains why the TDS drops rather than keeps increasing.
> 
> T.


Yeah that seems to be prevailing logic at the moment.


----------



## jlarkin

Nice to see a little of that in action though. I keep meaning to find time to do more checking into this sort of thing


----------



## garydyke1

dsc said:


> Ok so I've done some refracting recently, trying to see if the connection between TDS and burr gap is linear. First shot was done at 1.02mm burr gap, this was 7.5%, tried this twice and got the same result, so I guess my prep is pretty consistent. Pulled another one, ground at 0.97mm, got 8.2% TDS this time, which gave a TDS delta of 0.7% for 0.05mm drop in burr gap. Went 0.05mm tighter, assuming I'd hit close to 8.9-9.0% TDS, but it went backwards to 7.0%.
> 
> I'm guessing you can grind finer to get higher TDS up to a certain point and then stuff gets complicated with the TDS going backwards. Any ideas why? or was it just a cock up on my end again?
> 
> T.


Assuming dose and yield were fixed ?


----------



## dsc

Yup, 16.3g dose (bit random I know, but this was the dose on the first shot so I stuck with it), roughly 34g output, pretty shit extraction rates though based on the TDS values.

T.


----------



## Mrboots2u

dsc said:


> Yup, 16.3g dose (bit random I know, but this was the dose on the first shot so I stuck with it), roughly 34g output, pretty shit extraction rates though based on the TDS values.
> 
> T.


What was the total extraction yield

Are you using coffee tools btw ( and syrignes etc )


----------



## dsc

34g was the total, I use syringes, filter, the whole kaboodle. Extractio rate was around 17-18% from what I remember.

T.


----------



## AndyS

dsc said:


> Ok so I've done some refracting recently, trying to see if the connection between TDS and burr gap is linear. First shot was done at 1.02mm burr gap, this was 7.5%, tried this twice and got the same result, so I guess my prep is pretty consistent. Pulled another one, ground at 0.97mm, got 8.2% TDS this time, which gave a TDS delta of 0.7% for 0.05mm drop in burr gap. Went 0.05mm tighter, assuming I'd hit close to 8.9-9.0% TDS, but it went backwards to 7.0%.
> 
> I'm guessing you can grind finer to get higher TDS up to a certain point and then stuff gets complicated with the TDS going backwards. Any ideas why? or was it just a cock up on my end again?


I'm not sure how many shots you pulled at the second and third adjustment points, but it is dangerous to draw any conclusions from single measurements. Usually three at each point are recommended. And when the grind gets very fine, each detail of prep technique becomes more important, lest one end up with a channeled, low-yielding puck.

That said, the conventional wisdom seems to agree with your guess: if the grind gets too fine, the yield goes down. This idea was discussed on Barista Hustle in the Sept 21-23 time frame.

In that discussion as well as now though, I have to report my contrary result. I've never observed my extraction yields going down as I adjust the EK finer and finer down to the very finest setting. And when I go from the finest setting to slightly coarser ones, my extraction yields always go down.


----------



## jlarkin

AndyS said:


> That said, the conventional wisdom seems to agree with your guess: if the grind gets too fine, the yield goes down. This idea was discussed on Barista Hustle in the Sept 21-23 time frame.
> 
> In that discussion as well as now though, I have to report my contrary result. I've never observed my extraction yields going down as I adjust the EK finer and finer down to the very finest setting. And when I go from the finest setting to slightly coarser ones, my extraction yields always go down.


I wonder if that would make sense if it's "old" coffee burrs. It sounded like they wouldn't go as fine as the newer ones, wondering if that means you'd not hit the bounce back point (so to speak).


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## fluffles

I refracted a brew this morning in the usual way. Paper filtered brew, took a sample and put it in espresso cup to cool (left it for around 30 seconds). Transferred it to the refrac and left it for about 1 minute. Started taking readings which were at 1.34 and then settled down around 1.32. I then left it for 5 minutes and came back, to find it was now reading 1.25.

Which of these readings is the most accurate?


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## jeebsy

Mine tend to go the other way (start low finish high) as the sample cooled and things came to equilibrium so interested in this


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## The Systemic Kid

fluffles said:


> I refracted a brew this morning in the usual way. Paper filtered brew, took a sample and put it in espresso cup to cool (left it for around 30 seconds). Transferred it to the refrac and left it for about 1 minute. Started taking readings which were at 1.34 and then settled down around 1.32. I then left it for 5 minutes and came back, to find it was now reading 1.25.
> 
> Which of these readings is the most accurate?


Good question. My routine is: calibrate the VST with distilled water each morning before using it during the day. Leave the drops of distilled water in the VST's measuring dish to come to room temp while making the first pour over. Pour a small amount of the pour over into a shot glass and leave a minute or so before taking first measurement. Temp of the pour over sample is always above that of the calibrating distilled sample so measurements start low and then climb. I keep measuring until the reading settles. If left for a few minutes then re-read, the reading has dropped. Believe the Mk 3 VST's readings are more stabilised.


----------



## fluffles

jeebsy said:


> Mine tend to go the other way (start low finish high) as the sample cooled and things came to equilibrium so interested in this


Mine always go the other way! Start higher and gradually drop. I do have older hardware though (equivalent of the VST revision 1 I think).


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## jeebsy

Pocket science but maybe to do with stratification?


----------



## AndyS

fluffles said:


> I refracted a brew this morning in the usual way. Paper filtered brew, took a sample and put it in espresso cup to cool (left it for around 30 seconds). Transferred it to the refrac and left it for about 1 minute. Started taking readings which were at 1.34 and then settled down around 1.32. I then left it for 5 minutes and came back, to find it was now reading 1.25.


Typically this kind of variation has two causes:

1. less than adequate filtering

2. sample that hasn't cooled to the same temp as the refractometer prism.

You can test the first possibility by using a syringe filter before you apply the coffee to the prism. Normally a well-filtered brew gives reasonably stable readings for many minutes. The instrument was designed to be used with paper filtered coffee, but some papers and/or techniques leave more particles in suspension than others.

To test the second possibility make sure the espresso cup is at the same room temp as the instrument. Try leaving the sample to cool for a full minute or even two (with a lid to prevent evaporation).

If neither of these strategies gives you readings that are more stable, perhaps your refractometer is damaged.


----------



## MWJB

fluffles said:


> I refracted a brew this morning in the usual way. Paper filtered brew, took a sample and put it in espresso cup to cool (left it for around 30 seconds). Transferred it to the refrac and left it for about 1 minute. Started taking readings which were at 1.34 and then settled down around 1.32. I then left it for 5 minutes and came back, to find it was now reading 1.25.
> 
> Which of these readings is the most accurate?


Out of interest, what was the paper filter? Was the grind unusually fine?

As Jeebsy says, leaving the sample a long time without stirring could lead to stratification.

Following the VST protocol, then taking 10 readings in quick succession, over 6 tests of paper drip brewed coffee, my Lab II was well within stated tolerance (+/- 0.01%TDS for a published tolerance of +/-0.02%TDS).


----------



## fluffles

MWJB said:


> Out of interest, what was the paper filter? Was the grind unusually fine?
> 
> As Jeebsy says, leaving the sample a long time without stirring could lead to stratification.
> 
> Following the VST protocol, then taking 10 readings in quick succession, over 6 tests of paper drip brewed coffee, my Lab II was well within stated tolerance (+/- 0.01%TDS for a published tolerance of +/-0.02%TDS).


It was a Kalita Wave brew, so standard Kalita filter paper (feels similar to to V60).


----------



## MWJB

OK, there shouldn't be any need for additional filtration with a Kalita paper & typical grind. The older Reichart had slightly wider tolerances. As Andy says, I'd perhaps leave the sample cooling in the cup a little longer, before transferring to the sample well?


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## jeebsy

MWJB said:


> Following the VST protocol, then taking 10 readings in quick succession, over 6 tests of paper drip brewed coffee, my Lab II was well within stated tolerance (+/- 0.01%TDS for a published tolerance of +/-0.02%TDS).


Is that taking ten readings of the same sample and getting +/- 0.01% each time, which you repeated with six different brews?


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## MWJB

jeebsy said:


> Is that taking ten readings of the same sample and getting +/- 0.01% each time, which you repeated with six different brews?


No, that's 6 brews, 10 readings of each, typically +/-0.004 averaged Std deviation over 6 sets of ten readings.

Some sets of 10 were +/-0.00 in terms of readings.

The worst set of 10 was +/-0.008 Std deviation (which equates to +/-0.015, or "1.30" to "1.33" over the worst 10 readings).


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## insatiableOne

Bought this for myself → Refractometer with Automatic Temperature Compensation (0-32 Brix)










Now, I am not going to spend $750 0n the VSD so would somone explain how to turn the brix scale into TDS? or is it the same?

I printed off some of jeebsy's charts so would have a reference point to shoot for atleast.


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## knightsfield

You need to multiply the brix by 0.85 to get tds. That is for filtered coffee.


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## Mrboots2u

knightsfield said:


> you need to multiply the brix by 0.85 to get tds. That is for filtered coffee.


 @mwjb


----------



## insatiableOne

knightsfield said:


> You need to multiply the brix by 0.85 to get tds. That is for filtered coffee.


Then would that work for espresso as well?



Mrboots2u said:


> @mwjb


PM him you say?


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## MWJB

The VST might look expensive, but for a refractometer capable of producing an accurate EY for coffee, it takes an instrument at that level. Refractometers have been around and used to evaluate coffee for decades, but it was VST who devised the method for using them for coffee EY measurement. They don't use BRIX refractometers.

There seems little point in using an arbitrary BRIX multiplier to get an approximated TDS reading. Why not record your readings in BRIX?

If your reading accuracy is 0.2%BRIX it's not going to tell you anything useful about coffee in relation to TDS or EY. The aim of the game isn't to use a refractometer specifically, but to get readings & an EY calculation that are meaningful in the established coffee scale. It just so happens that the VST refractometer does this in real time & as accurately as much more lengthy dehydration with careful protocol.


----------



## insatiableOne

MWJB said:


> The VST might look expensive, but for a refractometer capable of producing an accurate EY for coffee, it takes an instrument at that level. Refractometers have been around and used to evaluate coffee for decades, but it was VST who devised the method for using them for coffee EY measurement. They don't use BRIX refractometers.
> 
> There seems little point in using an arbitrary BRIX multiplier to get an approximated TDS reading. Why not record your readings in BRIX?
> 
> If your reading accuracy is 0.2%BRIX it's not going to tell you anything useful about coffee in relation to TDS or EY. The aim of the game isn't to use a refractometer specifically, but to get readings & an EY calculation that are meaningful in the established coffee scale. It just so happens that the VST refractometer does this in real time & as accurately as much more lengthy dehydration with careful protocol.


So then the moral of this story is throw this one that I just bought in the bin, as it is useless for coffee.

Thanks for telling me I bought a paperweight, someone could have mentioned that when I had asked a few pages back.


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## Mrboots2u

Not sure I saw you

Mention you were going to buy one on here tbh, otherwise would have pointed it out .

Did the description online ( where u bought it from ) suggest it measured tds or was applicable for coffee ?

If so send it back , if not then


----------



## insatiableOne

http://www.amazon.com/gp/product/B003H7ILCW?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00#biss-product-description-and-details

Product Description Ade Advanced Optics RHB-32ATC (0-32% Brix scale) Hand Held Refractometer in a CLEAR case. This unit is great for the testing of Fruits, Vegetables and Grasses, Wine or Beer makers and for the maintenance of CNC Coolants (Soluble Oils, Semi-Synthetics, Neo-Synthetics and Synthetics) and Water Soluble Drawing & Stamping Compounds.

When I had searched on Amazon for coffee refractometer this was the first result, coincide with the answer I got when asked 'what is suitable to use" found in this thread here.

If I knew a VST was the only option then never would have purchased one at the moment regardless of price.

Anyone know if amazon will take it back?


----------



## Mrboots2u

insatiableOne said:


> http://www.amazon.com/gp/product/B003H7ILCW?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00#biss-product-description-and-details
> 
> Product Description Ade Advanced Optics RHB-32ATC (0-32% Brix scale) Hand Held Refractometer in a CLEAR case. This unit is great for the testing of Fruits, Vegetables and Grasses, Wine or Beer makers and for the maintenance of CNC Coolants (Soluble Oils, Semi-Synthetics, Neo-Synthetics and Synthetics) and Water Soluble Drawing & Stamping Compounds.
> 
> When I had searched on Amazon for coffee refractometer this was the first result, coincide with the answer I got when asked 'what is suitable to use" found in this thread here.
> 
> If I knew a VST was the only option then never would have purchased one at the moment regardless of price.
> 
> Anyone know if amazon will take it back?


Should do just blag it ... Hey if we get a 50 quid one to work we would all have em ...


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## risky

If it was bought off amazon you can return it for any reason under the distance selling regs, but if you say you searched for coffee refractometer and they listed that in the results im sure they won't argue.


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## Phil104

Unless you make a habit of returning things to Amazon (there was a recent story about them banning customers who were frequently returning items) they should accept a return. I sent a grinder back on the basis that it was no longer required (or something like that from their pick list). I had bought it for my son who in the meantime had got something bigger and better.


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## insatiableOne

Never returned anything from them, purchase from them all the time. Even from Amazon/UK, {gets my card shut down} unless I call the bank first.

Suppose I should have signed up for the free shipping on returns. Have Prime.

Well live & learn.

Good thing have knowlegeable folk on here not wanting to steer me wrong.

Thanks all!!


----------



## GlennV

I'm a great fan of the VST kit and use both the baskets and their refractometer. However, I think it should be pointed out that tds~0.85xBrix is not simply an arbitrary multiplier; it is based on dehydration experiments and attributed to Randy Pope of Bunn in a post by Alan Adler (the inventor of the aeropress) in Jan 2006, which predates the ExtractMoJo release (and is properly referenced by them - there's nothing controversial here):

http://coffeegeek.com/forums/coffee/machines/203992

Personally, I still find an optical brix refractometer quite useful, and sometimes use mine alongside a VST refractometer as a sanity check (you get to see an entire image rather than a single number).


----------



## MWJB

GlennV said:


> I'm a great fan of the VST kit and use both the baskets and their refractometer. However, I think it should be pointed out that tds~0.85xBrix is not simply an arbitrary multiplier; it is based on dehydration experiments and attributed to Randy Pope of Bunn.


These posts that cite it are all rather old & outdated. Alan Adler has more recently posted that he uses a VST refractometer.


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## risky

If it's useable at all I'm interested as I have one in the house, however it's designed for checking the salinity of aquarium water so probably isn't the correct range?


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## MWJB

"Useable" really means giving a reading that equates to a meaningful range of extraction yield, it won't do this.


----------



## Rob1

ARISE! ARISE! ARIIIIISE!

To bring a topic back from the dead.

I've got myself an Atago BX/TDS direct from Atago via amazon for £330. I thought it was about time.

I'm not buying syringe filters. Or syringes. I am open to making a 'paperfuge' to separate out oils and solids from a sample in a little 2ml tube that'll be plenty to give enough samples to refract for any brew method but I haven't gone down that route yet. There are some interesting views on refracting espresso/filtering samples. VST obviously think you should filter them to eliminate noise but the filters themselves actually alter readings of distilled water (something socratic cover). Atago have the view that a filtered sample is not representative of what you drink because it's been filtered, which I understand, but I also understand the opposite POV that you want to eliminate suspended fines and measure only dissolved solids...

Anyway I refracted my first espresso earlier. A low flow rate pre-infusion that saw the pressure begin to rise around 16 seconds, up to full pressure then a slow decline until the pressure went down to 0 and I let it trickle without flow to the target yield of 40.5g (flow was about 1g/s at the end). Total shot time was 36 seconds. It wasn't the best shot I've had of this coffee but it wasn't bad in any way.

Data in the image. The manual recommended stirring oily samples while they are being read, I only did this once on the first sample highlighted in red. All other measures three readings taken from different samples of the same espresso.


----------



## MediumRoastSteam

Rob1 said:


> ARISE! ARISE! ARIIIIISE!
> 
> To bring a topic back from the dead.
> 
> I've got myself an Atago BX/TDS direct from Atago via amazon for £330. I thought it was about time.
> 
> I'm not buying syringe filters. Or syringes. I am open to making a 'paperfuge' to separate out oils and solids from a sample in a little 2ml tube that'll be plenty to give enough samples to refract for any brew method but I haven't gone down that route yet. There are some interesting views on refracting espresso/filtering samples. VST obviously think you should filter them to eliminate noise but the filters themselves actually alter readings of distilled water (something socratic cover). Atago have the view that a filtered sample is not representative of what you drink because it's been filtered, which I understand, but I also understand the opposite POV that you want to eliminate suspended fines and measure only dissolved solids...
> 
> Anyway I refracted my first espresso earlier. A low flow rate pre-infusion that saw the pressure begin to rise around 16 seconds, up to full pressure then a slow decline until the pressure went down to 0 and I let it trickle without flow to the target yield of 40.5g (flow was about 1g/s at the end). Total shot time was 36 seconds. It wasn't the best shot I've had of this coffee but it wasn't bad in any way.
> 
> Data in the image. The manual recommended stirring oily samples while they are being read, I only did this once on the first sample highlighted in red. All other measures three readings taken from different samples of the same espresso.
> 
> View attachment 45401


 Ok. That's great. But I don't know what I'm looking at! 😂

I get: date time, TDS, and temp. 
I don't understand what Brix is. And, I know that the EY (Extraction Yield?) is good when it's around 22 or something? Would be great if you could clarify that. Thank you! 👍

ps: https://en.wikipedia.org/wiki/Glitch_(TV_series) 😂😂😂😂


----------



## Rob1

MediumRoastSteam said:


> Ok. That's great. But I don't know what I'm looking at! 😂
> 
> I get: date time, TDS, and temp.
> I don't understand what Brix is. And, I know that the EY (Extraction Yield?) is good when it's around 22 or something? Would be great if you could clarify that. Thank you! 👍
> 
> ps: https://en.wikipedia.org/wiki/Glitch_(TV_series) 😂😂😂😂


 A normal EY would be about 19-24% according to this table. I've heard 18-22% before https://coffeeadastra.com/2019/02/17/measuring-and-reporting-extraction-yields/

Brix is a measurement of sugar.


----------



## MWJB

Rob1 said:


> I'm not buying syringe filters. Or syringes. I am open to making a 'paperfuge' to separate out oils and solids from a sample in a little 2ml tube that'll be plenty to give enough samples to refract for any brew method but I haven't gone down that route yet. There are some interesting views on refracting espresso/filtering samples. VST obviously think you should filter them to eliminate noise but the filters themselves actually alter readings of distilled water (something socratic cover). Atago have the view that a filtered sample is not representative of what you drink because it's been filtered, which I understand, but I also understand the opposite POV that you want to eliminate suspended fines and measure only dissolved solids...


 The refractometer works on the light passing through liquid & the liquid bending the light. If the liquid has solids suspended in it then it throws the reading off. Solids are not counted towards extraction yield anyway. Yes you drink a drink with some non-dissolved solids but VST didn't invent the concept of EY, it already existed and is based on filtered samples & always has been. Non dissolved solids are not an indicator of brew efficiency, just a rough guide to grind (more for finer grinds) & you know the grind setting when you start brewing.

VST invented the protocol of correlating refractometer readings in coffee TDS against their dehydration results. Atago don't really have a view on this, they actually say expect your reading to be high, but it won't be consistent. The 3 studies by Socratic gave 3 different outcomes, which suggests poor protocol/changes in protocol from one test to the next.

If you don't want to filter, that's fine, but your readings won't be comparable with unfiltered readings. This is also true of filter coffee, especially at very fine grinds (coarser grinds seem OK with just paper filtering, unless with an Aeropress). I'm currently filtering my fine ground filter brew samples and I see 0.12 to 0.15%TDS difference in readings, this is significant and will produce too much noise to be useful. I don't recommend the Atago for filter coffee, especially not without filtering with a syringe (£1.60 a pop right now).

18-22%EY was determined by consumer research carried out by Midwest Research Institute, using filter brewers & known grind sizes & distribution characteristics. This was a big, landmark survey, the one that really led the way. The NCA had a slightly diifferent range previously (17.5-21.2%, also with filter coffee) determined by coffee professionals. At the end of the day you might see 15-25% with espresso, depending on grinder (but a much narrower range for a specific grinder) and the coffee might taste perfectly good.

I tend to find my readings fall +/-10% (e.g. 17+/- 1.7%, or 21+/-2.1%) for a given grinder & brew method, <5% of brews might still fall outside this & be absolutely fine. If you're seeing +/-4 or 5% in EY (for a given scenario), something is likely way off. EY is not & never has been a score of taste (you can extract any coffee to a given range, if it's crap coffee, the cup will still be crap), it is a guide to brew efficiency & consistency, at certain ranges EY correlates to ranges of balance in the big picture (the target represents what you see for a large range of origins, not that all coffees will taste good above 18%EY or under 22%EY.

Individual coffees might only vary by <+/-0.5%EY for a given method. So you need to tie readings to a roast/bag. Also it is vital to also have a taste score.

Origin is the biggest factor in EY (with grind & ratio being constant). Whether you view the range as 15-19, 18-22, 17-21% there can still be acceptable tasting coffee below this (ristrettos & coarse grind, high dosed Aeropress for example) so I'd keep separate records for different brewers & substantially different methods.

I wouldn't average the samples from 1 beverage, take a few readings after leaving it in the refractometer for at least 30s to let it stabilise and record the last readings/when the reading stabilises (say 3 readings the same).


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## MWJB

Rob1 said:


> Data in the image. The manual recommended stirring oily samples while they are being read, I only did this once on the first sample highlighted in red. All other measures three readings taken from different samples of the same espresso.
> 
> View attachment 45401


 Re-reading this, "different samples of the same espresso".

Does this mean that all readings came from the same, single beverage? If so, stir the shot straight after brewing, let it sit for minute, suck up a sample from under the crema (say 1cm deep), but not from the silty bottom of the cup (so using similar shaped vessels for sampled shots would be handy) & try to do it the same way each time. Consistency of protocol is more important than specific reading you get.

To get a 1.6%EY span with the same bag of coffee would normally mean a change in grind, or output. Or a different coffee at same grind & output. I wouldn't expect to a swing of this size with the same bag of coffee (let alone same cup), grind & output


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## Rob1

MWJB said:


> Re-reading this, "different samples of the same espresso".
> 
> Does this mean that all readings came from the same, single beverage? If so, stir the shot straight after brewing, let it sit for minute, suck up a sample from under the crema (say 1cm deep), but not from the silty bottom of the cup (so using similar shaped vessels for sampled shots would be handy) & try to do it the same way each time. Consistency of protocol is more important than specific reading you get.
> 
> To get a 1.6%EY span with the same bag of coffee would normally mean a change in grind, or output. Or a different coffee at same grind & output. I wouldn't expect to a swing of this size with the same bag of coffee (let alone same cup), grind & output


 It was the same cup, and I used a spoon. I was just messing about with it really. I used a Pipette the other day in the way you described and got much more consistent readings. I'll make a paperfuge and spin a small sample by hand to separate oils and solids next time, it's not as good as filtering but it's very close. The only alternative is to buy some cheap syringe filters of 0.2-0.4um from amazon or ebay because I'm not paying for the VST branded ones, I'd rather avoid the waste if not also the cost.


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## MWJB

Rob1 said:


> It was the same cup, and I used a spoon. I was just messing about with it really. I used a Pipette the other day in the way you described and got much more consistent readings. I'll make a paperfuge and spin a small sample by hand to separate oils and solids next time, it's not as good as filtering but it's very close. The only alternative is to buy some cheap syringe filters of 0.2-0.4um from amazon or ebay because I'm not paying for the VST branded ones, I'd rather avoid the waste if not also the cost.


 If you have/get a centrifuge you'll probably be OK without syringe filters.

I haven't seen the VST filters (the only ones designed to filter coffee) under any other brand name.

The oils are solids, you're trying to separate the solution (unfilterable to all intents & purposes, from oil, solids & crema.

If things are going well there's probably not much need to sample more than one or two shots per bag, because that's what makes the biggest difference.


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## MWJB

MWJB said:


> If you have/get a centrifuge you'll probably be OK without syringe filters.
> 
> I haven't seen the VST filters (the only ones designed to filter coffee) under any other brand name.
> 
> The oils are solids, you're trying to separate the solution (unfilterable to all intents & purposes), from oil, solids & crema.
> 
> If things are going well there's probably not much need to sample more than one or two shots per bag, because that's what makes the biggest difference.


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