# Any Londoners willing to test their grinder on my MaraX?



## PD2020 (May 27, 2020)

Dear Londoners,

I'm currently getting sour coffee on my MaraX + Niche Zero combo. I suspect a problem with one of the two and I'd like to test them one by one. Also, more than anything, it would be great to get another pair of (experienced) eyes on my workflow and the taste the coffee to confirm my diagnosis.

(1) If you have a spare grinder, ideally a Niche, that I could borrow for a day to test it on my MaraX, that would be great. Or you're welcome to visit me and we could dial in some coffee together on your grinder against my MaraX

(2) Would anybody in London be willing to have me bring my Niche and test whether it makes tasty coffee on their machine?

I'm located at Bromley by Bow (between Canary Wharf and Stratford). I'm 3m away from the tube station and the 5m away from Devon's Road DLR station.

I appreciate it's a long shot during corona but it would be really helpful.

Cheers.

More details at:

https://www.coffeeforums.co.uk/topic/54792-dialling-in-origin-gesha-as-espresso?do=embed


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## Blue_Cafe (Jun 22, 2020)

Will you be providing the hazmat suits?


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## MWJB (Feb 28, 2012)

Grinders don't make tasty coffee, you buy tasty coffee & the grinder breaks the beans into little pieces for you to then make tasty coffee. The grinder would normally need to be quite obviously broken to not be able to carry out its job to a normal degree.


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## PD2020 (May 27, 2020)

Fair point, MWJB. I think that my Niche is working great. This is basically just binary testing of the components in isolation.

Anyway as the machine is a more likely candidate to cause issues, I have renamed the thread to "Any Londoners willing to test their grinder on my MaraX?"


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## Rob1 (Apr 9, 2015)

I'd be looking at water quality rather than grinder. What have you used to remineralise? I've had very few sour shots from the Niche, all of them very obviously wrong grind settings when switching to a new coffee. If you're getting sour shots grind a bit finer, don't worry about time increasing to 40 seconds+.

Why would the MaraX be the issue? Do you think the temperature is off somehow?


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## PD2020 (May 27, 2020)

Hi Rob1. Thanks for replying.

I have been using Soda Bicarb and Epsom Salts. First I tested the Osmio Water for KH and GH with the extended API test (20ml) before. Then added enough Soda Bicarb and Espom Salts to get the water to the SCA spec (40KH + 68GH). Finally I retested with API test to confirm the output. Also used TDS meter to confirm the total dissolved solids to be at around 110.

The remineralised water tastes clearly better and nicely balanced compared to the RO water straight from Osmio, which has a slightly acidic (I guess) test. Tasting was done by both me and one more person several times.

I will retry the super fine grind setting today. Thanks for the tip. Last time I tried it the coffee cone was forming WAY slower than in DaveC's videos, and I was getting visible channels on the spent puck. I'll retest today on the same beans.


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## Rob1 (Apr 9, 2015)

I didn't get on well with epsom salts. If you can brew with your water for any other method you'll eliminate water as a possibility though, cupping might be enough.

In the previous thread you mention you enjoyed the shot when you added 100ml water to it which suggests your palate isn't adjusted to the strength of espresso, or you otherwise simply don't like it. If you've made espresso you like before with some beans then it stands to reason you just don't like the beans you're currently using....

Don't focus on what somebody else is doing with a different coffee. They'll have a different grind setting and maybe a different dose, aside from the fact they're using different coffee.


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## spasypaddy (Apr 11, 2016)

london is a big place, where in london are you?


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## MediumRoastSteam (Jul 7, 2015)

PD2020 said:


> Hi Rob1. Thanks for replying.
> 
> I have been using Soda Bicarb and Epsom Salts. First I tested the Osmio Water for KH and GH with the extended API test (20ml) before. Then added enough Soda Bicarb and Espom Salts to get the water to the SCA spec (40KH + 68GH). Finally I retested with API test to confirm the output. Also used TDS meter to confirm the total dissolved solids to be at around 110.
> 
> ...


 The beauty of the MaraX... It's an HX machine. Bring the machine up to temp. Empty the tank, dump a bottle (2L) of Waitrose Essentials Lockhills into the tank. Flush 200ml. Brew some coffee. See it tastes better. This way you are eliminating the water variable.


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## PD2020 (May 27, 2020)

Bromley by Bow (between Canary Wharf and Stratford). I'm 3m away from the tube station and the 5m away from Devon's Road DLR station.


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## PD2020 (May 27, 2020)

Hi MediumSteamRoast. Yeah, good idea. I'm going to try that today too. I'll go get some Volvic later on - should be good, right?


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## PD2020 (May 27, 2020)

Rob1 said:


> In the previous thread you mention you enjoyed the shot when you added 100ml water to it which suggests your palate isn't adjusted to the strength of espresso, or you otherwise simply don't like it. If you've made espresso you like before with some beans then it stands to reason you just don't like the beans you're currently using....


 Yeah, diluting it made it nice, but mind you, when I say nice it was coming from a person that has just had a harsh sour espresso. Of course it was much nicer when diluted 

I gave a sample of that Americano to my girlfriend and she didn't enjoy it at all calling it "the opposite of bitter" - meaning sour 😉

I'm going to get some bottled water (Volvic), put that into my machine, and see if it makes a difference.


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## MediumRoastSteam (Jul 7, 2015)

PD2020 said:


> Hi MediumSteamRoast. Yeah, good idea. I'm going to try that today too. I'll go get some Volvic later on - should be good, right?


 Yep! (ps: I got a new forum name it seems.. 😂👍)


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## PD2020 (May 27, 2020)

By the way, in the previous I posted a photo of the Bicarb of Soda and Epsom Salt I'm using. Could you please confirm these are the products typically used by people who remineralise their water? Just want to make sure I'm not putting the obviously wrong product in.


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## PD2020 (May 27, 2020)

MediumRoastSteam said:


> Yep! (ps: I got a new forum name it seems.. 😂👍)


 Haha, sorry for that 😉 I'm doing multiple things at the same time and I'm not a multitasking kind of person really 😉


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## Rob1 (Apr 9, 2015)

PD2020 said:


> By the way, in the previous I posted a photo of the Bicarb of Soda and Epsom Salt I'm using. Could you please confirm these are the products typically used by people who remineralise their water? Just want to make sure I'm not putting the obviously wrong product in.


 I'm not sure about either of those specifically. If they are only what they say they are then fine. Just make sure there are no additives listed on the label like anti-caking agents.


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## PD2020 (May 27, 2020)

I can't see any additives.


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## spasypaddy (Apr 11, 2016)

PD2020 said:


> Bromley by Bow (between Canary Wharf and Stratford). I'm 3m away from the tube station and the 5m away from Devon's Road DLR station.


 im in hackney with a specialita but my gf is too corona scared for this to happen. hopefully someone else can help you out.

What beans are you using btw?


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## PD2020 (May 27, 2020)

Right now: Origin Gesha (https://www.origincoffee.co.uk/products/san-jose-gesha), and Square Mile Espresso Decaf (https://shop.squaremilecoffee.com/products/decaf-espresso).

I've tried other beans before though.

The only beans which gave me a truly non-sour espresso were HasBean Decaf (https://www.hasbean.co.uk/products/colombia-finca-la-chorrera-decaf?variant=14997579333667.)


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## AJP80 (Feb 29, 2020)

PD2020 said:


> I can't see any additives.
> 
> View attachment 45502


 The bicarbonate, I don't recognise, and the ingredient list looks odd, but that could just be cake speak for 100% sodium bicarbonate (which is what my packet says).

The Epsom Salts are the exact ones I use, though note (as you probably are aware) that it isn't pure magnesium sulphate; there is water in the crystals which you will need to account for when dosing (this may already be done for you if you are following e.g. a Barista Hustle DIY recipe, which also uses Epsom Salts rather than pure magnesium sulphate).

I like the taste of Epsom Salts in my water for brewed coffee (e.g. V60). I have never used it for espresso, though, so can't comment on its taste in that context.


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## PD2020 (May 27, 2020)

AJP80 said:


> The bicarbonate, I don't recognise, and the ingredient list looks odd, but that could just be cake speak for 100% sodium bicarbonate (which is what my packet says).
> 
> The Epsom Salts are the exact ones I use, though note (as you are probably aware) that it isn't pure magnesium sulphate; there is water in the crystals which you will need to account for when dosing (this may already be done for you if you are following e.g. a Barista Hustle DIY recipe, which also uses Epsom Salts rather than pure magnesium sulphate.
> 
> I like the taste of Epsom Salts in my water for brewed coffee (e.g. V60). I have never used it for espresso, though, so can't comment on its taste in that context.


 Hi AJP80, thank you for helping out.

I am using the Barista Hustle way of "making water"  I dilute 2.45g of Epsom Salt in 1L of Osmio water, and 1.68g of Sodium Bicarb in 1L of Osmio. The only difference is Osmio isn't exactly pure, it does have TDS ranging from mostly 25 to 50. That's why I've done lots of API kit testing (extended to 20ml probe) to make sure I'm adding things correctly. I have never put water with more than 120TDS into my machine. It's always aim for 110 TDS +- 3 and err on the side of 'less' than 'more'.

Also I've just put Volvic into my tank. So I'll make some coffee in the lunch break and we'll find out whether water was the culprit.


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## Inspector (Feb 23, 2017)

I read Dave recommended adding 0.08gr of baking soda to a 1L of Osmio water.


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## PD2020 (May 27, 2020)

Hi Inspector. Yes, you could do that as well. The tricky is that Osmio water has variable KH/GH depending on when you drew some water last, how long it's been sitting in the tank, and at how concentrated the water in the tank is.

To keep things simple I'm going to run a test using Volvic very soon just to be sure whether it's a water-related problem. I'll report back.


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## Doram (Oct 12, 2012)

PD2020 said:


> I will retry the super fine grind setting today. Thanks for the tip. Last time I tried it the coffee cone was forming WAY slower than in DaveC's videos, and I was getting visible channels on the spent puck


 If you are already getting channeling with the current grind, isn't that more likely to be the cause of under extraction and sourness than the water? And if you go even finer, wouldn't that make the channeling and sourness problem worse? Maybe the first thing is to try and get rid of the channeling by better distribution and grinding coarser? I consider myself a newbie like yourself, often struggling with the same confusions, so perhaps someone with more experience can comment if what I am saying makes any sense?


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## Doram (Oct 12, 2012)

.


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## PD2020 (May 27, 2020)

I've done tests with Volvic. Here's the procedure.

A. Take the water tank out, get the water out and put only Volvic in, then flush 200ml via grouphead (lever)

B. Medium temperature setting (93-94*C), portafilter and basket warmed up, machine ready.

C. 3 shots on VST 15g, stirring with LDT, even bed before tamp, flat tamp, after each shot brush leftover coffee off to keep it warm:

1) 15g in, 38.8g out, grinder setting 6, 24s flowing time, 35s total time - super sour

2) 15g in, 38.5 out, grinder setting 5, 26s flowing time, 38s total time - super sour

3) 15g in, 38.8g out, grinder setting 4.5, ? flowing time (missed it), 37s total time - sour

D. Clean grouphead with Pallo, blackflush with water, put portafilter and clean basket back in, wait 15 min

E. Another 3 shots on VST 15g, same procedure as above:

4) 15g in, 39.1g out, grinder setting 4, 30s flowing time, 42s total time - super sour

5) 15g in, 38.8g out, grinder setting 3, 31s flowing time, 43s total time - super sour

6) 15g in, 39.1g out, grinder setting 2, 36s flowing time, 51s total time - super sour, outside in channeling

The first 3 shots looked ok visually on the bottomless portafiltes .The times were as expected too. But sour.

All the shot cones (streams) looked watery in their second halves of extraction. The finer I ground, I think the more watery they appeared, and definitely the longer the cone formation took (it was very long in particular in the last shots)

I diluted the first 3 shots with the most "expected" total times with water and tried them as Americano with my girfriend. Obviously more pleasant because diluted, but still sour. My girlfriend said "yeah, I wouldn't drink it" 😉

I'm attaching the pics from my mobile phone in the next post.


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## PD2020 (May 27, 2020)

Coffee from shot number 1 and 2


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## PD2020 (May 27, 2020)

Niche grind output


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## PD2020 (May 27, 2020)

Grinds after transferring to the portafilter


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## PD2020 (May 27, 2020)

Grinds after distribution with LDT, before tamping


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## PD2020 (May 27, 2020)

After tamping


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## PD2020 (May 27, 2020)

Spent puck after the 51s shot on niche setting 2 (notice a little impression on the lefthand side at 9 o'clock - I notice it quite often, but not always at 9; it appears at "random" positions)


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## PD2020 (May 27, 2020)

Doram said:


> If you are already getting channeling with the current grind, isn't that more likely to be the cause of under extraction and sourness than the water? And if you go even finer, wouldn't that make the channeling and sourness problem worse? Maybe the first thing is to try and get rid of the channeling by better distribution and grinding coarser? I consider myself a newbie like yourself, often struggling with the same confusions, so perhaps someone with more experience can comment if what I am saying makes any sense?


 Indeed that's what I've been doing for all the months since I bought my espresso machinery - going coarser (the reason was different though - I thought that sensation was 'bitter' so I fixing it by going coarser). That gave me shorter total shot times around 23-32s which seems too short for MaraX. Indeed that made shots more palatable but never clean.

It was with help of @MediumRoastSteam that I rethought my 'bitter' assessment and he was right - I was wrongly classifying the shot as bitter. I happened to have lovely Cherry Decaf beans from HasBean and by grinding them finer I got to the point of getting a really clear shot and it was mindblowing. I tried even finer - and then got the real 'bitter' - the bitter I know from very dark chocolate or grapefruit peel. So yeah, I learned I was always drinking sour shots (apart from HasBean Decaf).

One reason why I've been drinking sour coffee for so long without realising it was that I used to make only lattes and flat whites. It was only recently, after a visit to Cambridge and trying the espresso from Hot Numbers Coffee, that I realised how great pure espresso can be and I loved that apple acidity a lot so I bought more-acidic-than-chocolatey beans to replicate it at home. And this time without hot milk (or hot water - reducing the perception of sourness) 😉

Another strong hint that going coarser is possibly wrong is that the shot cone becomes really thick, as you'd expect from a fast shot.

What I might be getting however is some microchannelling that's invisible on bottomless portafilter (I think my shots look very nice). But I didn't get it with HasBean Decaf - it was a similarly looking cone, stream, timing, and yet the flavours were much clearer, there was no sour harshness clouding whatever's in the cup, and even when I had my grinder setting off by 0.5 or 1, the shot was still fine. Whereas with any other beans - I'm getting harsh sour.


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## AJP80 (Feb 29, 2020)

My gut says machine (temperature) or beans (perhaps I missed it but not sure if you get sour with familiar espresso roasts). Are you able to measure or guesstimate water temp out of the group head?


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## PD2020 (May 27, 2020)

That's a good question. I have just done an experiment.

I preheated a cappuccino glass with boiling water from my electric kettle - the thermometer was showing 93*C in the glass.

I left the hot water in for a minute, poured it into the sink, then immediately drew some water from my MaraX into the preheated glass holding a thermometer in it - 86*C.

MaraX is set to Temperature Setting 1 (93-94*C).

I wish I had an E61 thermometer to do a proper test but they cost £70 from what I've seen...


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## Inspector (Feb 23, 2017)

https://www.shadesofcoffee.co.uk/e61-digital-group-thermometer

£35 delivered.

use code *CFUK-E61THERM*


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## PD2020 (May 27, 2020)

Thanks Inspector. I've just ordered one.


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## MWJB (Feb 28, 2012)

PD2020 said:


> The first 3 shots looked ok visually on the bottomless portafiltes .The times were as expected too. But sour.
> 
> All the shot cones (streams) looked watery in their second halves of extraction. The finer I ground, I think the more watery they appeared, and definitely the longer the cone formation took (it was very long in particular in the last shots)
> 
> ...


 How the shots looked, if too sour, isn't useful.

All shots go watery as extraction progress, obsessing on cones & how things look is going to drag out your woes.

Do you generally drink the espresso neat, you have mentioned diluting a couple of times? What is the weight of your finished, diluted beverage.

Dilution can't fix extraction, because extraction is done & dusted before you add dilution water.

If shots remained sour from setting 6 downwards, it's time to explore coarser settings. Maybe make 1 or 2 shots, then report back.

All the shots you made were 15:<40g. If ratio is limiting your extraction try a longer ratio.


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## PD2020 (May 27, 2020)

I will try to record a video of a shot later on and revisit some coarser settings as well.

I tried longer ratios before but not on coarser (around 2.3ml/s) settings.


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## Doram (Oct 12, 2012)

PD2020 said:


> preheated a cappuccino glass with boiling water from my electric kettle - the thermometer was showing 93*C in the glass.
> 
> I left the hot water in for a minute, poured it into the sink, then immediately drew some water from my MaraX into the preheated glass holding a thermometer in it - 86*C.
> 
> MaraX is set to Temperature Setting 1 (93-94*C).


 Doesn't your experiment show that the temperature seems fine? You got a 7C difference between boiling water and brew water. Assuming your boiling water was 100C, then it makes sense that your brew water was ~93C, which is what it was supposed to be. Or am I missing something?


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## PD2020 (May 27, 2020)

Doram said:


> Doesn't your experiment show that the temperature seems fine? You got a 7C difference between boiling water and brew water. Assuming your boiling water was 100C, then it makes sense that your brew water was ~93C, which is what it was supposed to be. Or am I missing something?


 Yeah, that's fair. Not sure if we can assume the difference of 7*C but what I can tell you is that the water doesn't certainly feel cold. I had to be careful when holding my hands around the water stream because it certainly felt very hot.


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## MWJB (Feb 28, 2012)

PD2020 said:


> I will try to record a video of a shot later on and revisit some coarser settings as well.
> 
> I tried longer ratios before but not on coarser (around 2.3ml/s) settings.


 You can't taste flow rate. Flow rate is just a function of brew ratio, you can extract coffee to the same extraction over a very wide range of ratios, the flow rate will not be constant at different ratios.

You can taste flavour balance, which correlates to extraction (assuming no other faults, like overly silty cup, catastrophic channeling). Ratio & grind are the biggest drivers for extraction.


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## PD2020 (May 27, 2020)

That makes sense. Thanks.

Assuming I'm grinding too fine and getting sour out of it, do you think it makes sense to go back to the classic 1:2 ratio instead of 1:2.5? I wrote the Square Mile team and they confirmed they brew this Espresso Decaf bean with 1:2 ratio, 28-32 seconds, temperature of "around 92-95 degrees".

If that's the case, then perhaps I shouldn't be exploring at 1:2.5? I focused most of my effort on this ratio (not all of it by all means) because I was trying to push extraction and reduce the strength (the latter in order to minimise a risk of disliking a shot due to the strength I'm not used to).


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## BlackCatCoffee (Apr 11, 2017)

Sorry if I am repeating things here but have you had this coffee before and enjoyed it? Do you normally go for quite modern acidic lighter roasts?

Looking at the photo of the coffee I would say it has quite low development and acidity is likely to pop.


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## MWJB (Feb 28, 2012)

PD2020 said:


> I am using the Barista Hustle way of "making water"  I dilute 2.45g of Epsom Salt in 1L of Osmio water, and 1.68g of Sodium Bicarb in 1L of Osmio.


 I take it, this is to make a concentrate, that you then dilute down again?


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## AJP80 (Feb 29, 2020)

Doram said:


> Doesn't your experiment show that the temperature seems fine? You got a 7C difference between boiling water and brew water. Assuming your boiling water was 100C, then it makes sense that your brew water was ~93C, which is what it was supposed to be. Or am I missing something?


 I would want to know what part of that 7 degree drop went on heating the glass so I would take another reading (using the preheated glass) with boiling water out of the kettle and use that as my point of reference. That said, even an omni roast shouldn't taste undrinkably sour at 90 degrees (assuming half of the 7 degree drop went on heating the glass).


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## PD2020 (May 27, 2020)

MWJB said:


> I take it, this is to make a concentrate, that you then dilute down again?


 Yup  This was just for the concentrates. Anyway, the last 6 shots were on Volvic and the flavour remained the same - sour.


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## PD2020 (May 27, 2020)

BlackCatCoffee said:


> Sorry if I am repeating things here but have you had this coffee before and enjoyed it? Do you normally go for quite modern acidic lighter roasts?
> 
> Looking at the photo of the coffee I would say it has quite low development and acidity is likely to pop.


 Very good question, BlackCatCoffee.

I haven't tried Square Mile Espresso Decaf beans in any shops. That's why I mailed them asking for their recipe.

In terms of lighter coffee I had this one at Cambridge's Hot Numbers Coffee: https://hotnumberscoffee.co.uk/product/peru-pilar-samame-monslave/ . It had a strong apple acidity which I loved. I had never experienced anything this nommy in my admittedly short black-coffee-life.

A couple of weeks ago I bought beans from Notes having tasted it at the shop. Then I was trying to reproduce it at home (obviously accepting I've got a different grinder, machine, and everything) but I haven't got to the cleanliness of the shot at the shop. I made it less sour over time by grinding finer but my shots couldn't be described as clean.

I wouldn't be reporting this as an issue if it was one bag of beans but I've getting this harshness very consistently.

I've ordered also some darker coffee (Rave's Chatswood) which should arrive today, but I'll have to give it some rest time before trying it again.

I'd be disappointed if espresso is supposed to taste like this, because I've had it way better. I would love if somebody was kind enough to visit me and try the coffee on my setup to verify my experience.


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## Rapid (Jun 12, 2020)

BlackCatCoffee said:


> Sorry if I am repeating things here but have you had this coffee before and enjoyed it? Do you normally go for quite modern acidic lighter roasts?
> 
> Looking at the photo of the coffee I would say it has quite low development and acidity is likely to pop.


 Possibly mistaking high acidity for sourness? I guess that's possible. Some people struggle to differentiate sourness and bitterness.


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## PD2020 (May 27, 2020)

Rapid said:


> Possibly mistaking high acidity for sourness? I guess that's possible. Some people struggle to differentiate sourness and bitterness.


 Possibly.

I've done my best to discern the two by running a test of thirds (catching a coffee shot into multiple glasses and tasting them one by one), diluting my espresso into an Americano, and this one time when I dialed in a clean espresso shot, I was grinding finer to remove the 'sour' - and it worked (moreover, when I went even finer - the flavour was distinctively different and it was the 'bitter' you'd know from a super dark chocolate or grapefruit peel).


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## BlackCatCoffee (Apr 11, 2017)

Just thought I would put it out there. I remember a few years ago taking a friend to a superb coffee roaster in London telling him what a treat it would be as he is a big coffee drinker. It turns out we had very different ideas about what constitutes nice fruity flavours.


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## Rob1 (Apr 9, 2015)

I think at the end of the day if I were in your position I'd chalk it up to the beans, but I rarely have bad shots, have been at this for years, and have the confidence to say that I just don't like something rather than doubt my technique and equipment. There certainly doesn't appear to be anything wrong with your prep or your equipment so either you don't like the beans (despite enjoying a similar roast level of another coffee before) or the beans are poorly roasted. I think the latter can be ruled out quite safely.


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## PD2020 (May 27, 2020)

Fair points, agreed.

It's difficult to discuss taste over Internet 😉 I think I need to pick a coffee shop in London that makes good espresso, taste it, buy lots of their coffee and try to reproduce it at home. That's the only way I can verify my diagnosis of super sour coffee on my own, without help of an experienced coffee drinker.

Any suggestions for a good coffee shop making good lighter-medium roast espresso?


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## earthflattener (Jul 27, 2015)

I don't have anything like the experience of the others here, but had been struggling with acidity in the beans that I'm currently using. Finally I've ended up using 95C and running the shot at 6 bar rather than 9 bar (18 in 40 out in about 43s). That seems to have cleared it up.

One thing I don't quite understand though is the grind level difference between what you are using and me. Also on a Niche, but mine is at 18.2 (ish). I'm fairly sure if I were to grind at 5 or 6 i'm fairly sure it would choke. They are probably calibrated differently (I'm still using the default that I got with the machine)...but that seems a massive difference, no?


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## PD2020 (May 27, 2020)

earthflattener said:


> I don't have anything like the experience of the others here, but had been struggling with acidity in the beans that I'm currently using. Finally I've ended up using 95C and running the shot at 6 bar rather than 9 bar (18 in 40 out in about 43s). That seems to have cleared it up.
> 
> One thing I don't quite understand though is the grind level difference between what you are using and me. Also on a Niche, but mine is at 18.2 (ish). I'm fairly sure if I were to grind at 5 or 6 i'm fairly sure it would choke. They are probably calibrated differently (I'm still using the default that I got with the machine)...but that seems a massive difference, no?


 Yes, don't worry about the number. It's a matter of calibration. Different people get different numbers.

Pressure is something I haven't explored until now. I'm running on the MaraX factory settings. That said for the beans I bought (for example Square Mile Decaf Espresso, or previously Notes fazenda um espresso) - they don't recommend going down to 6 bar. When I chatted to them they are using the most basic espresso recipe: 94-95*C, 1:2 ratio, 9 bar. It seems to me there must be a way to make nice coffee out of 9 bar pressure and while 6 bar can be beneficial, it shouldn't be a requirement 

PS: what beans are you using?


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## AJP80 (Feb 29, 2020)

PD2020 said:


> A couple of weeks ago I bought beans from Notes having tasted it at the shop. Then I was trying to reproduce it at home (obviously accepting I've got a different grinder, machine, and everything) but I haven't got to the cleanliness of the shot at the shop. I made it less sour over time by grinding finer but my shots couldn't be described as clean.


 Notes does good, lighter medium roast espresso, although they use large, flat burr grinders (clima pros, I think). I always struggled to get clean acidity with a conical grinder, finding the shots muddy and harsh no matter what I did, however I think it was an issue with my specific grinder (it too had 68mm burrs) as a lot of the cafes around me made great espresso using Red Brick in Roburs.


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## earthflattener (Jul 27, 2015)

My working hypotheses was that if its acidic, I need to expose the more of the coffee to hot water for longer (that idea may be part horse poo?). Changing pressure allows that to happen, but presumably having a smaller pressure difference also makes the water flood front more stable in the puck which should reduce channeling.

The other route is finer grind of course, and I think I will continue experimenting to try and push that lower (back at 9 bar). First attempts at that were not too promising, but I'll persist. My harebrained hypothesis for this is it may well destabilize the water flood front somewhat compared to a low pressure slightly coarser run (=> channeling)


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## PD2020 (May 27, 2020)

earthflattener said:


> My working hypotheses was that if its acidic, I need to expose the more of the coffee to hot water for longer (that idea may be part horse poo?). Changing pressure allows that to happen, but presumably having a smaller pressure difference also makes the water flood front more stable in the puck which should reduce channeling.
> 
> The other route is finer grind of course, and I think I will continue experimenting to try and push that lower (back at 9 bar). First attempts at that were not too promising, but I'll persist. My harebrained hypothesis for this is it may well destabilize the water flood front somewhat compared to a low pressure slightly coarser run (=> channeling)


 That's what they talk about in the Barista Hustle courses. You want to the highest possible pressure that's not causing channeling. That tends to be around 9 bars. There are also other ways of making coffee where you run at much lower pressures for much longer, etc higher pressures, but that's rather advanced techniques. I think for us beginners staying at the default of 9 bars and learning to get good results with it is the way to go 

I have no idea what machine you have though. It all depends on the machinery, coffee, distribution...


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## earthflattener (Jul 27, 2015)

Actually...another hairbrained idea. I think it's called front dumping or some such (read it on a US site). Since a lot of the acidity seems to be associated with the early part of flow, don't start to collect the coffee for the first few seconds - while it is still running black without crema. Wait until the the crema appears in all its majesty.


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## earthflattener (Jul 27, 2015)

I have a sage double boiler - very easy to reduce pressure....all I do is run preinfusion at 6 bar for 90 seconds which is enough to finish the shot at the low pressure. You are no doubt right. I should play by the book until I've got it right.


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## PD2020 (May 27, 2020)

earthflattener said:


> Actually...another hairbrained idea. I think it's called front dumping or some such (read it on a US site). Since a lot of the acidity seems to be associated with the early part of flow, don't start to collect the coffee for the first few seconds - while it is still running black without crema. Wait until the the crema appears in all its majesty.


 That sounds a bit like departing from the standard espresso practices 😉 I've heard that tea afficinados do that (last Decent Zoom call talks about it too). Feel free to experiment of course.

I think I'd like to stick to the more standard espresso practices and get some drinkable stuff there 😉 Then perhaps explore more adventurous paths 😉


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## Northern_Monkey (Sep 11, 2018)

@PD2020 - The coffee looks a lot more ginger snap than Bourbon biscuit to be honest. I would chalk it up to experience and try some other beans, as it might not be developed enough to ever taste sweet to you.

I've had some very light filter roasts that even going super fine (0.75 dial versus 4-2 normally) on an EK with Turkish burrs and preinfusion for an age with a flow paddle couldn't give me a pleasant tasting espresso ...


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## PD2020 (May 27, 2020)

Northern_Monkey said:


> @PD2020 - The coffee looks a lot more ginger snap than Bourbon biscuit to be honest. I would chalk it up to experience and try some other beans, as it might not be developed enough to ever taste sweet to you.
> 
> I've had some very light filter roasts that even going super fine (0.75 dial versus 4-2 normally) on an EK with Turkish burrs and preinfusion for an age with a flow paddle couldn't give me a pleasant tasting espresso ...


 Hi Norhern_Monkey, thanks for replying.

I think my photos aren't of best quality and it's hard to assess the real colour of the grind. I would say the photo that shows the real colour is the one entitled "Grinds after distribution with LDT, before tamping". Trust me it's not ginger snap.

Looking at the recommended recipe at https://shop.squaremilecoffee.com/products/decaf-espresso (I confirmed the recipe via email with Square Mile), it doesn't look a super light bean to me. To my uneducated eyes the colour of the grind, the taste of a raw bean, the look of a raw bean - all that indicates medium.


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## Mrboots2u (May 10, 2013)

PD2020 said:


> That sounds a bit like departing from the standard espresso practices 😉 I've heard that tea afficinados do that (last Decent Zoom call talks about it too). Feel free to experiment of course.
> 
> I think I'd like to stick to the more standard espresso practices and get some drinkable stuff there 😉 Then perhaps explore more adventurous paths 😉


 Please dont do dumping , its gets you nowhere in making and understanding how to dial in consistent espresso


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## PD2020 (May 27, 2020)

I've done 2 coarser grind shots for @MWJB:

1) 15g in, 31g out, grinder setting 6.5, flowing time 18s, total shot time 25s (see the video below)

2) 15g in, 30.6g out, grinder setting 7, flowing time 15s, total shot time 23s

Both extremely sour and very fast flowing, as I had suspected.

Here's a video of the prepup and the shot 1. Sorry for the quality. I was going to upload a good resolution video but it's taking ages. Should still give you an idea of what I'm doing (be gentle, I'm a newbie ;-)).


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## MWJB (Feb 28, 2012)

PD2020 said:


> I've done 2 coarser grind shots for @MWJB:
> 
> 1) 15g in, 31g out, grinder setting 6.5, flowing time 18s, total shot time 25s (see the video below)
> 
> ...


 I didn't tell you to pull 1:2 shots, did I?

Your previous shots were 15:40 (1:2.7). Even if you made no change in grind, pulling at 1:2 would have extracted less. You are trying to extract more. This means more water pushed through the puck.

As your previous 6 shots were all sour at 1:2.7. and you could not beat the sourness with finer grinds, your only option is to go longer on ratio. This will likely also require a coarser grind than "6". There comes a point when you grind too fine that you drop extraction because the puck is not permeable enough to wet & extract evenly.


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## PD2020 (May 27, 2020)

Apology, @MWJB. I misunderstood you. I see what you're going for now. Happy to pull a longer shot at 6.5-7 on Niche. I'll report back in a moment.


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## earthflattener (Jul 27, 2015)

Mrboots2u said:


> Please dont do dumping , its gets you nowhere in making and understanding how to dial in consistent espresso


 Happy to accept your advice. Not a good way to start. I just thought it might give him something drinkable before his kg is gone.

As a reference, this is where I found it being advocated. I also have vague memories of being taught to stop by colour of the flow when I first tried making espresso in the mid 70s and some of the barmen started late too. That was in a fast moving bar situation, so weighing was not an option https://www.home-barista.com/espresso-guide-diagnose-extraction-problems.html


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## Northern_Monkey (Sep 11, 2018)

@PD2020 - Ah, I hadn't realised it was a decaf for some reason. Thanks for clearing up the roast level. I got mixed up with another thread on a lighter roast coffee. 😂

Only ever tried water processed decaf before which were super finicky, will be interesting to see how the CO2 processing affects your workflow.


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## AJP80 (Feb 29, 2020)

Not sure if it's related to your problem, but just an observation, you either have very strong fingers or your tamp is on the light side (or mine is super heavy).


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## PD2020 (May 27, 2020)

MWJB said:


> I didn't tell you to pull 1:2 shots, did I?
> 
> Your previous shots were 15:40 (1:2.7). Even if you made no change in grind, pulling at 1:2 would have extracted less. You are trying to extract more. This means more water pushed through the puck.
> 
> As your previous 6 shots were all sour at 1:2.7. and you could not beat the sourness with finer grinds, your only option is to go longer on ratio. This will likely also require a coarser grind than "6". There comes a point when you grind too fine that you drop extraction because the puck is not permeable enough to wet & extract evenly.


 Two extra shots:

15g in, 38g out, grinder setting 7, flowing time 19s, total shot time 26s - very sour

15g in, 45.5g out, grinder setting 7, flowing time 24s, total shot time 32s - very sour and thin bodied


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## Mrboots2u (May 10, 2013)

earthflattener said:


> Happy to accept your advice. Not a good way to start. I just thought it might give him something drinkable before his kg is gone.
> 
> As a reference, this is where I found it being advocated. I also have vague memories of being taught to stop by colour of the flow when I first tried making espresso in the mid 70s and some of the barmen started late too. That was in a fast moving bar situation, so weighing was not an option https://www.home-barista.com/espresso-guide-diagnose-extraction-problems.html


 Yeah thats fairy old school , there are still a lot fo advocates of using blonding around too, and if it works for them fair enough but its a language thats hard to share and help people with.


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## PD2020 (May 27, 2020)

AJP80 said:


> Not sure if it's related to your problem, but just an observation, you either have very strong fingers or your tamp is on the light side (or mine is super heavy).


 My tamp is light. I only go as far as the coffee compresses and no harder. Then I do the DaveC-style double check at different points of the basket and come back to the initial position.

I've tried different styles of tamping in the last months including harder tamping, but it seems that people suggest (1) tamping strength doesn't matter for extraction (2) light tamping until coffee compresses and no further is good for your wrist health 😉


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## PD2020 (May 27, 2020)

Northern_Monkey said:


> @PD2020 - Ah, I hadn't realised it was a decaf for some reason. Thanks for clearing up the roast level. I got mixed up with another thread on a lighter roast coffee. 😂
> 
> Only ever tried water processed decaf before which were super finicky, will be interesting to see how the CO2 processing affects your workflow.


 Yeah, decaf usually needs finer grind. Not sure how CO2 affects the workflow at this point of my coffee career 😉

I have come to the conclusion that given how much coffee I use for practising and trying to get rid of the 'sour' taste, I should stick to decaf and avoid overcaffeinating myself 

The other thread was about Gesha which I was hoping I'd be able to get a decent drink from after my first spectacular success dialing in espresso (thanks to @MediumRoastSteam) - using HasBean cherry decaf beans. I was wrong 😉

Today I've received 1kg of Rave's decaf, which is a more classic coffee profile. Once it's rested I'll give it a shot or two.


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## MWJB (Feb 28, 2012)

PD2020 said:


> Two extra shots:
> 
> 15g in, 38g out, grinder setting 7, flowing time 19s, total shot time 26s - very sour
> 
> 15g in, 45.5g out, grinder setting 7, flowing time 24s, total shot time 32s - very sour and thin bodied


 They can't be as thin as the ones you diluted with water? 1:3 is pretty normal, try 1:4. I make 1:5/6 shots frequently, these are obviously weaker than shorter shots, but rarely sour.

Flowing time isn't a thing, don't bother posting that. Post the time that you run the pump for.

In the video, I didn't see how you determined that you were achieving 15g in the basket? Why not try one of the larger doses/baskets, at the same strength & extraction you will get more mouthfeel with a larger dose. Weight the dose in the PF/basket to ensure it is what you think it is.


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## PD2020 (May 27, 2020)

MWJB said:


> They can't be as thin as the ones you diluted with water? 1:3 is pretty normal, try 1:4. I make 1:5/6 shots frequently, these are obviously weaker than shorter shots, but rarely sour.
> 
> Flowing time isn't a thing, don't bother posting that. Post the time that you run the pump for.
> 
> In the video, I didn't see how you determined that you were achieving 15g in the basket? Why not try one of the larger doses/baskets, at the same strength & extraction you will get more mouthfeel with a larger dose. Weight the dose in the PF/basket to ensure it is what you think it is.


 1:4 shot is coming this way. Give me 20 min (I've just locked the portafilter in to warm it up)

15g were scooped out and measured before the video. I put 15g into Niche expecting 14.9-15g to come out. I used to weight the grinds initially but at some point couldn't be bothered 😉 Niche seems to be very reliable.

Edit: Of course they're not as diluted as my Americanos. Just thinner than all my previous attempts. In my subjective terms I don't usually perceive ratio 1:2.5 as thin-bodied, my 1:3 with these beans felt like that to me.


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## MWJB (Feb 28, 2012)

PD2020 said:


> 1:4 shot is coming this way. Give me 20 min (I've just locked the portafilter in to warm it up)
> 
> 15g were scooped out and measured before the video. I put 15g into Niche expecting 14.9-15g to come out. I used to weight the grinds initially but at some point couldn't be bothered 😉 Niche seems to be very reliable.


 It can still be +/-0.4g as can any zero retention grinder, it's just that your scales aren't sensitive enough to detect this.


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## AJP80 (Feb 29, 2020)

PD2020 said:


> My tamp is light. I only go as far as the coffee compresses and no harder. Then I do the DaveC-style double check at different points of the basket and come back to the initial position.
> 
> I've tried different styles of tamping in the last months including harder tamping, but it seems that people suggest (1) tamping strength doesn't matter for extraction (2) light tamping until coffee compresses and no further is good for your wrist health 😉


 This is machine specific so might not apply to the Mara - if I tamped as light as you with my La Pavoni, the stream of water out of the boiler into the group head would blow a hole in my puck leading to a much _faster_ shot. That said, when this has happened, the espresso is long but not sour, so probably one to dismiss for you.


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## PD2020 (May 27, 2020)

MWJB said:


> It can still be +/-0.4g as can any zero retention grinder, it's just that your scales aren't sensitive enough to detect this.


 I'll make sure it's 15g in the basket for the next shot using Acaia Lunar after grinding.


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## PD2020 (May 27, 2020)

Two more shots with harder tamping (not extreme though) as per@AJP80; basket content measured on Acaia, @MWJB:

15g in, 38.5g out, grinder setting 7, 20s flowing time, I messed up recording total time - sour shot

15g in, 59.7g out, grinder setting 7, 35s total time - still sour

Again, when I say 'sour' I don't mean there's some acidity. I mean it makes my mouth pucker.


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## MWJB (Feb 28, 2012)

PD2020 said:


> Two more shots with harder tamping (not extreme though) as per@AJP80; basket content measured on Acaia, @MWJB:
> 
> 15g in, 38.5g out, grinder setting 7, 20s flowing time, I messed up recording total time - sour shot
> 
> ...


 Why are you reluctant to go larger than 15g dose?

Have you pulled any shots coarser than 7?

OK, go 15g in to 15-20g out.


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## PD2020 (May 27, 2020)

MWJB said:


> Why are you reluctant to go larger than 15g dose?
> 
> Have you pulled any shots coarser than 7?
> 
> OK, go 15g in to 15-20g out.


 I've tried higher doses during the weekend. Still same sour.

My shots were (mind you, I didn't record total time because MaraX doesn't have a timer):

19g in, 38.4g out, grinder setting 8, 23s flowing time,

19g in, 38.5g out, grinder setting 7, 28s flowing time (channeling - 2 holes in the puck)

19g in, 37.8g out, grinder setting 7.5, 26s flowing time

19g in, 39.4g out, grinder setting 9, 21s flowing time

19g in, 38.6g out, grinder setting 10, 20s flowing time

19g in, 38.4g out, grinder setting 11, 14s flowing time

18g in, 36.1g out, grinder setting 7, time not recorded

18g in, 38.6g out, grinder setting 8, 19s flowing time

18g in, 36.2g out, grinder setting 9, 18s flowing time

I didn't get an improved flavour out of that. So i sticked to 15g dose because bottomless is not showing any issues and it gives me more attempts. Also, given that I'm fighting 'sour' it allows me to grind finer.

I have perhaps 120g coffee left, so I'm happy to switch the dose but that will limit the number of experiments left.

Happy to do 15g in, 15-20g out.


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## MWJB (Feb 28, 2012)

PD2020 said:


> I've tried higher doses during the weekend. Still same sour.
> 
> My shots were (mind you, I didn't record total time because MaraX doesn't have a timer):
> 
> ...


 All those shots are about 1:2. There doesn't seem to be a clear method here.

You have issues with 15g, whether you can see them or not, because you can taste them.

Why is being able to grind finer a good thing, if it's not fixing your sourness? Espresso grind has a reasonable range of around 200 to 450um average, lots can work within that, finer is only better when it is better.


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## PD2020 (May 27, 2020)

Should we go for 1:3 with a dosis of 18g then? Or would you rather have me test 1:1? Let me know which dose and ratio we should try next please.


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## MWJB (Feb 28, 2012)

PD2020 said:


> Should we go for 1:3 with a dosis of 18g then? Or would you rather have me test 1:1? Let me know which dose and ratio we should try next please.


 What is most important to you? Do you want to pull normal, balanced shots, even if they are on the weaker side? Or, do you want mouthfeel? (Both these scenarios assume you do not want mouth puckering tartness).

15:15-20g at grind setting 7 should significantly under extract, with good mouthfeel, hopefully coming in under sourness. This could be the fastest route to getting a drink you can drink.

18:80g at setting 10 would give a good opportunity to extract, but it will be weak...then maybe you can trim back a little to bolster strength at a finer grind. Going forward, dealing with other coffees, this would be the better long term plan.


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## PD2020 (May 27, 2020)

Happy to try 18:80 then.


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## PD2020 (May 27, 2020)

I pulled 3 shots.

18g in, 80g out, grinder setting 10, total time 38s - not pleasant in flavour (it still seemed sour but maybe with a bit of bitter in it)

18g in, 45g out, grinder setting 7, total time 37s - super harsh but then when diluted as americano I sensed 'bitter' for the first time (!)

18g in, 45g out, grinder setting 8, total time 36s - again harsh but when diluted as americano there was a mix of sour and bitter (perhaps more sour than bitter)

So that's an interesting conclusion of the day.

I haven't been able to produce 'bitter' at the lower dose whatever I tried.

With your suggestions @MWJB of trying a higher dosis, I finally got some bitter. None of the shots were pleasant at all, I felt some harshness, dry throat, sourness, all at once perhaps. But that feels to me like progress.

Does that make any sense to you?

Unfortunately I've only got one shot of these beans left. Now I'll have to relax a wait for Rave beans to rest.

Also, good night everybody. You're all great. Thank you so much for helping out!


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## Rob1 (Apr 9, 2015)

MWJB said:


> I didn't tell you to pull 1:2 shots, did I?


 This tickled me.



> 3 hours ago, PD2020 said:
> 
> I've done 2 coarser grind shots for @MWJB:
> 
> ...


 I would have let that run to 45g at least. I can't say why it's just with a flow rate that fast and an 18g dose I'd be going 55+ out especially if it was a light roast and I had been finding it sour. You could try even more than that.

Making such small adjustments on the Niche is pointless when you're so far away from something drinkable, 1 notch and half a notch is tweaking to perfection territory, not god-no-that's-awful-get-me-out-of-here adjustment.


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## MWJB (Feb 28, 2012)

PD2020 said:


> I pulled 3 shots.
> 
> 18g in, 80g out, grinder setting 10, total time 38s - not pleasant in flavour (it still seemed sour but maybe with a bit of bitter in it)
> 
> ...


 Bitter is another failure mode (in fact it could be more than one). Bitter does not solely mean over-extraction, achieving bitterness is not progress, if we don't know the cause. You're making big & multiple changes & making lots of shots at each attempt. Slow down.

Are any of these shots reflective of he flavour notes outside the concepts of sour & bitter.

I'm not sure why your shots are taking so long.

18:80g sounds like it is still under, but grind is too fine. 18:45s sound like stronger more intense versions of the same. 80g to 45g out is a big jump & difficult to draw conclusions from because changes are not incremental & trackable.

Why are you diluting as Americano? What is the weight of the Americano?


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## spasypaddy (Apr 11, 2016)

im going to throw it out there that its the beans, im not that experienced in comparison to most people on here but i would park these beans for a while and get a darker more common espresso roast with the usual notes of chocolate, caramel etc etc

get your marax and niche dialled in with that, get a good shot out and then start working from there down to using a lighter roast. get your taste buds and equipment working at home on an 'easy' bean and then get experimenting with different lighter roasts.


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## PD2020 (May 27, 2020)

Yeah, I've now got Rave beans with more classic profiles resting. More than happy to try them again.


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## PD2020 (May 27, 2020)

MWJB said:


> Bitter is another failure mode (in fact it could be more than one). Bitter does not solely mean over-extraction, achieving bitterness is not progress, if we don't know the cause. You're making big & multiple changes & making lots of shots at each attempt. Slow down.
> 
> Are any of these shots reflective of he flavour notes outside the concepts of sour & bitter.
> 
> ...


 Hi @MWJB. Thanks once again for taking your time to help.

I'm not sure my vocabulary is rich enough to give you more than descriptors than: harsh, it leaves dry aftertaste in the back of the throat, undrinkable, absolutely none of the flavour notes from the roaster (peach/caramel/custard). What kind of descriptors would you be expecting?

The reason I diluted the shots as americanos was to give myself two chances to try the shot: one as espresso, one as an americano. I found it was a safer way for me to place a label "bitter" or "sour" on the shot, because in americanos the strength wouldn't be distracting. The way I made them was to add hot water to reach about 130ml total.

You also asked about my shots taking so long. From what I understand MaraX has a slower than usual pressure ramp up, if that helps. Other than that, not sure.

One last thing, people in this thread often refer to these Square Mile espresso decaf beans as "light roasts". I'm not convinced they are light. Roaster's description is here: https://shop.squaremilecoffee.com/products/decaf-espresso (peach/caramel/custard). Colour is not ginger brown but it's rather darker brown. I'd personally assess them to be medium. Probably my fault for having a parallel thread for Gesha beans, which, yes, are a lighter roast. I stopped using Gesha and moved onto Square Mile Decaf when I realised I was getting sourness from both, and I thought I'd keep Gesha just for V60.


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## spasypaddy (Apr 11, 2016)

someone may have said this already so sorry if im repeating someone else...

on the timer thing, start the timer the moment you press start on the machine and press stop when you reach desired weight.


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## MWJB (Feb 28, 2012)

PD2020 said:


> Hi @MWJB. Thanks once again for taking your time to help.
> 
> I'm not sure my vocabulary is rich enough to give you more than descriptors than: harsh, it leaves dry aftertaste in the back of the throat, undrinkable, absolutely none of the flavour notes from the roaster (peach/caramel/custard). What kind of descriptors would you be expecting?
> 
> The reason I diluted the shots as americanos was to give myself two chances to try the shot: one as espresso, one as an americano. I found it was a safer way for me to place a label "bitter" or "sour" on the shot, because in americanos the strength wouldn't be distracting. The way I made them was to add hot water to reach about 130ml total.


 If the shots were almost there, I'd suspect that you might pick up some hints of yellow fruit/caramel/toffee. The fact that nothing in the notes is identifiable suggest you're not quite in the ball-park yet.

If the strength of the shorter ratio shots is distracting & making it difficult for you to identify faults, then stop making them for now. Make shots you can evaluate & when you are happy with flavour balance, then work back to shorter ratios & finer grind.


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## PD2020 (May 27, 2020)

My most enjoyable strength across many beans so far has been 1:2.3.

I'm glad you mentioned 'silt' in the other thread (I'm trying to keep the James Hoffmann thread separate from my issues). I was going to say that my grind has felt to me a little silty. That might be a part of my problem and a higher dose like the standard 18g would help to minimise this risk.


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## bargi (May 7, 2020)

Sorry if it's been covered but I skimmed through.

Try 1:1 ie:ristretto, I've found this seems to be the way for me to go. Everything was just tasting sour.

Also found with lighter roast beans really neededing to temp surf for a good 10sec or so with a Gaggia (yes I know not the same but maybe if you can do something similar)


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## PD2020 (May 27, 2020)

Hi Coffeepeople. I have rested my Rave beans for 11 days now (https://ravecoffee.co.uk/collections/espresso-coffee-beans/products/seasonal-decaf-blend ; notes of a more classic profile: Cocoa, Vanilla, Red Fruits).

Yesterday I tried a number of shots with ratios going from 1.88 to 3.1, times varying from 25s to 55s, with dose of 18.2g in 18g VST basket, grinder setting anything between 8-12. Just can't shake off that combination of harsh, sour, and dry aftertaste... I didn't get any of the tasting notes.

The most plausible explanation until now is from @MWJB. The way I understand it is that the grind is too fine which reduces extraction (hence sour) and either overextracts some fines or pushes silt into the cup (hence dry aftertaste). But then I tried much coarser settings...

It's funny how it's exactly the same kind of harshness for pretty much any beans I have tried. It feels like there's some fundamental issue either in my technique or in the machinery I'm using. The only beans so far which were good were HasBean Decaf (https://www.hasbean.co.uk/products/colombia-finca-la-chorrera-decaf?variant=14997579333667) where I had a non-sour, non-bitter, balanced espresso at pretty much any shot around (18g->36-41g). Maybe not luscious and syrupy - but super clean (zero harshness; pleasantly drinkable on its own)

No idea what to else try at this point.


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## MWJB (Feb 28, 2012)

PD2020 said:


> Yesterday I tried a number of shots with ratios going from 1.88 to 3.1, times varying from 25s to 55s, with dose of 18.2g in 18g VST basket, grinder setting anything between 8-12. Just can't shake off that combination of harsh, sour, and dry aftertaste... I didn't get any of the tasting notes.


 This is where it becomes impossible to advise, or troubleshoot. Saying you tried a wide range of ratios & times doesn't allow us to see any trends, nor incremental changes.

If you were making incremental adjustments, it seems odd that you'd have a 55s shot in there. We really need to see grind setting & taste assessment for each shot.


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## PD2020 (May 27, 2020)

Absolutely. More than happy to do it properly this time.

What would be a good starting point for dose and yield? Rave's recommendation on their website is 20.5g->40g in 25-27s, so fairly standard. If possible, I prefer slightly lower dose (18g) so that I can get more shots out of the beans left.


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## Doram (Oct 12, 2012)

PD2020 said:


> Hi Coffeepeople. I have rested my Rave beans for 11 days now (https://ravecoffee.co.uk/collections/espresso-coffee-beans/products/seasonal-decaf-blend ; notes of a more classic profile: Cocoa, Vanilla, Red Fruits).


 I have to join someone else who said their hunch is that it is the beans. It seems to me that you tend to choose 'funky' special coffees. I had similar issues to yours with the same setup and 'special' beans. I then got a bag of no-frills 'classic' espresso blend, and it's been much easier to get good results with it. I see you did loads of tests and experiments and have not been getting the results you want. Perhaps it will be easier if you start by nailing some 'easy' beans, then move to more 'advanced' coffees when you know the kit better?


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## Doram (Oct 12, 2012)

.


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## PD2020 (May 27, 2020)

Doram said:


> I have to join someone else who said their hunch is that it is the beans. It seems to me that you tend to choose 'funky' special coffees. I has similar issues to yours with the same setup and 'special' beans. I got a bag of no-frills 'classic' espresso blend, and it's been much easier to get good results with it. I see you did loads of tests and experiments and have not been getting the results you want. Perhaps it will be easier if you start by nailing some 'easy' beans, then move to more 'advanced' coffees when you know the kit better?


 Heh, yeah. This is why I went to Rave and picked something that had "cocoa", "vanilla" and "medium/dark" in the description. I thought that was classic 😉 Could you please share an example of some nice beans that would be easier for learning?


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## Doram (Oct 12, 2012)

PD2020 said:


> Could you please share an example of some nice beans that would be easier for learning?


 I popped to a local roaster (in my case it's https://www.shopcoffee.co.uk/) and tried two espresso blends:
https://www.shopcoffee.co.uk/product/buy-coffee-beans-online/coffee-for-business/artisan-blend-1kg-coffee-beans-coffee-world/

and
https://www.shopcoffee.co.uk/product/buy-coffee-beans-online/coffee-for-business/mocha-italia-blend-1kg-coffee-beans-coffee-world/

I don't have a lot of experience, so maybe others can give you better ideas.

Or better still - simply drop an email to a local/reliable roaster with good reputation, tell them what you want (an easy, classic, fool-proof espresso blend to calibrate a new set up), and start from there?


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## PD2020 (May 27, 2020)

Inspector said:


> https://www.shadesofcoffee.co.uk/e61-digital-group-thermometer


 Hi @Inspector. I have installed the thermometer and yes, the temperatures look good. I think we can safely assume I'm the problem, and not the machine 😉

For medium Setting "I", idle temperature in the grouphead is oscillating around 92.5-93.5*C. During the shot it goes up to 95.5*C and then slowly decreases towards 93.5*C. Just like in Lelit video - 




Mind you this is only for the grouphead temperature. As Mauro said in the comments: "Salve, 96gradi Sono Del gruppo, con lo strumento sca rileviamo circa 93 in erogazione..." (96*C in the grouphead, Scace shows around 93*C) - you can see that in the other videos too.

Happy to move on to fixing my barista skills then


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## PD2020 (May 27, 2020)

Hi,

Today's shots with a well-rested, popular, darker chocolatey roast.

Rave Chatswood 250g - roasted on 21 September, opened 5 October (today):

https://ravecoffee.co.uk/products/chatswood-blend?variant=3151005548570

18g in, n/a out, setting 18, temperature medium (93-94*C), massive gusher

18g in, 36.2g out, setting 12, temperature medium (93-94*C), time 27s, sour

18g in, 36.3g out, setting 10, temperature medium (93-94*C), time 44s, sour

18g in, 36.0g out, setting 11 , temperature medium (93-94*C), time 41s, sour (channeling!)

18g in, 36.2g out, setting 11.5, temperature medium (93-94*C), time 30s, sour

Over the weekend I burned through almost the whole 1kg bag of Rave Decaf, even going as "extreme" as [18g in -> 90g out] and all the shots were sour. The only way to drink these shots is currently in milk.

I know shot times are not a reliable indicator on their own, but I noticed that many people on MaraX enjoy their shots from the time ballpark of 35-40s (including DaveC). For me getting into that ballpark is hard because channeling, super-slow cone formation, long time till first drop.

Among many things tried, I thought I'd report me trying Perger-style side-tapping of the portafilter (gif from Barista Hustle):










With my grinds it's just impossible because they're nowhere near this jumpy. They're almost rigid-solid. They don't behave like, say, rice grains. My grinds stick to each other way more. So hitting the portafilter doesn't cause much movement. Think tapping dried mud, it won't move much but it might fracture. Somewhat similar for me, not as rigid as a rock, but significantly less jumpy than in the pic. The grind almost always detaches from the walls of the basket and frequently fractures. Because of that I decided to give up on side-tapping in my first weeks after buying the espresso machinery and moved on to stirring with a cocktail stick (later Londinium Distribution Tool). Or similarly I can't do Scott Rao's "circular shake" (

__
http://instagr.am/p/BxJEmXJH_n6/
), because the grinds will stick to each other way more. Not sure if this is related but I'm out of ideas.

Similarly when I knock the spent puck out into the box, it doesn't just come out whole, there's usually plenty stuff left on the bottom, like the bottom layer of the puck is glued to the basket. I noticed the puck gets knocked out whole only when I'm up around setting 18 on Niche. Again, no idea if related...

My gut feeling is that the puck is not very permeable so I'm extracting very little. Perhaps because the grinds are so "gluey" instead of "jumpy"?

If anybody has ideas what to try, please shoot. Even if you think it's unlikely to help.


----------



## Rob1 (Apr 9, 2015)

Are you sure the grind setting isn't drifting as you grind? This happened on some Niches and the cause was some grease on the top of the outer burr carrier and the underside of the adjustment ring.



PD2020 said:


> Hi,
> 
> Today's shots with a well-rested, popular, darker chocolatey roast.
> 
> ...


 You've pulled a lot of shots and I'm struggling to make sense of any of them.

In order of coarsness:

12 - 27s

11.5 - 30s

11 - 41s

10 - 44s

All sour.

The time differences indicate to me a problem with distribution or tamping. 11-10 should be more than 3 seconds difference if 11.5-11 is 11 seconds difference. The point where you're grinding so fine you're getting channeling shouldn't be so close to setting 12 (11 in your example) so I don't know what's going on here.

Just refresh my memory: are these shots still sour when diluted in water or not?

I'd say try grind 12 and pull to 45g BUT....with a dark roast I don't think this should be necessary.

Your observations of the grind when tapping are most likely a result of your technique. Believe it or not it takes practice to tap properly (the gif illustrates a way it shouldn't be done). If you tap the portafilter down on the counter to settle the grinds they'll compact and be difficult to move around and you'll see what you're describing. Your spent puck sticking to the bottom of the basket is not because of the dry grounds. Are you tamping multiple times or tamping really hard? I've only seen pucks breaking in half in a basket if the grind is far too fine and/or if I tamp really hard or multiple times (e.g trying to correct an initially off level tamp).


----------



## Rob1 (Apr 9, 2015)

Oh and another thing I've noticed is how quickly you go through coffee making minor adjustments. The 250g bag isn't even going to last three days which means (in this case) you're drinking the entire thing between 14 and 17 days of roasting. 14 days is typically a good point, sometimes less, sometimes more. The coffee I'm drinking now is better a month after roasting than it was any time previous to this and I've tried it regularly alongside two others. The pours look better and taste better. I never got on with Rave myself and would suggest you try another roaster, probably Dark Arts, Crankhouse or Cartwheel.


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## Mrboots2u (May 10, 2013)

PD2020 said:


> Hi,
> 
> Today's shots with a well-rested, popular, darker chocolatey roast.
> 
> ...


 None of these visual clues are relevant , what the puck comes out like , jumpy grinds , guessing at puck permeability ,

Try a different roaster


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## Xabi17 (Jun 1, 2020)

Are you sure you like coffee 🤣


----------



## PD2020 (May 27, 2020)

Hi Rob1 and Mrboots2u,

thanks for your feedback.

It seems this particular problem with Chatswood was me overdosing the VST 18g basket. I noticed that If I put 18g of coffee in, it touches the shower screen upon locking in. I went down to 17g and now getting more balanced shots with Rave Chatswood. There's still room for improvement to get the most out of this bean though.

For now I've got something drinkable at 17g in, 51g out, grind setting 11.5. More Chatswood is resting and it seems I can get this one dialed in at 1:3 and likely at lower ratios too 

I imagine insufficient headspace could have been an issue with my other beans in the past. I was blindly assuming that 18g always fits in VST 18g, but that's not true, especially given how the puck expands during preinfusion.



> Just refresh my memory: are these shots still sour when diluted in water or not?


 @Rob1Yes, they are. When I get a sour shot, then diluting it with bypass water doesn't fix it.



> Are you tamping multiple times or tamping really hard?


 @Rob1 I'm back to one gentle doorknob tamp now. Trying to stick to the basics.



Rob1 said:


> Oh and another thing I've noticed is how quickly you go through coffee making minor adjustments. The 250g bag isn't even going to last three days which means (in this case) you're drinking the entire thing between 14 and 17 days of roasting. 14 days is typically a good point, sometimes less, sometimes more. The coffee I'm drinking now is better a month after roasting than it was any time previous to this and I've tried it regularly alongside two others. The pours look better and taste better. I never got on with Rave myself and would suggest you try another roaster, probably Dark Arts, Crankhouse or Cartwheel.


 Absolutely right. With some coffees I haven't experienced more than a handful days. Thanks for reminding me that coffee taste changes over time and the peak time can be a month after roasting.



Rob1 said:


> try another roaster, probably Dark Arts, Crankhouse or Cartwheel.


 I have placed an order with Crankhouse so looking forward to try them out  Thanks, @Rob1.


----------



## PD2020 (May 27, 2020)

Mrboots2u said:


> None of these visual clues are relevant , what the puck comes out like , jumpy grinds , guessing at puck permeability ,
> 
> Try a different roaster


 Can't wait to try Crankhouse next. I've also had some decent shots with Rave Chatswood now - getting there  Thanks for helping out, @Mrboots2u.


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## Max35111 (Oct 3, 2020)

Hi there, i haven't read the entire threat so that might have been discussed already, but in my case water made a big difference.

I am in London as well and thought the filtered water from my fridge would do the trick. Well, it didn't. I bought the almighty Volvic water (that comes from where I come from, so even better!) and shots were substantially better as a result. Took care of most of the sourness.


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## jonasy (Aug 12, 2020)

Have you tried say popping down to Monmouth, try an espresso and buy one of their bags? I'm a bit sceptical about the decaf coffees (maybe I shouldn't)


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## PD2020 (May 27, 2020)

Max35111 said:


> Hi there, i haven't read the entire threat so that might have been discussed already, but in my case water made a big difference.
> 
> I am in London as well and thought the filtered water from my fridge would do the trick. Well, it didn't. I bought the almighty Volvic water (that comes from where I come from, so even better!) and shots were substantially better as a result. Took care of most of the sourness.


 Hi @Max35111. Yup, we've tried Volvic but it seems to be something else  Cheers.



jonasy said:


> Have you tried say popping down to Monmouth, try an espresso and buy one of their bags? I'm a bit sceptical about the decaf coffees (maybe I shouldn't)


 Hi @jonasy. I haven't had Monmouth for a longer while now  Can't wait to try them on my MaraX but still got plenty of coffee from Rave and Crankhouse to work through  Thanks!


----------



## PD2020 (May 27, 2020)

Hello. Here's another couple of observations that maybe will give somebody an idea what's happening here...

Back around early September I had great clean smooth shots from HasBean Finca Chorrera Decaf (notes: cherry drops). The beans were super easy to dial in, very forgiving across a wide range of grinder settings, clean, the texture of the shot was silky smooth. My best shots were:

18g in, 41.5g out (ratio 1:2.3), Niche setting 11, temp 93-94*C, flowing time 24s, I didn't note the total time back then

Couple of weeks ago, just before HasBean removed this coffee from their website, I ordered another bag of 250g. Today I tried 3 shots:

18g in, 42g out, Niche setting 11, temp 93-94, flowing time 19s, total time 25s, score 1 out of 9 (HARSH + sour + bitter)

18g in, 41.5g out, Niche setting 10, temp 93-94, flowing time 28s, total time 36s, score 1 out of 9 (HARSH + bitter)

18g in, 42.1g out, Niche setting 10.5, temp 93-94, flowing time 23s, total time 31s, score 2 out of 9 (HARSH + some citrusy notes)

Every single shot has a cloud of harshness that I can't describe. If you try to look beyond the harshness, you can just about recognise the typical coffee notes, as well as some sourness, bitterness, but they're all hidden behind this super harsh, dry, gritty, powdery, chalky texture which causes my throat to itch and my mouth to pucker. This harshness dominates the shot. I used to describe it to you all as sour/bitter but it's neither. After the shot I'm getting an aftertaste of ashtray which lingers around for up to 30 minutes.

This harshness just won't go away, even if I get the coffee notes there, which I did in my third shot...

Another observation I made a some days ago... There were two days where my shots actually tasted nice, clean and smooth and dialing in was fairly easy. I had about 7 shots with 3 different coffees - all full of flavour, and zero of that nasty harshness. The flow on the bottomless portafilter looked happier. Aha! I thought the root cause was me putting the old MaraX shower screen and the black rubber gasket in, instead of my usual IMS200 + red Cafelat setup. I don't like the stock screen+gasket, because they don't lock in at 6pm for me and many other people in the MaraX thread (weirdly @Doram and some other people reported they get 6pm easily...), but I was curious if it makes any difference. Anyway, so after the 7 tasty shots in a row, I put the usual IMS200+Cafelat back in. The shots went bad. Hmm, so it clearly must be something about the shower screen then! I put the stock screen + gasket in once again - but the shots stayed awful... Until today I've been getting only bad ones..

So no idea what caused the flip to the great-shots-mode... There's something going on that causes my shots to be easy to dial in, and then suddenly the whole setup switches to the usual harshness.

Just for the record, I've been using only Volvic for about a month now in order to exclude water as a problem. It's not.

Any ideas? This stuff is unbelievably frustrating...


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## Doram (Oct 12, 2012)

PD2020 said:


> So no idea what caused the flip to the great-shots-mode... There's something going on that causes my shots to be easy to dial in, and then suddenly the whole setup switches to the usual harshness.


 Really sorry to hear of these problems. I feel your frustration but have no idea what is going on. Personally, I am not very interested in trying many types of beans and changing often. I am not there yet, but what I am hoping for the longer term is to find few beans I like and stick with them. It is nice to have a change now and then to wake you up, but I find that alternating a few types of beans at the same time confuses and makes it harder for me to focus on small adjustments to get nice shots. I understand you tried to do that with a coffee you liked, but now you get different results. It could be that the coffee isn't the same, but how can one tell?

I did notice your temp is 93-94 (is that setting 1 on Mara X?). If you are getting harshness and bitterness, perhaps you will get a better results with lower temp on setting 0?

Sorry I can't help more, perhaps the experts will have better ideas? If I were you, when I would find a coffee I like I would hold on to it for longer, if this makes sense.

As a side note for the locking position of the PF, I just checked mine again and the stock PF with my IMS and stock baskets still lock at the 6 position (with stock gasket). My naked PF locks at a further point (5 o'clock). it's really just a matter of the thickness of the 'ears' and the space they have. if it locks without leaking, I can't imagine it has any affect on the coffee. I also wouldn't think the shower screen would make a huge difference (unless something is wrong and you are getting uneven water distribution, which I assume you would see with a naked PF).


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## PD2020 (May 27, 2020)

Thanks @Doram. That was the idea with this decaf, which was the only coffee that had really worked well for me.

At least I learned that this problem cannot be fixed by changing the grind setting. It's a bit as if somebody dumped something into my shot. Yeah, the shot might be dialed in, but that something is dominating and clouding any coffee notes (or its sourness/bitterness).


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## MWJB (Feb 28, 2012)

PD2020 said:


> Another observation I made a some days ago... There were two days where my shots actually tasted nice, clean and smooth and dialing in was fairly easy. I had about 7 shots with 3 different coffees - all full of flavour, and zero of that nasty harshness. The flow on the bottomless portafilter looked happier. Aha! I thought the root cause was me putting the old MaraX shower screen and the black rubber gasket in, instead of my usual IMS200 + red Cafelat setup. I don't like the stock screen+gasket, because they don't lock in at 6pm for me and many other people in the MaraX thread (weirdly @Doram and some other people reported they get 6pm easily...), but I was curious if it makes any difference.
> 
> Any ideas? This stuff is unbelievably frustrating...


 So the shots with the 3 beans, that gave you 7 good shots, also went bad after the 7th shot with no/minimal change in shot parameters?


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## PD2020 (May 27, 2020)

Yup.

I thought I finally had it sorted. I wasn't sure what caused the change though so I put the IMS200 back in and got a muddy shot. So I went back back to the stock screen but the shots weren't as good anymore.

I remember something similar happened back in July where I was getting okay Rave Decaf shots (okay for latte; not drinkable on their own), and then one shot with the slightly slightly coarser grind (half a step on Niche) ended up flowing longer - to my surprise. When I tasted it, it was super clean.

It's very odd that HasBean Decaf which was so forgiving at a whole range of Niche settings now suddenly is giving me this layer of harshness that I know from all the other coffees.

I don't know what to make out of it. Maybe a cleaning issue? Water dispersion problem due to some tube kinks which sometimes just work fine?


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## DavecUK (Aug 6, 2013)

PD2020 said:


> It's very odd that HasBean Decaf which was so forgiving at a whole range of Niche settings now suddenly is giving me this layer of harshness that I know from all the other coffees.
> 
> I don't know what to make out of it. Maybe a cleaning issue? Water dispersion problem due to some tube kinks which sometimes just work fine?


 Is it the same bag of roast coffee or a different batch?


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## MWJB (Feb 28, 2012)

PD2020 said:


> It's very odd that HasBean Decaf which was so forgiving at a whole range of Niche settings now suddenly is giving me this layer of harshness that I know from all the other coffees.
> 
> I don't know what to make out of it. Maybe a cleaning issue? Water dispersion problem due to some tube kinks which sometimes just work fine?


 I would go with the trend, rather than occasional & rare pleasant results.

You say you are now getting results that are generic in nature & found in "all the other coffees". This seems to be the normal state.

"Gritty, powdery, gritty, dry", sounds like grind too fine. Sourness/citrusy suggest under-extraction.


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## PD2020 (May 27, 2020)

DavecUK said:


> Is it the same bag of roast coffee or a different batch?


 Different batch. That one was from August or so, this one I bought 2 weeks ago. The symptoms of when it goes wrong all the same for all the coffees though - dryness, itchy throat, ashtray aftertaste, harshness.



MWJB said:


> I would go with the trend, rather than occasional & rare pleasant results.
> 
> You say you are now getting results that are generic in nature & found in "all the other coffees". This seems to be the normal state.
> 
> "Gritty, powdery, gritty, dry", sounds like grind too fine. Sourness/citrusy suggest under-extraction.


 I'm not sure if I'm explaining the situation well.

It's a bit like this coffee machine (or grinder, or me) is running in 2 different modes. One mode is what I imagine you experience and what happened to me this summer with HasBean Decaf. Bitterness is clearly bitter, sourness is sour - you can fairly easily understand where you are.

Another mode, the common one, is where the whole spectrum of dialing in is harsh, dry, ashy. Even 18g:90g shots still have the dryness and ashyness - it's just feels less aggressive. In this mode, talking about sour, bitter or underextraction doesn't make sense anymore. It's a bit as if you had machine that wasn't cleaned for a year. It doesn't matter what shot inputs you pick, there's a layer of burned ashy gunk coming from the dirt that clouds everything else.


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## MWJB (Feb 28, 2012)

PD2020 said:


> Different batch. That one was from August or so, this one I bought 2 weeks ago. The symptoms of when it goes wrong all the same for all the coffees though - dryness, itchy throat, ashtray aftertaste, harshness.
> 
> I'm not sure if I'm explaining the situation well.
> 
> ...


 How do you understand where you are with "bitterness", when there are multiple causes. If you think bitterness = over-extraction you are very likely wrong with respect to 18:42g.

Talking about under-extraction does make sense, because it seems to be the most common & prevailing malfunction.

If you are cleaning the machine & you know it is clean, then how can it be dirty? The most likely cause of a dirty taste (excluding bad coffee) is too fine a grind.

Have you tried going cooler in brew temp?

What is your KH currently?


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## DavecUK (Aug 6, 2013)

roasts do vary, even if done by computer


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## moppy (Oct 12, 2020)

As someone who has recently got into espresso (Gaggia Classic & Niche), this is one of the most interesting threads on CFUK to me. I'm struggling with the very same problems (sour & harsh shots) and the process of troubleshooting is so informative.


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## MWJB (Feb 28, 2012)

DavecUK said:


> roasts do vary, even if done by computer


 Sure, but @PD2020seems to be getting the same symptoms accross different roasters as well as batches from the same roaster.


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## Rob1 (Apr 9, 2015)

Have you cleaned the grinder and machine properly? Have you tasted the water from the group (warm and when it's cooled) just to check. If you're using a spouted PF soak that in coffee detergent too.

Have you changed baskets e.g. 15g moved to 18g?

Sounds to me like the grind is too fine or you're brewing too hot. Just remind me how the Mara works with regards to its settings....when you lift the lever to brew is it heating the boiler to prepare for steaming and if so are you pulling all your shots within the window before you'd see a significant increase in brew temp (something like 5 minutes?).


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## PD2020 (May 27, 2020)

I've just taken the e61 mushroom off for inspection. There's plenty of green gunk on it. What's that?

Btw, I did a Cafiza backflush yesterday. Haven't used the machine since.

Edit: I touched the gunk - it's limescale

Edit2: which descaler would you recommend for MaraX?


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## DavecUK (Aug 6, 2013)

You shouldn't really be descaling but citric acid if you must..


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## MWJB (Feb 28, 2012)

If it's limescale why is it bright green?

Where is it coming from if your water is 40mg/L KH.

If you are using boiler friendly water why are you anticipating frequent descaling?


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## Doram (Oct 12, 2012)

PD2020 said:


> Edit: I touched the gunk - it's limescale


 Am I correct remembering you said you use Volvic? Is all this from bottled water? 😨


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## PD2020 (May 27, 2020)

Doram said:


> Am I correct remembering you said you use Volvic? Is all this from bottled water? 😨


 Not quite.

I've been using this machine since end of June. Last month I've been fully on Volvic. All the time before I was using home-made water by taking Osmio water and then remineralising it with Sodium Bicarb (KH) and Epsom Salts (GH) to reach the SCAA spec KH40+GH68. I've measured my water with API Test extended to 20ml for higher precision. At some point I observed that the TDS of Osmio water implies certain values of KH and GH so I was only using TDS to inform the decision how much Sodium Bicarb and Epsom Salts to add. Output TDS never surpassed 120, normally was around 108-110.

Either way, I recommend inspecting the mushroom even if you think you're boiler-safe 😉



MWJB said:


> If it's limescale why is it bright green?
> 
> Where is it coming from if your water is 40mg/L KH.
> 
> If you are using boiler friendly water why are you anticipating frequent descaling?


 You will know more about this than me but I was assuming that my KH40+GH68 water can create "miniscule" amount of limescale as explained in Jim Schulman's Water FAQ (http://users.rcn.com/erics/Water Quality/Water FAQ.pdf, page 4, the table at the very bottom). In there he says for instance that for KH40 if the water temp reaches 120*C the maximum non-scaling GH is 63 (see the table for other combinations of KH/GH).

I don't know if my green limescale is a result of that, but that's my guess.

My plan is to stop using Epsom Salts altogether and move on to plain Osmio (and maybe later add only Sodium Bicarb). I will also be inspecting the mushroom much more often to observe the scale buildup for different waters.



DavecUK said:


> You shouldn't really be descaling but citric acid if you must..


 Yeah, I know... I thought I was boiler safe but I made a mistake somewhere. Obviously I'm going to improve in this area. My next step is to use pure Osmio Zero and see if that helps.

Citric Acid order is in progress, thank you @DavecUK. Do you think this scale is reversible?



Rob1 said:


> Have you cleaned the grinder and machine properly? Have you tasted the water from the group (warm and when it's cooled) just to check. If you're using a spouted PF soak that in coffee detergent too.
> 
> Have you changed baskets e.g. 15g moved to 18g?
> 
> Sounds to me like the grind is too fine or you're brewing too hot. Just remind me how the Mara works with regards to its settings....when you lift the lever to brew is it heating the boiler to prepare for steaming and if so are you pulling all your shots within the window before you'd see a significant increase in brew temp (something like 5 minutes?).


 Thanks @Rob1. I've been cleaning the machine and the grinder very often. I clean the grinder at least once a month, the machine - every evening. And I backflush with Cafiza each month. My portafilter is bottomless so no spouts cleaning for me.

I haven't tasted the water from the group. That's a good idea. I will do it after descaling the machine.

Basketwise I've been sticking to VST18 lately, dosing 17g-18g.

Yeah, the MaraX has the 4-5 minutes window for pulling back-to-back shots. Lately I've been avoiding this trap altogether and just going one shot a time. Then cleaning of the portafilter, basket, brush the screen and the gasket with Pallo, wait good 15-20 minutes and only then maybe try another shot.


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## MWJB (Feb 28, 2012)

TDS does not imply KH.


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## DavecUK (Aug 6, 2013)

Scale is reversible and your plans to change water formulation seem wise.


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## MWJB (Feb 28, 2012)

PD2020 said:


> You will know more about this than me but I was assuming that my KH40+GH68 water can create "miniscule" amount of limescale as explained in Jim Schulman's Water FAQ (http://users.rcn.com/erics/Water Quality/Water FAQ.pdf, page 4, the table at the very bottom). In there he says for instance that for KH40 if the water temp reaches 120*C the maximum non-scaling GH is 63 (see the table for other combinations of KH/GH).
> 
> I don't know if my green limescale is a result of that, but that's my guess.
> 
> My plan is to stop using Epsom Salts altogether and move on to plain Osmio (and maybe later add only Sodium Bicarb). I will also be inspecting the mushroom much more often to observe the scale buildup for different waters.


 Why do you keep calling it limescale?

Why not cut the Osmio water with your tap water to remineralise?

You said earlier that you were using TDS to imply KH. Just measure the KH.

https://www.home-barista.com/repairs/is-this-scale-or-oxidation-on-e61-mushroom-t51333.html


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## PD2020 (May 27, 2020)

@MWJB, so let's dig in.

I've observed this:









The blue rows are measurements of TDS, KH and GH for pure Osmio water.

The white rows are measurements of my output water after adding Sodium Bicarb and Epsom Salts concentrates.

I noticed that for Osmio Water (blue rows) having TDS of say 40, the KH and GH are always the same - 17.9 and 17.9. So I stopped measuring KH and GH, and just translated the TDS into KH/GH according to this table (blue rows).

Concentrates are made like on the Barista Hustle website (https://www.baristahustle.com/blog/diy-water-recipes-redux/) except I'm using Osmio Zero water as a base which is not exactly Zero. I basically ignored the non-Zeroness of my Osmio water but always flushed it a number of times to get the TDS as low as possible (around 25-30).

I hope you can spot a mistake in here because that would explain these issues.


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## Rob1 (Apr 9, 2015)

PD2020 said:


> @MWJB, so let's dig in.
> 
> I've observed this:
> 
> ...


 I don't understand what you've done....to simplify things with a few samples from your table:

TDS ----- KH

110 ----- 31.325 
68 ----- 31.325
114 ----- 40.275
57 ----- 40.275
127 ----- 40.275
107 ----- 40.275
116 ----- 40.275
112 ----- 40.275

I don't see any correlation between TDS and KH.

When you combine KH and GH you sometimes see a result on the TDS meter that is close to them both combined, sometimes you don't. There's no consistency. Being out by 10mg/l is significant.

Volvic will scale BTW.

The deposits are probably magnesium carbonate and dissolved copper.

Also don't ignore the fact the water from the osmio is 18mg/l KH/GH and just remineralise from there.


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## MWJB (Feb 28, 2012)

It's not clear to me what you are doing, I have no inclination to back calculate the BH recipes.

If you are adding sodium bicarbonate to pure water, then you know what your KH is because it is the sodium bicarbonate per litre multiplied by 0.6.

But, your Osmio water isn't 0 to begin with (13 to 82 TDS).


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## Inspector (Feb 23, 2017)

So how bad idea it is to use water straight out of Osmio in an espresso machine? TDS being around 18


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## MWJB (Feb 28, 2012)

Inspector said:


> So how bad idea it is to use water straight out of Osmio in an espresso machine? TDS being around 18


 You want to know the KH, not the TDS.


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## PD2020 (May 27, 2020)

Thank you all for the answers. It seems the bottom line is I need to (1) remove this green gunk (2) change my water going forward.

I'll call it a day for now and reply to your posts tomorrow.


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## Rob1 (Apr 9, 2015)

The water being Volvic shouldn't be the cause of the dirty shots.


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## PD2020 (May 27, 2020)

@MWJB, I was always aiming for KH of 40 and GH of 68. But last month - only Volvic.


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## tripleshot (Jun 3, 2020)

Don't want to hijack the thread but I was surprised to see the amount of limescale seemingly caused by Volvic. That's what I've been using under the assumption that it's good for coffee taste and good for the machine as well. Is that not the case?!


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## MWJB (Feb 28, 2012)

tripleshot said:


> Don't want to hijack the thread but I was surprised to see the amount of limescale seemingly caused by Volvic. That's what I've been using under the assumption that it's good for coffee taste and good for the machine as well. Is that not the case?!


 Read the first paragraph of the paper @PD2020 linked to.


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## DavecUK (Aug 6, 2013)

tripleshot said:


> Don't want to hijack the thread but I was surprised to see the amount of limescale seemingly caused by Volvic. That's what I've been using under the assumption that it's good for coffee taste and good for the machine as well. Is that not the case?!


 Suspect it wasn't the Vovlic but the Epsom salts....which for me should really be used for medicinal purposes under the advice of a physician, immersion pools and perhaps beer making.


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## MediumRoastSteam (Jul 7, 2015)

PD2020 said:


> Thank you all for the answers. It seems the bottom line is I need to (1) remove this green gunk (2) change my water going forward.
> 
> I'll call it a day for now and reply to your posts tomorrow.


 to put in perspective.... I think Volvic water is fine. This is 10 and 18 months of Ashbeck. Ok, not Volvic, but similar, for a much longer time than yours.

https://www.coffeeforums.co.uk/topic/30238-descaling-question-10-months-of-tescos-ashbeck-bottled-water/?do=embed&comment=471810&embedComment=471810&embedDo=findComment

on my machine now, I distil my water and remineralise with sodium bicarbonate only.


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