# Scott Rao - Refracting Coffee



## The Systemic Kid (Nov 23, 2012)

Scott Rao explains why refractometers are helpful.

Thanks to @the_partisan for drawing attention to part of this video in the Aeorpress thread.

[video=youtube;tiqjf8-yuR4]


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## Jason1wood (Jun 1, 2012)

Interesting viewing.

Think I'll have to get myself one soon.

Any help is most welcome as not sure my palate is tuned enough to tell if I'm consistent enough.


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## 4085 (Nov 23, 2012)

Jason, if you enjoy, or think you enjoy the drinks you make, why bother buying an

Expensive rubber stamp, especially if your palate is not highly tuned. The stats

Say the drink is perfect but your palate lags behind


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## Obnic (Jan 14, 2014)

See if you can borrow one first. They're an expensive brick if you don't use it. They do really push your coffee making forward though if you do commit. It can make you quite frustrated with your grinder though if it's holding your TDS back.


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## The Systemic Kid (Nov 23, 2012)

Jason1wood said:


> Interesting viewing.
> 
> Think I'll have to get myself one soon.
> 
> Any help is most welcome as not sure my palate is tuned enough to tell if I'm consistent enough.


Refractometer doesn't ensure good coffee but it provides invaluable data in respect of standards like the SCAA. You can then see if you like, say, 20% EY or if you prefer something a bit higher or lower. So a VST helps achieve better consistency.


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## jlarkin (Apr 26, 2015)

dfk41 said:


> Jason, if you enjoy, or think you enjoy the drinks you make, why bother buying an
> 
> Expensive rubber stamp, especially if your palate is not highly tuned. The stats
> 
> Say the drink is perfect but your palate lags behind


I have to say I haven't actually found the refractometer that useful for espresso brewing with an EK, but that said, the reason I bought one isn't to satisfy myself that I'm brewing correctly to start with. I think it's more a question of if you're satisfied with making a coffee which tastes good to you in that moment or if you're interested in seeing if it could perhaps taste even better? I didn't know I liked X, Y or Z thing until I'd tasted it (I'm thinking beer that's not mass produced, more interesting whiskey, steak cooked really well etc).

Also for brewing filter coffee I find it invaluable, because I still can't tell what's wrong with a brew just by taste alone but with a refrac I can see if it reads under or over and then adjust and it always tastes better. Even if that's in my head, I don't care, because it still tastes better.


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## mathof (Mar 24, 2012)

dfk41 said:


> Jason, if you enjoy, or think you enjoy the drinks you make, why bother buying an
> 
> Expensive rubber stamp, especially if your palate is not highly tuned. The stats
> 
> Say the drink is perfect but your palate lags behind


Your palate is not fixed at its current state. I've been using a refractometer for a few months now. At this point, I can pretty accurately guess the TDS of an expresso formula I use daily, by tasting a cup and then measuring the sample I had previously put aside. I doubt that I would have registered as many flavour details before I began this process.

The stats don't say the drink is perfect, just that it has a particular Extraction Yield. You have to decide for yourself what is the best EY for the particular coffee you are brewing.

Matt


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## Mrboots2u (May 10, 2013)

mathof said:


> Your palate is not fixed at its current state. I've been using a refractometer for a few months now. At this point, I can pretty accurately guess the TDS of an expresso formula I use daily, by tasting a cup and then measuring the sample I had previously put aside. I doubt that I would have registered as many flavour details before I began this process.
> 
> The stats don't say the drink is perfect, just that it has a particular Extraction Yield. You have to decide for yourself what is the best EY for the particular coffee you are brewing.
> 
> Matt


Plus one


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## 4085 (Nov 23, 2012)

I watched the first ten minutes of this video. My impression was that in a busy retail environment, it is a must have piece of kit. How home use, you have to be a die hard to spend £750 then £65 for 50 filter things to measure with, all for making 2 to 5 coffees a day. I appreciate you do not measure every cup you make, and I also appreciate that the information it gives may be invaluable.

Lots of people enjoy cooking to a high standard at home, but how many people have their gas cookers taken out and a professional cooking range put in?


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## Jason1wood (Jun 1, 2012)

dfk41 said:


> Jason, if you enjoy, or think you enjoy the drinks you make, why bother buying an
> 
> Expensive rubber stamp, especially if your palate is not highly tuned. The stats
> 
> Say the drink is perfect but your palate lags behind


I understand that David but when I had that coffee at yours, it was miles better than what I'm able to achieve and we discussed I could do with advice as how to get the best out of my gear, and then to keep it constant.


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## Glenn (Jun 14, 2008)

@dfk41 @Mrboots2u I will be tidying up the irrelevant posts from this thread


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## Jason1wood (Jun 1, 2012)

Here's something I read which I hope explains what I was trying to say earlier.

The difficulty some people have in determining whether an espresso is under-extracted or over-extracted is one reason that a coffee refractometer is a great learning tool for many of us with less-than-superior cupping ability.

Took this from some reading on HB, it explains I even have trouble determining slightly sour or slightly bitter.


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## foundrycoffeeroasters.com (Jun 19, 2014)

Fwiw, the refractometer for me is nothing other than a way of sticking a pin in a map. If I make a brew and it tastes great at 18%, then that's where the pin goes. I tend to try not to change recipes much so I'm just after TDS to shoot for. I may use the knowledge that having the refractometer gives me (ie that there is potential to extract a lot more from the coffee) and I may push harder, which may or may not lead to me finding something tastier but 9 times out of 10, I'll end up accepting that 18% is what I like for that bean, but I can relax knowing that I've probably not missed out on something better.

Actually, it's never 18%, but it's very often 20% and rarely above 21%.


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## Mrboots2u (May 10, 2013)

Jason1wood said:


> Here's something I read which I hope explains what I was trying to say earlier.
> 
> The difficulty some people have in determining whether an espresso is under-extracted or over-extracted is one reason that a coffee refractometer is a great learning tool for many of us with less-than-superior cupping ability.
> 
> Took this from some reading on HB, it explains I even have trouble determining slightly sour or slightly bitter.


I think where it breaks down sometimes is that people are scared of using one or having their coffee termed " nominally under/over extracted "

The terms are only really relevant to an individual if they see a taste imbalance and they want to change the results.

Sometimes i think that people are concerned that a number, a EY % dictates what a coffee should be, and i see alot of blogs and posts on HB that do infer that " coffee has to be 20% ", and i find those just as rigid and misleading as posts that say " a refractometer shouldn' taste for you "

As Lee says it's a pin a marker ...


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## MWJB (Feb 28, 2012)

foundrycoffeeroasters.com said:


> Fwiw, the refractometer for me is nothing other than a way of sticking a pin in a map. If I make a brew and it tastes great at 18%, then that's where the pin goes. I tend to try not to change recipes much so I'm just after TDS to shoot for. I may use the knowledge that having the refractometer gives me (ie that there is potential to extract a lot more from the coffee) and I may push harder, which may or may not lead to me finding something tastier but 9 times out of 10, I'll end up accepting that 18% is what I like for that bean, but I can relax knowing that I've probably not missed out on something better.
> 
> Actually, it's never 18%, but it's very often 20% and rarely above 21%.


All your examples are nominal extractions, the problem for a lot of folk is, without knowing where they are on the map, they can be making incorrect assumptions based on taste (e.g. 'bitterness means I'm over-extracting') & not reliably, if ever, hitting a nominal extraction.

I find the idea of targeting a range of 1% a bit strange (the various speciality organisations all work to a 4% spread, those in the industry are often seem to be a bit more selective), considering different methods & typical brewing variances. The idea isn't really to, limit yourself to a tight range, but brew, taste record.

With drip I tend to aim to get 18-22% (& hit it for the same method & similar brewers for the last 57 brews straight - so another use can be to assess your brew/brewer consistency), if it tastes good anywhere in there I'm happy...if I think there's more to come/less will improve the drink, I work a bit harder targeting that.

For declining temperature immersions I aim for as much as I can get.

If you're hitting less than 28%EY, there is always the potential to extract more from the coffee.

Nowadays I find myself faffing with recipes & methods much less, the refractometer & software has helped me determine what tangibly affects the brew (for a given method) so I spend more time drinking good coffee, less chasing red herrings. It also helps no end in discussing recipes (not just brew ratios) with others.


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## UbiquitousPhoton (Mar 7, 2016)

So, would the Atago refractometer be acceptable as part of the learning process, or does it totally have to be the VST?

I really wish someone would rent these...


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## Mrboots2u (May 10, 2013)

UbiquitousPhoton said:


> So, would the Atago refractometer be acceptable as part of the learning process, or does it totally have to be the VST?
> 
> I really wish someone would rent these...


 @Glenn used to .. problem is you need coffee tools and if using for espresso filters ( which are bought by the 100 and are £1 plus each )

So your looking at insured postage to and from ( for a 600 quid item ) plus filters at £1 plus a go ...Plus some cash to whoever's it is


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## Glenn (Jun 14, 2008)

UbiquitousPhoton said:


> So, would the Atago refractometer be acceptable as part of the learning process, or does it totally have to be the VST?
> 
> I really wish someone would rent these...


Yes the Atago refractometer is acceptable.

If using both that and the VST then use the same for consistency


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## Jason1wood (Jun 1, 2012)

To be honest, a ball park figure would suffice for me and trying to keep it consistent would help me massively.

I enjoy the coffee I drink but I know there's so much more to come.


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## foundrycoffeeroasters.com (Jun 19, 2014)

Glenn said:


> Yes the Atago refractometer is acceptable.
> 
> If using both that and the VST then use the same for consistency


Agreed. Precision much more important than accuracy. I'd be surprised if the VST was actually much more precise in reality.


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## foundrycoffeeroasters.com (Jun 19, 2014)

MWJB said:


> I find the idea of targeting a range of 1% a bit strange


This is kind of my point, I don't target any specific number, this is just usually where I end up, which is likely to be as much about the grinder as anything else. My point is that the reading is just a marker, nothing else. I'm talking about espresso which I should have mentioned. An EK is different in that EY preferences for me there tend to be higher in general, again related to what the grinder is capable of.

I had an espresso from an E10 conical grinder the other day which Callum made for me. It was the best shot I've had in ages and it was also amazing in milk. We didn't refract it but I'd be very surprised if we were over 19%


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## SmithStCoffeeRoasters (Feb 23, 2016)

What we need is a Chinese clone for 40 quid delivered


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## the_partisan (Feb 29, 2016)

Might sound it stupid, but would it be possible to somewhat measure extraction by letting all the water evaporate from the coffee, by boiling or otherwise ? You could then weight whatever is left and that would be your TDS?


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## GlennV (Mar 29, 2013)

No, not at all stupid. This is the standard way of doing it, to which the VST is calibrated (on filtered samples). The coffee isn't actually boiled, just held at a temperature just below boiling for an extended period.


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