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Extraction discussion

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Created to divert @Zwanger and high EY argument/ discussion away from the In my cup thread.

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@Zwanger I don't make espresso so I won't try to make any points about that.

Measurement of TDs and EY gives a number but it doesn't particularly correlate to how tasty a coffee is. I brew filter manually coffee via V60, Kalita or Bonavita immersion in the main.

Some coffees I prefer at lower EY some higher. In my experience anything over 21% EY via drip rarely tastes good to me. I can get tasty brews with as little as 15%EY. I don't aim for an EY. I just brew it, drink it and sometimes measure it. The solubility of the bean largely determined the TDS\EY outcome as I tend to keep grind and all other variables the same.

A good technique will produce good coffee( decent roast assumed) at a range of TDs\EY in my experience

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Pushing to get out everything out of this coffee.  For sure it's to light for espresso, need ultra fine grind and this  is really hard to work with because if you are aggressive in PI or ramps, the flow slows down too much during pour and you get choked. The crema is really thin, but the taste is what I want for sure. If I grind coarse, I get a thick crema fluffy shot, with 15-18% EY and taste is just horrible.

 

I am using a jewelry scale and the Acaia scale, to double check everything. The dose is the same 14 g (± 0.1 variations- not shown on the Acaia).  The refraction are unfiltered and so will they remain, if you don't like it that's it, I am not a lab and I will not filter my refraction.

14g in dose remains the same, always. Temperature has no impact on EY.

Shot 1 : 14 in/40 out- 9.1 TDS = 26% EY.

Shot 2: 14 in/38 out - 9.2 TDS=  24.97% EY

Shot 3: 14in/41 out- 8.6 TDS=  25.18% EY

The variations in EY are the tweaking with coarseness on grinder. The changes are minimal, under 1 mm finer or coarser.  Shot 2 was to coarse, shot 3 was to fine. Shot 1 was almost spot on, but I believe the 1:3 ratio is to much, and should try to stop at 1:2.5 or 1:2.7

 

The spots of oil on 3rd shot tells that the grind is to fine and you start to separate to oils (no more emulsion).  The shot starts to get nasty, with a really wacky bitter aftertaste.

 

 

 

 

 

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Being a bit bored in the coffee area I have bought one of these refractometers expecting that there would be a fair chance that I would return it due to inaccuracies. I'm a bit surprised how accurate it is. One of the scales displays the  index or refraction  so it's pretty easy to check. I had thought that it might pay to generate a calibration curve for it but there doesn't seem to be any point. I get the impression that it may truncate brix readings rather than rounding but it would take a lot more tests to be sure and some more accurate scales /test fluids. This sort of suggests that it may be a bit crippled on purpose.

All like this - don't know but certain aspects of these things need to be put together rather precisely or some form of  calibration used when they are made.

;) Calibration? Probably stick with my brew water but may see if changes in that area show any differences. I don't fill my machine with distilled water.

John

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If you're not a lab, then why bother with refractometer measurement at all? How do you expect a refractometer to work if there are undissolved solids blocking light? You simply can't measure refractive index accurately if your liquid has undissolved solids in it. This is just a fact. It's not any different than just generating a random number every time you're doing a measurement. The finer the grind, the more undissolved particles in the cup, more it will distort the readings. 

Maybe you can get a centrifuge, which can be reused several times so if you're refracting every brew it will be significantly cheaper?

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You only gave two data points in your earlier post and I have no idea what protocol you followed.

The 0.38% you quote is the mean error and there were measurement that are off by 0.8. In the brew you posted above, that would be a difference of 2.5% EY.

I'm only posting for the benefit of other people reading so that they don't take your numbers seriously (I doubt anyone takes you seriously in this forum - but hey, you never know) as obviously you believe too much in everything you say.

 

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You also need to filter Aeropress brews as you get undissolved solids leaking through the sides of the filter.

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Hitting some higher extraction yield is not some feat to be bragged about - in an immersion method like Aeropress it's directly proportional to your average grind size  + how long you steep + temperature.

I was just mentioning that your protocol for measuring Aeropress brews is also wrong. I could care less about what EY you are actually hitting.

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Hitting some higher extraction yield is not some feat to be bragged about - in an immersion method like Aeropress it's directly proportional to your average grind size  + how long you steep + temperature.
I was just mentioning that your protocol for measuring Aeropress brews is also wrong. I could care less about what EY you are actually hitting.
Glad someone else has said it.

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I settled on filter papers for filtering, 5um. Ok as I'm not in a rush and not much is  needed for a test. Also have a centrifuge, hand operated but revs are revs. The filter papers will have their complications so it might be an alternative.

I'm just curious about how much the extraction changes in my drinks as I usually make them. The actual figure doesn't really matter as I am totally taste driven but it wouldn't surprise me if it's rather high.

Filtering is probably a good idea because of how these things work. Probably because they are measuring an angle of reflection off the interface between 2 mediums that have different refractive indexes and bits that don't reflect needn't have any effect on it. These units are rather small though so there may be some software jiggery pokery in them to increase resolution. Light scattering may not be a good idea then.

John

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The old brew chart used to say that extraction yield Is not an indicator of quality. It is an objective measure that needs to be put into context, then it can be correlated to subjective preference range.

Whenever you brew & dissolve coffee in water, you get an extraction yield. When the coffee tastes good to you, with that grinder & that brew method, you are likely in a range +/-2-3%EY  that will taste good to you  (if the raw material allows - you can't 'fix' poor coffee with EY, you can just eliminate brewing malfunctions that show up with EY). Beans & origins will be the biggest factor in scatter of readings (all else being the same), so you won't have a 19-20% grinder, nor a 22-23% grinder - these numbers might describe the upper limiting range, but not the full tasty span. That is why such small number/ranges are unhelpful.

So it's a very useful sanity check, if a large proportion of your brews are not good & these translate to the lower end of what you're hitting, see if you can push EY up. If the least tasty brews are the higher end, back off a bit. The numbers are most useful with a large sample of origins and only apply to a single method & grinder. Once you are dialled in, with a reasonable sample you generally find that you only need to make small & infrequent grind adjustments, which saves coffee & results in a higher strike rate of good cups. You learn that you can't go from under-extracted to over-extracted with a tiny shift in grind adjustment...it takes quite a big adjustment.

I've had tasty brews from 12-26%, but that is across a wide range of brewers, grinders & methods. There are also varying degrees of EY where things taste good, or not. The peaks of good flavour fall between troughs of not so good flavour. Generally for percolation, 12-14% can be sweet, but lack perceived acidity,  15-18% can be OK but might reveal more tart/sharp flavours in espresso, 18%+ can be sweeter than the 15-18% range, but also with more balanced, ripe fruit (rather than face puckeringly sour) acidity. Grind finer and the range can extend upwards.

Bear in mind that due to varying ways in which folk measure & describe EY readings, allow +/-1%, at least, when comparing EY from different sources...one person's 20% frequently is another's 21%.

Also grinders with wider distributions make a coarser grind, this can make for tasty EYs at lower ranges than grinders with tighter/finer distributions. A knock on effect is the these lower, tasty EYs will be a little weaker, so may need more coffee to water to bolster strength. The well known 18-22% box was determined with brewed coffee range of grinds (700-1000um average sizes) and a known distribution characteristic, based on commonly used norms in the early 20th century, determined by consumers. It was never a limiting rule, covering all methods & without the possibility for shifting. Indeed, the NCA did a limited study before the 18-22% box was determined, amongst coffee professionals that saw it cover a slightly lower range (but still with significant overlap).

For drip & espresso I can make a tasty drink with one grinder, then make equally tasty drink with another and they might be 3% apart, with the same coffee & method. Without normalising, one will be a little stronger/weak than the other, but if they both fall within preference, I can't say that it matters greatly which is the higher/lower. I would only be able to guesstimate which was which based on the grinders used & my experience with them. In short you can taste when you are in a good range, but you cannot taste a/the number.

I only ever compare like with like brews - same brewer, brew size, grinder, rough range of grind size.

You can also spoil a brew/shot, by grinding too fine & without over-extracting, because too much silt gets in the cup. If the silt doesn't especially bother you then you can push harder, I prefer a cleaner cup, so if things get silty, I'll rather go a bit coarser & if EY drops (which may not be a significant drop), I'll live with it. You can also have off flavours (woody) from grinding too coarse, even if EY is otherwise  in range.

Very high EYs (23%+) are not new, they have been in the mass market for a long time, as way to maximise output from a smaller (cheaper), limited dose. It does show that more than we are used to in specialty coffee is possible. But ultimately, if you go to a café serving 16-18% shots, that they like when tasting, you have to give them the benefit of the doubt in terms of that they are probably serving something they think/regard as "good", even if you or I prefer something different.

Edited by MWJB
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I don't know what happened to @Zwanger for him to delete his posts on this thread. But following the high extraction discussion this video from Scott Rao is a good on 

 

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1 hour ago, Bacms said:

I don't know what happened to @Zwanger for him to delete his posts on this thread. But following the high extraction discussion this video from Scott Rao is a good on 

 

Unfortunately I think if you happen to question any info on his posts , then it is taken poorly , to the point where he  justs spit the dummy out and leave. .. 


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Unfortunately I think if you happen to question any info on his posts , then it is taken poorly , to the point where he  justs spit the dummy out and leave. .. 
It's a pity as trying to follow a one sided discussion interspersed with "." can be mighty confusing.
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1 hour ago, Mrboots2u said:

Unfortunately I think if you happen to question any info on his posts , then it is taken poorly , to the point where he  justs spit the dummy out and leave. .. 

Yes that was always my problem with his posts. We never seemed to be interested in engaging in any reasonable discussion and was his posts were always in me vs. the world style but no point in trying to change anything at this point since he seems to have left 

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47 minutes ago, Bacms said:

Yes that was always my problem with his posts. We never seemed to be interested in engaging in any reasonable discussion and was his posts were always in me vs. the world style but no point in trying to change anything at this point since he seems to have left 

He is doing exactly the same thing on HB now ...just won't answer questions about his process. 


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15 minutes ago, Mrboots2u said:

He is doing exactly the same thing on HB now ...just won't answer questions about his process. 

Has he moved to the US forum to try and get someone to agree with him then? 

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3 minutes ago, Bacms said:

Has he moved to the US forum to try and get someone to agree with him then? 

They do agree with him there....


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They do agree with him there....
So long as you can convince your brain that highest extractions taste best, the information your taste buds sends doesn't matter.
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Laissez les bons temps rouler

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13 minutes ago, ashcroc said:
19 minutes ago, Mrboots2u said:
They do agree with him there....

So long as you can convince your brain that highest extractions taste best, the information your taste buds sends doesn't matter.

On the other hand it's his taste buds not yours so who can say. Also his beans, machine and grinder and some one else mentioned decent drinks over a range of 12to 26% using various equipment.

Instead of taking the post on face value some seem to think it was boasting or that he shouldn't be drinking stuff with that high an extraction.

John

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4 minutes ago, ajohn said:

On the other hand it's his taste buds not yours so who can say. Also his beans, machine and grinder and some one else mentioned decent drinks over a range of 12to 26% using various equipment.

Instead of taking the post on face value some seem to think it was boasting or that he shouldn't be drinking stuff with that high an extraction.

John

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He's perfectly entitled to drink what ever extractions he likes. But he seems obsessed to get the highest possible extraction with disregard for everything or anyone else. His refractometer protocol which he uses to justify his mega extractions is highly dubious. 

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18 minutes ago, ajohn said:

On the other hand it's his taste buds not yours so who can say. Also his beans, machine and grinder and some one else mentioned decent drinks over a range of 12to 26% using various equipment.

Instead of taking the post on face value some seem to think it was boasting or that he shouldn't be drinking stuff with that high an extraction.

John

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His measuring process is really flawed and that's fine but you can't use it to define your reason for making coffee when it's hugely flawed  in the way it's done.

Saying I make the highest EY when you aren't using and following benchmarked processes for measuring is really misleading.

If someone is brewing off the chart extraction yields then it should be ok to ask about the way it's done and how it's been measured otherwise it can set unrealistic expectations of people try to replicate.

Lastly he was unable to take any constructive criticism at all and if anything was inferring we shouldn't be drinking low EY coffee .

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