jpender Senior Member Joined: 11 Jul 2011 Posts: 394 Location: California Expertise: I like coffee
Grinder: Kyocera CM-50 Vac Pot: S/S Moka Pot Drip: Aeropress
Posted Wed Dec 5, 2012, 1:07pm Subject: Re: Coffee Brewing Method Absorption - A few notes
Netphilosopher Said:
In fact, of contact time, brew water, grind level, and extraction...the only thing with a strong, reliable correlation is the actual mass of the brew coffee.
No strong correlation, sure, but that's not what one would expect. Those data don't demonstrate that there is not the level of correlation that would occur if extraction really has zero effect on absorption (sponge model). Like my runs, yours exhibit far too much noise to see a signal. You'd need many more data to hope to tease out (or demonstate the absence of) this small effect. I stopped after ten runs because I could see it would take hundreds to measure something that has no practical value, only coffee-geekeryness.
But think about it: If A is really independent of extraction, it would mean that the more solubles you remove from the grounds, the more water those grounds retain.
Posted Wed Dec 5, 2012, 3:04pm Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
jpender Said:
... But think about it: If A is really independent of extraction, it would mean that the more solubles you remove from the grounds, the more water those grounds retain.
Keep in mind, I set out to look for this effect. I was surprised when I didn't find it.
The simplest experiment is to brew same amount of coffee, same grind, and simply change the brew water and/or contact time.
10g coffee:100g water 10g coffee:150g water 10g coffee:200g water 10g coffee:250g water
and you could replicate these for same grind, but contact times of 60 seconds, 180 seconds, 360 seconds, and 720 seconds.
I don't have exactly all of those, but I have the essential design space mostly filled out over the history of my recording. If there was an effect that mattered, it would show up in that data, and there's just a meatball of Absorption Assimilation (from ~1.08 to ~1.4 for the aeropress brews).
If I run an extraction of 15% and one at 24% and I don't see an effect or correlation, then it is essentially meaningless. And what you said is what is happening - the solubles removed from the grounds are, in fact, replaced by water mass in the grounds.
Recall - this is a physical description model that predicts the difference between produced coffee and the brew water.
In simplest terms:
You have W and C
You mix them to get a total brew slurry of W+C
After a period of time, you drain off the P from the grounds G.
W + C = P + G (say 2000 + 120 = 1760g + 360)
W - P = G - C
So, what governs what the grounds weigh?
If it's extracted to 15%:
T = 120*.15 = 18g (makes 1760g coffee at 1.02% strength).
P consists of T=18g Water = 1742g
and G consists of Water (2000-1742) = 258g Coffee (undissolved and dissolved) = C - T = 120-18 = 102g
Change the extraction only, to 22%. The difference between W and P is still the same - 240g
W + C = P + G (2000 + 120 = 1760g + 360)
But the composition of the P and the G DOES change:
T = 120*.22 = 26.4g (still makes 1760g coffee, but now at 1.50% strength).
P consists of T=26.4g Water = 1733.6g
and G consists of Water (2000-1742) = 266.4g Coffee (undissolved and dissolved) = C - T = 120-26.4 = 93.6g
In the case of percolation (the example above) the strength in the grounds is about 1/3 the strength in the pot... so one can go and figure out that another 0.6% of coffee is dissolved, ready to drain out of the grounds, if there was some way you could.
In the previous plots - I've covered extraction from 15% to 24%. The Absorption Assimilation, as I've defined it, does not change. The produced coffee is the mass of the brew water, minus an average Absorption Assimilation multiplied by the mass of the brew coffee.
The experiment I ran consisted of three amounts of coffee and only two amounts of brew water - and significant changes to grind and contact time (3 combinations). Yet there is clearly no association with any concept of Absorption Assimilation and extraction. http://www.coffeegeek.com/images/59522/Extractvs.W-P.jpg
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Well maybe it's happening, I sure don't know, but your data in that graph aren't sufficient to demonstrate it. If they were we would be able to use it to plot LRR vs. yield and get a line with slope=1.
Posted Thu Dec 6, 2012, 6:26am Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
jpender Said:
...Well maybe it's happening, I sure don't know, but your data in that graph aren't sufficient to demonstrate it. If they were we would be able to use it to plot LRR vs. yield and get a line with slope=1.
I'm not sure I understand this suggestion. Lemme noodle on it, and if you have a suggestion I'm willing to have a look at the data.
BTW, I've specifically used the term "Absorption Assimilation" to keep it separate from LRR, because obviously there are differences in philosophy. If LRR (and IF we knew how it's supposedly calculated) were related to extraction, I still maintain that I have enough data to show that "Absorption Assimilation" is not.
I think I have the calculated yield ratio (the ratio of the produced coffee to brew coffee, P/C, which is equal to (R-A)). I'm just having a hard time seeing where a plot of LRR or Absorption Assimilation and yield or yield ratio would be =1.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Thu Dec 6, 2012, 7:48am Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
I have "yield ratio" calculated for all runs.
Yield ratio is the mass of produced coffee P to brew coffee C,
Y = P/C, also this is the inverse of Espresso Brew Ratio, or C/P expressed in percentage. For espresso, a 50% EBR means 15g of coffee produces 30g of espresso, per AndyS' calculations (15/30 = .5 = 50%) This is a Y = 2.0
By calculation, the difference between water brew ratio R (the ratio of brew water mass W to brew coffee C, or W/C) and Y is my definition of Absorption Assimilation.
Y = (R-A)
Y = P/C
Notice in all of this I do NOT mention extraction. Also notice that although I have a definition of Absorption Assimilation in this, it's mathematically derived.
In other words, yield ratio takes the discussion of Absorption Assimilation out of the picture.
If extraction has an effect on yield ratio (this is the implication that Absorption Assimilation should contain some extraction term), then we should see a slope in a plot of extraction vs. Yield Ratio.
Both Y and E are normalized by the brew coffee mass (and also unitless), so we're talking matched terms.
If there is no effect of extraction on yield ratio, then the response curve would be zero if the yield ratio is on the X-axis, or "infinite" if extraction is on the X-axis.
Keep in mind we have three different water brew ratios, which are mathematically linked to the yield ratio.
Here is the response plot for extraction vs. yield ratio:
(Click for larger image)
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Thu Dec 6, 2012, 7:52am Subject: Re: Coffee Brewing Method Absorption - A few notes
We can now go searching for things that affect Yield Ratio.
How about brew water mass?
(Click for larger image)
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Thu Dec 6, 2012, 7:57am Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
Brew Coffee Mass?
Yup, something definitely going on here, but we already knew this. Yield Ratio is normalized by coffee mass.
(Click for larger image)
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Thu Dec 6, 2012, 8:17am Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
I can also compare to see if we have a flat and narrow response plot for my definition of Absorption Assimilation ((G/C)-1) vs the LRR thinking (adding a term for Extraction - or LRR=((G/C)-1)+E)
I see zero benefit or narrowing of the variation (indicating any benefit) for one vs. the other.
(Click for larger image)
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Thu Dec 6, 2012, 8:29am Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
I can predict the produced coffee P from knowing: Brew Coffee C Water Brew Ratio R and my definition of Absorption Assimilation A
P = C * (R-A)
Predicting the produced coffee with something like LRR (with the unneeded term of extraction) - I'm not even quite sure I know how to do that.
Produced coffee would then be partially dependent on extraction (though the response plots suggest they are independent). The question would be "how much difference would it make"?
0.2 out of a brew ratio of 18 is pretty small, but not insignificant. Even with small amounts of coffee, the change in mass would be picked up - TDS ranges from a couple to as much as 7g in this experiment, yet there is no response.
This has actually been done before - it's why the brewing control chart works like it does. Absorption Assimilation is essentially a constant, independent of extraction from 13% to 26%. Mathematically, they use the same exact set of governing equations with the coffee-normalized relationship of
E = S * (R - A)
Where A is approximately 2.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Posted Thu Dec 6, 2012, 8:51am Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
jpender Said:
... but your data in that graph aren't sufficient to demonstrate it. If they were we would be able to use it to plot LRR vs. yield and get a line with slope=1.
jp: For each of these runs, I have all the critical measurements:
W C G P S I also have contact time and grind setting (Bodum Bistro Burr) but that was the primary control variable to change the extraction with a repeatable recipe.
From these, all the rest can be derived.
What do you understand to be the formula for LRR (as opposed to Absorption or my definition of Assimilation)? And what are you proposing to plot?
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
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