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 Thu Dec 6, 2012, 12:11pm Subject: Re: Coffee Brewing Method Absorption - A few notes
I'm assuming that LRR is defined in Mojo the same way as in the VST patent. If so, LRR = A + yield, and if A is constant then that's the equation of a line with slope=1. So you'd take your values for W-P, divide by C to get A (you could then combine data for different C), add the yield to these data, and then plot them against the yield.
In your tests, the variation in extraction itself is smaller than the measured variation in A. So if there is a proportional correlation with extraction you won't see it with a handful of runs.
Consider the middle case in your graph of extraction vs W-P. The values range from about 28 to 34 grams. That's a lot of scatter, something like ±3g. The effect of extraction on A (assuming a proportional effect) would be less than ±1g of water over the whole range.
Posted Thu Dec 6, 2012, 3:52pm Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
jpender Said:
I'm assuming that LRR is defined in Mojo the same way as in the VST patent. If so, LRR = A + yield, and if A is constant then that's the equation of a line with slope=1. So you'd take your values for W-P, divide by C to get A (you could then combine data for different C), add the yield to these data, and then plot them against the yield.
I'm still having a hard time with the slope=1 thing.
On a plot where the x-axis is extraction, and the y-axis is LRR (A+E), the slope should be 1?
For such a plot with a system that is basically A=1.16 on average,
for a 16% extraction, LRR = 1.16+.16 = 1.32 for a 24% extraction, LRR = 1.16+.24 = 1.40
I don't see how the slope will equal one if I plot that vs. extraction.
------------------------------------------ ----------------------------------------- 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
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 Thu Dec 6, 2012, 4:00pm Subject: Re: Coffee Brewing Method Absorption - A few notes
Slope is rise / run, or delta-y / delta-x. In this case:
(1.40-1.32) / (0.24-0.16)
It's so trivial you're probably looking for something more. The only reason I suggested graphing it this way is it brings into focus how much the noise dominates over the signal.
Posted Fri Dec 7, 2012, 5:30am Subject: Re: Coffee Brewing Method Absorption/Assimilation - A few notes
jpender Said:
Slope is rise / run, or delta-y / delta-x. In this case:
(1.40-1.32) / (0.24-0.16)
It's so trivial you're probably looking for something more. The only reason I suggested graphing it this way is it brings into focus how much the noise dominates over the signal.
Ah. Such a plot also shows the dominance of the constant over any effect (real or imagined) of extraction.
If I can repeat strength using the prescribed recipe that well, then adding something that is lost to noise is of little value when building a working model. It doesn't help me predict how much coffee I get given the recipe, it doesn't improve my prediction of end strength, and it confounds a parameter unnecessarily with the output. Absorption Assimilation is really only important if you're trying to use the recipe (Brew Water + Ground Coffee) and end strength to calculate your extraction on a percolation method.
By now, though, we can basically throw away the brewing control chart, and simply use the formula:
E = S * Y = (P * S) / C for percolation, (where E=extraction, S=Strength, Y=yield ratio or 1/EBR or P/C, C=Brew Coffee, P=Produced coffee)
and for immersion:
E = (S/(1-S)) * R = (S/(1-S)) * (W/C) for immersion. (W, obviously = Brew Water and R = Brew Ratio).
You can simply avoid using Absorption Assimilation if you want. For things that you have the option of how much you produce (how hard you press your AeroPress, what you do with the grounds in the CCD, or whether your French Press is filled to capacity or not and whether your filter can reach the bottom), Absorption Assimilation can be arbitrary.
Depending on how I use my French Press, the calculated Absorption Assimilation can be anywhere from 2.8 to over 5 (if I fill to half capacity with a normal-ish water brew ratio). The filter does not reach the bottom, so it makes a difference if the grounds at the bottom are 3mm deep or 15mm deep, if the plunger only goes to 20mm from the bottom.
The AeroPress can change from 1.08 to 1.4, to 1.7 depending on many other factors and keeping extraction the same - those being the bean varietal, (I think) roast level, and even the temperature of the slurry when you press it, and whether you're a "stop pressing at first hint of air hiss" or a "press like a motherscratcher to get every drop" type.
In this way, we're discussing something that can't be practically measured, and since my testing doesn't show its an effect, I consider "Absorption Assimilation" independent of extraction.
------------------------------------------ ----------------------------------------- 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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