samuellaw178 wrote:I think there's a threshold for a particle size to be considered dead weight, and that number likely starts around >600 micron for a percolation time of 27s+ (based on what I see so far & some of my likely-inaccurate intuition).
Seems logical. But I have no way of verifying. Also, my guess is that 600uM specs do extract, only their centers remain under-extracted and for larger ones - dry. So it would be a percentage of their mass.
So my guess it that per coffee (and how stale it is) and per grinder (and alignment and burr sharpness) - there should be a dose correction factor.
I understand what you meant by longer percolation should've yielded higher extraction. But what actually happen more often is you start getting mini dead areas within the puck (sometimes not visible even with a bottomless pf).
Okay - but since the time of contact with the water increases - that should compensate (I'd think). The puck becomes a soup.
I can imagine a different mechanism at work - if water doesn't flow - perhaps it doesn't emulsify the oils - and that, in turn, doesn't allow some of the more stubborn solubles in. TDS then does down. I guess flow rate may be important as well and the reason stuck pours are horrible (underextracted).
This reminds me of an argument with the refractometer crowd about emulsions and how (they claim) that the refractometer should ignore the emulsion (which I found odd at best). I remember thinking that a corollary is that if you measure mayonnaise the refractometer will only measure the egg component... Very odd.
This lowers the effective dose, borrowing from your dead dose weight concept. So percolation science isn't really just about particle size & extraction, but also the packings. Maybe boulders do play an important structural role, as the Italians had alluded long ago, in preventing the finer grinds from creating dead area themselves.
That latter part is what my interpretation of the Craft and Science of Coffee book seems to suggest. That the role of normalization is not just handling fines - but how the density is controlled in the puck. A good grinding will have the fines either as agglomerates or affixed to larger particles. Doublehelix calls this "fractal" organization of grinds. I likened this to a pile of cocoa covered balls.
I'm using Coffeetools too. My EY numbers are slightly lower because I've set the moisture and CO2 to 0%. My understanding is these settings sometimes varied among different Coffeetools version. I only take the numbers for internal checking so not a problem.
Ah - good to know. As for the reasoning above - I think it the actual numbers matter little...
Scraping away (slowly) at the tyranny of biases and dogma.