Coffee Data Science
Does Espresso Extraction Produce More Fines, Part 2?
More data!
The fundamental question at hand is whether coffee extraction causes parts of the coffee grounds to break off and produce more fines (< 100um). I wanted to make sure the fines I measured were from being broken off of the coffee and not leftover from insufficient sifting.
I started with a coarse ground, and I removed the finer particles.
I also blew off the chaff just for good measure.
Then I poured cold water into the coarse grounds. The aim was to wet sift out fine particles without causing intense coffee extraction.
I was left with wet coffee and a cup of coffee.
I dried the grounds in the over on a low temperature. 19% was removed by dry sifting, and 3% was removed by wet sifting.
I sifted one more time after drying to remove 0.69g or 3% of the coffee that was dry.
Then I pulled a shot using a constant profile.
The shot ran very fast, and I used a high output yield. If fines were produced, the problem would be exasperated by a longer shot.
The resulting grounds were very coarse.
I then sifted the particles.
I measured these separately using image processing.
The particles less than 500um had a very tight distribution again. Some of these particles might have been made from coarser particles or parts of these particles were extracted. However, in this distribution, I didn’t see evidence that fines less than 100um were produced.
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