HarveyMushman The technical grind size description for cupping (1:18 ratio, break at 3-5 min, start tasting at 8-10 min), derived in the 1980’s presumably, is around 720um avg (70-75% passing through 850um, 25-35% passing through 600um).
This is a medium pour over grind, I also use it only for the longer, insulated FP steeps. It results in low extractions for cupping. It is, however, much finer than the recent fad for coarse French press (around 900um average). 800-850um is US manual drip grind.
um/microns here is not equivalent to Kruve units.
I don’t think anyone knows now what cupping grind was for the 100yrs of cupping that preceded this & prior to the invention/common use of the French press.
‘Cupping’ however has become a loosely controlled & very variable process, especially with respect to grind, depending on who does it, so it’s very hard to know what people are doing when they ‘cup’.
