InfamousTuba So, it’s not conicals vs flats that’s the question, it’s conicals & most flats vs a very, very tiny sample of esoteric grinders that have only appeared in the last few years (subsequently, rendering the question at the time of asking as moot?).
I tend to think as people seek to ascertain a solid & repeatable difference between flat & conical, the goalposts for testing will just continue to move until the test has no real world value.
EK had been in use for over 25years, at least for 4 of those (prior to this study) by Scott Rao, who has since said he reckons his EK was not typical and 90% of them don’t give similar results. He has also reported high extractions from conical hand & electric grinders (not that I have been able to replicate these).