dfk41 Mate, you made my week end. I learned brewing from Mark. He is our brew God. Period. 😊
Both are, perhaps, party right.
Flat burrs tend to emphasise clarity, and flavour separations. Conical burrs body, sweetness, and flavour integration.
IMHO, neither is “better” than the other for brewed coffee by default, and fines alone do not determine suitability.
Roast level, brew method, burr geometry (not just “flat vs conical”), and grind size range matter more than the tiring flat vs conical discussions. It doesn’t matter is my view, although I mostly drink light and medium light.
My question is:
Did earlier conicals produce fines and wider particle distribution relative to flats ? If yes, this is perhaps no longer valid as burrs have matured now.
All grinders produce fines, and we can’t just relate them to conicals.
In filters:
If we brew Light / medium light:
The flats may give higher perceived acidity, better separation of origin notes, more transparent aromatics and can even feel thin or sharp if pushed
. However, the conicals may give a round acidity, better sweetness, still give flavour notes and an enjoyable cup. Both should extract light and medium light well. I do not think we need flats for these roasts.
Likewise, if we take medium roasts, the differences may be negligible and a super taster, in blind tasting, may struggle to pick them apart
The dark roasts are more soluble and am thinking of conicals may perform better. I don’t know as I do not drink dark and medium dark.
Mark would be able to provide a lot of data points, brewing evidence, and explain better, given his 20+ years of brewing experience and logs.
I have a flat 83 mm and take the conical hand grinder when I am on the road. I like the brew from both.
In summary, I do not think the flats burrs make better brewed coffee. It does not matter in terms of capability.