Someone actually did a blind study comparing flat vs conical grinders with over 150 coffee professionals [0] to find they could not discern a difference in how the coffee was ground before being brewed while controlling for other variables.
So it would seem that Audiophiles are the perfect analogy.
I’d love to see what grinders and specific burrs she used.
We also setup a blinded coded triangle test, there was only 3 of us and four grinders: one $5k grinder, 2x$2.5k, one $700. 2 flat 2 conical. The flats have teeth supposedly for filter brewing. One coffee.
We picked the grinders correctly. Obviously we could have better methods, but the differences seemed obvious between the flats and conical. Within the same geometry, I think I just guessed the better tasting one to me was the more expensive grinder which may or may not be true. This surprised us. We didn’t think we’d pick anything. But all agreed on similar tasting notes for the flats and conical with no proper discussion or even looking at the notes for the coffee.
Brewing espresso I even observe psychical differences during the brew. I have two sets of flat burrs from the same grinder. Different teeth pattern. Same coating. One set allows me to go much finer to hit the same grams per second out and always leaves a soupy mess in the basket regardless of setting. The other doesn’t leave a soupy mess and grinds courser. I don’t know what’s happening. But this is easy to reproduce.
But then again, I also have a hand grinder that tastes more like my flats. And was quite cheap. So flat vs conical may not matter at all and it’s the shape of the cutting surface.
The same bean on my setup with 2 pre-weighed doses at room temp. One dose is vacuum packed and frozen over night.
When making espresso, the frozen beans straight from the freezer, must be ground finer for the same rate of output. And it tastes slightly more intense. I would guess that TDS went up but I can't prove that. All I can prove is that the space between the burrs is smaller.
This is a very different difference than between flats and conicals. If you brew for cupping, that is grinds straight in water, the conicals produce a muddier coffee. Basically more fine bits of coffee are in suspension and you can feel it.
This woman was serving up filter coffee. If she used good filter paper, and ground coffee appropriately, I can totally buy that almost all the fines were removed from the final product and no difference can be tasted.
So it would seem that Audiophiles are the perfect analogy.
0: https://youtu.be/3XYTi6OBecA?t=2400 (Discussion on the study begins around 34:00)