I have two high quality grinders by the same company. They each have different burr sizes. With the same beans, with grinder A I can grind and dose 18 grams (without the grounds touching the dispersal screen) and get a nice, consistent and tasty shot. With grinder B, I can grind and dose 19 grams--same coffee, same portafilter, same portafilter basket. I also get a nice, consistent and tasty shot.

My question is: why the difference in grounds? Why do the grounds from grinder A fill my portafilter basket at 18 grams, while it takes grinder B 19 grams to fill the basket? Is the "fluffiness" of the grounds an indicator for burr/grinder quality, or does it even matter?

FWIW, I do like the shots from one of the grinders a little bit better than the other.....

The fluffiness is a red herring. You are grinding a little coarser with the 18 gram dose, so less weight takes up the same space after tamping.

Fluffiness looks cool, but it is just fluff.

That said, less fluffogenic grinders may require more aggressive WDT.

another_jim wrote:The fluffiness is a red herring. You are grinding a little coarser with the 18 gram dose, so less weight takes up the same space after tamping.

Well, that's certainly possible, but I've dialed in each shot for each grinder where I'm getting 36 gram shot with the 18 gram load and 38 gram shots with the 19 gram load each with the exact same extraction time (via PID) and same batch of beans.

Nonprophet wrote:Well, that's certainly possible ... I'm getting 36 gram shot with the 18 gram load and 38 gram shots with the 19 gram load each with the exact same extraction time (via PID) and same batch of beans.

More than possible -- except that I have it backward --- you are getting a faster flow from a higher dose with the 19 gram dose, so it must been a coarser grind.

But I still skeptical about the fluffiness. Tamping should compress whatever fluff there is, so the seeming equal volume is a puzzle.

Not to divert the main intent of the thread, but I've always assumed when people talk about fluffy grounds they mean the opposite of clumpy grounds.

Many have posted about this or that grinder producing fluffy or clumpy grounds, and from the context of the posts it seems they believe clumpy grounds cause bad extractions, perhaps due to uneven distribution.

I think clumping is mostly a function of the specific bean and grind setting, with clumping tending to increase as moisture in the beans and fineness of the grind increase. Geometry of the grind path could also play a part, so in that sense it's certainly possible that a particular grinder will eject more clumps for a particular coffee and grind setting than a grinder with a different grind path.

I've never bought into the notion that clumps lead to poor extractions. Have never been able to taste any difference between fluffy and clumpy grounds. As Jim said, the clumps disappear when you tamp. And we've seen plenty of posts where people say that the clumps immediately fall apart when touched. I think it would take a lot of clumps in one place to mess up distribution, in which case WDT is a simple solution.

Virtually all grinder reviews mention fluffiness, as if it were indicative of grind quality; I'm crestfallen to learn that it's largely irrelevant.

What I'm hearing is that Rocky was excellent after all.

Personally I think fluffy grinds matter in terms of distribution to some extent, specifically if you do not intend to WDT/shake/etc. if you have clumps in the PF they tend to distribute in place. I can't imagine they're not slightly denser there when tamped. Maybe it matters in the pour or maybe it doesn't, but at a minimum it seems fair to say fluffy/non-clumpy is probably going to distribute more evenly taking it from grinder to tamper or just doing taps.

Otherwise it's time to dust of K3 and Rocky and save a lot of counter space!

Nonprophet wrote:Are "fluffier" coffee grounds better?

Yes.