Mitch, why do you prefer higher RPMs for espresso?

CwD wrote:Aha! I'm glad to finally hear someone else say they use higher RPM for espresso, been feeling like the odd man out. Any idea what they're running? I'm around 1320 right now.

vberch wrote:Mitch, why do you prefer higher RPMs for espresso?

I find that when I increase the RPM, I get a faster flow with the same grind. So I can take the grind finer than I can on a slower RPM. Since I'm usually doing lighter single origins at tighter ratios, I like being able to push the extraction finer this way.

I've heard, but can't confirm, that the burr rpm to flow speed relationship is inverse on the Monolith.

SC results on Instagram!

If someone could also give some thought on what it means for example to see a higher particle concentration for the Monolith in the 200-250 range? What it may mean in the cup for the barista who brews an espresso?

Overall it seems that both the grinders are very close in terms of distribution in the middle range, with difference in the upper low and upper high ranges.

does that mean both grinders are still somewhat unimodal? And does it say the MF produces fewer large particles?

Looks to me they are both largely unimodal and very, very even.

Sigh. Again with the sieve charts, and the inevitable speculative discussions of what sieving results mean for taste in the cup.

I think this data has to be looked at with a ton of caution. It is unclear that particle mass in different categories is what matters most (as opposed to particle shape or surface area). It is doubtful that sieving can accurately measure the mass of small particles, which tend to stubbornly cling to the larger pieces through static electricity. And if there is good data associating particular sieving profiles with particular taste characteristics, I've certainly never seen it, and I have looked around to try to find it. As much as I'm grateful to Socratic for making an effort to learn more about how different grinders perform, the first step should always be to identify what the real questions of interest are, and then choose your research method to match, rather than to say, "this data is easy to collect, so let's collect and report it even if we can't articulate what meaningful question it answers."

IMHO Socratic would do much more good for the coffee community if they ran a series of blinded tasting comparisons between the results the two grinders could produce over a variety of different coffee types, roast levels, pressure/time/temp profiles, and brew ratios. Short of that, we still don't know much about how the two grinders compare in the cup, and we are left relying on comparisons like Tom C. saying that his EG-1 mimicked EK/R120 shots pretty closely, while the Monolith Flat seems to be closer to a (very well aligned) conventional flat-burr espresso grinder in its shot style. But how big the difference is? That is anyone's guess.

[creative nickname] wrote:Sigh. Again with the sieve charts, and the inevitable speculative discussions of what sieving results mean for taste in the cup.

Yes, but, particle size distribution is objective while taste is subjective. Objective data is much easier to compare and relate.

Sure, but I buy grinders to maximize taste, not to achieve any particular particle distribution, and since no one has any clear idea how to relate the first to the second, the objective data just isn't very helpful.

Step one should be taste comparisons. If the grinders consistently taste the same then who cares what the graphs look like? If there is a difference, then particle distribution analysis might be a useful part of trying to pin down what causes the difference to occur. In the meantime this is more noise than signal.

I agree. I think if one correlates sweetness with higher extractions on unimodal grinds (unproven maybe), it helps people who are after that style of shot.

Not to say that it tastes better or worse per say! Its like asking do you want an EK for epresso or a Robur? Many shops have both probably for this reason. Imagine blinding those two grinders against each other. I bet the coffee chosen as well as the taste preference of the judge would be the deciding factor, rather than which grinder purely tastes better.

The thing the particle distribution graphs MIGHT tell people is how closely any given grinder compares with that of another (i.e. EK or Robur for example)? That is if particle analysis is even accurate in any form!

To your point though, the only thing this specific case might tell us is that the flat and EG1 MIGHT taste similar in cup and that any real difference is a result of other variables.