Comparison – Comandante C40 MK4 vs. 1zpresso K-Ultra "Fines" Production

I’ve been using the K-Ultra more recently and have noticed the commonly reported difference in flavor profile that this provides in comparison to the Comandante c40. Presumably this is due to differences in the particle size distributions produced by these grinders. I have heard that the K-Ultra has a bit wider distribution and leans towards more fines. I had not seen very convincing proof of this though. I do not have access to a fancy particle distribution analyzer, but I do have a Shelbru Sifter taking up shelf-space. I decided to do a little comparative test between these two grinders with a medium roast natural Ethiopian (known for higher fines).

Notably, fines are typically defined as particles less than 100 microns, but for the purpose of pour-over at least, the 500 micron filter on the Shelbru seemed appropriate enough. You certainly wouldn’t want very many particles in the sub 500 micron range in your pour over. I set the K-Ultra to 7.6 clicks and the Comandante to 24 clicks and ground 10.0g of beans in each. I ran each through the Shelbru for one full minute. The sifted-out fines are shown for each below.

While it looks like a decent amount – these fines are light – I could not register them at all on my 0.1g accuracy coffee scale. The overall volume looked very similar between the two samples, and I decided to go volumetric for quantification since I couldn’t do mass. They came out very similar – each was just under ¾ Tsp using a ¼ Tsp measuring spoon.

It wasn’t really part of my goal here, but I wasn’t going to waste the filtered out coffee (the >500 micron portions). I discarded all the fines and mixed the remaining two specimens together and tossed them in the Kalita Mino. Frankly it came out a little vapid tasting. This may be because I trimmed off a little too much of the particle distribution curve that does give some nuance to the brew. This fits in with what I’ve mentioned before about the Shelbru, while it may clean up a messy grinder – for these higher end grinders it probably hurts more than it helps.

This was sufficient for me at least to say that I do not think the K-Ultra produces significantly more fines than the C40. I think that’s an important point, as low fines production is hallmark of high-end grinders and rumors that the K-Ultra produce more of these are a bit of a knock. The noted difference in flavor profiles between these two grinders almost certainly has to do with particle-size distribution (I’ve seen some unimpressive amateur analyses, but nothing of quality that I can link to for a good demonstration of this), but that difference does not appear to be a simple higher preponderance of fine particles in one vs. another.