Just went and picked mine up from post office today! Nice packaging and well designed as everyone has mentioned before me. I am just surprised that the parcel's content hasn't gone missing as the box wasn't even sealed!
I ordered the barista plus set of 200um -1000um. I didn't mind the 1100um upgrade and I think that is way too coarse for brewing, even for press.
My first Kruvey test was done on my K30 grinder for espresso. Based on the particle distribution curve I've seen, I've decided to set the screen size to 600um and 700um, mainly to check how well my grinder is doing (ie, is there a lot of boulders which may indicate alignment problem). I'm glad to find that only about 1.5g(of 15g) combined was found above the two screens. I pulled the shot using the grind at the bottom tray (<600um). It was quite subtly, but I felt the acidity was slightly less sharp, comparatively. It might've just been the dose/brew ratio since I'm using less grind.
By removing only the boulders (>600um), the crema somehow felt a little powdery, as if more fines got into my cup after the sifting process. I tried again with a second shot, and I've got the same feeling (anyone else tried this?).
For another set of espresso tests, I use the Helor 101 grinder instead and selected the 200um and 500um screens. Due to the smaller screen, it does take much longer for the grind to separate, and I had to regrind the boulders. I ended up with about 12.5g (out of initial 15g) in the middle tray. Pulled a shot. It seemed to have cleaner mouthfeel and better clarity. I think it's a good sign. What's more interesting, the lingering aftertaste felt much stronger, and has a creamy/silky mouthfeel. It was almost like a titan conical flavour profile, but less of the conical brightness.
I forgot to measure the TDS of the first shot (I have an Atago refractometer). So I did another shot using the same procedure. Ended up with 12.4g for the shot. So the process is repeatable, good news. The 12.5g dose was pulled into 31.6g in about 27s. Was a tad too long I realized afterwards. Again, I've got the creamy mouthfeel and the lingering after taste. Measured the TDS and calculated the EY%. Guess what?? The TDS came at 8.1%,but the extraction yield was 23.8%! Never had I gotten such high EY even with overextraction.
(turns out I did some error in EY calculation and it should've been 20.48 %
) It does taste slightly overextracted but is drinkable. I will have to cut back the shot volume next time, or use more grind.
Worth noting I don't believe I have removed all the <200um fines. But it's enough to make a difference and quite noticable with a few quick trials.
The next test is the Helor 101 for French Press, with 700um & 900um screen. Why the narrow range? I thought the Helor is a superior grinder and I shouldn't have any problem getting within my range. Boy, how wrong was I.
I normally grind at setting of 3.6 (3 revolution and 6 dots). Turns out that's a fairly coarse setting as others had found out. 64% of the 10g fell into the top tray (boulders).
24% fell to the bottom tray (fines). Instead of getting frustrated at the Kruve, I think the more important take-home point is how it revealed the performance of our grinders. Without it, I thought my grinder is great, but look at the fines the grinders are producing!
It also occurs to me. If your sifted grind of 600-900um tastes underextracted, you can adjust your grinder as before, but you can now also lower the gate size (to 500-900um). Vice versa if your brew overextracts.
So in a way, I think many of us are intentionally grinding coarser (with underextracting boulders) in order to compensate for the fines produced by the grinders. I then lower my expectation, using the 600-900um screen size instead. Since this is done using decaf beans, I can't make conclusive statement about the taste. But visually, the sifted ground is the most even ground I have ever seen.
I can definitely see this is an exteremely powerful tool for those who know what they want to do. It allows you to customize your grind size which is naturally impossible even with a good grinder. Takes some effort and can be fiddly, a bit messy too. But it's almost like cheating if you know what you're supposed to do..will put it through its pace though to see if it's worth it for the effort. The taste seems obvious (dont think I am hallucinating) but i need someone to properly blind test it.