KRUVE sifter - First impressions - Page 7

Grinders are one of the keys to exceptional espresso. Discuss them here.
Schalicto

#61: Post by Schalicto » Feb 03, 2017, 9:55 am

And they sent me the wrong package. I Early Bird backed on day 1, they billed the wrong amount and offered to upgrade me to the coffee geek level for free, I agreed. I should have received 4 sieves and only received 2. I've already emailed them, but I have not heard back... I'm sure I will hear back, but at the moment I'm just complaining. :|

CathyWeeks

#62: Post by CathyWeeks » Feb 03, 2017, 10:02 am

So, I ran into an interesting conundrum. I apparently grind my coffee too coarsely for the Kruve to work as intended. I keep my Lido 2 set on a +25 (or 1R+9), and I get a very similar grind in my handground on a 6 (out of 8 ). The latter is within the range the Handground recommendations for a percolator (ie, they recommend a 6, 6.5 or 7) as I'd found the 7.5 or 8 setting which they recommend for french press to be too coarse. Either way, I use a pretty coarse grind. (edited to add: From my research, however, my grind settings are not at all out of the ordinary).

That results in a grind where the vast majority stayed on top of the first (and biggest) screen. By majority, I mean that out of 40 grams, 36 remained above the top screen. Approximately 2 grams went to the bottom, and approximately 2 grams were between 1100 and 800 microns in size

I ended up discarding just the "fines" and using both the boulders and the small amount of grounds that fell in between. (I used quotes around the word fines, because in this case, it's any particle size below 800)

It is definitely a cleaner, less bitter cup, but a tad weak. So I'll probably need to go down slightly in my grind size or use a bit more coffee, or brew a bit longer. We'll see what works.

But, I'm very much hoping the Kruve guys will develop some more screens, on the bigger end.

The situation is particularly disappointing, because one of my main plans was to use it to evaluate my grinders, on how they perform on the coarser end, an area that most grinders have difficulty with. I'll still be able to do that, to some extent - like the amount of fines produced will still be measurable, but NOT the consistency of the grind itself.

Don't get me wrong. I think it's been spectacularly well-designed, but the lack of screens for the bigger end is definitely a failing (but I think it's a correctable one). I'd be happy to spring for a few more screens.

jaredw

#63: Post by jaredw » Feb 03, 2017, 5:07 pm

CathyWeeks wrote:
That results in a grind where the vast majority stayed on top of the first (and biggest) screen. By majority, I mean that out of 40 grams, 36 remained above the top screen. Approximately 2 grams went to the bottom, and approximately 2 grams were between 1100 and 800 microns in size

I ended up discarding just the "fines" and using both the boulders and the small amount of grounds that fell in between. (I used quotes around the word fines, because in this case, it's any particle size below 800)
This is what happened to me. I tried to reduce the grind but per my post on the last page. I got a very over extracted cup.

CathyWeeks

#64: Post by CathyWeeks » replying to jaredw » Feb 03, 2017, 6:57 pm

Well, I'm certainly up for playing with reducing the grind to their recommended sizes, but I'd also have to radically reduce my brew time, and possibly reduce the amount of grounds used.

What brew method did you use? (I was using my Duo, which is an immersion brew, so use a coarse grind and a long-ish brew time).

Even if I can get a good, or even better cup of coffee by reducing the grind size, and reducing the brew time, it seems strange to have limited the upper end so much. I mean, FP is an extremely popular brew method.

borisblank

#65: Post by borisblank » Feb 03, 2017, 8:06 pm

I will admit that I gave immersion brewing a shot with everything sifted > 400um with the Clever (~75% by mass), wherein I let it steep for a good 5 minutes before drawing down and was pleasantly surprised. Someone else mentioned their FP improved as well. Maybe this is where it's helpful, rather than my V60 or Phoenix 70.

jaredw

#66: Post by jaredw » Feb 03, 2017, 8:40 pm

CathyWeeks wrote: What brew method did you use?
I was using a v60.

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redbone

#67: Post by redbone » Feb 03, 2017, 8:57 pm

If someone is going to go through the step of using the Kruve sifter I think they should also ensure that their basket holes are also uniform. There has been recent testing regarding the weak link in espresso making namely non-uniform basket holes.
Between order and chaos there is espresso.
Semper discens.


Rob
LMWDP #549

samuellaw178
Team HB

#68: Post by samuellaw178 » Feb 04, 2017, 3:52 am

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! :D

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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. :shock: 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). :shock: 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.

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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.

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AssafL

#69: Post by AssafL » Feb 04, 2017, 5:11 am

samuellaw178 wrote: 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!
Is it a function of the grinder or the beans? Perhaps you are using beans roasted to a bit past 1c (city + to FC+) and grinding beans that are less than a fortnight after roast? At which case they will be more brittle than elastic.

Try using stale beans (to try to deduce if the grinder is good).

I really like your test result getting a EY of 23.8% with mild overextraction. That is the logical expected outcome of better normalization.
Scraping away (slowly) at the tyranny of biases and dogma.

samuellaw178
Team HB

#70: Post by samuellaw178 » replying to AssafL » Feb 04, 2017, 10:15 am

Hi Assaf,

That's an excellent point, I didn't think about it from that perspective. I think it is both the function of the grinder and the beans. The decaf that I used was old (1 month+, something I didn't really want to finish...), but it's decaf after all which may be a bit more brittle than usual. I don't think using stale elastic beans to check the grinder would be a good idea...since that won't be representing its normal expected performance.

I was quite surprised by the EY% actually. Visually, the bottomless pull looked a tad less steady than unsifted ground. Plus the flow rate was my regular flow rate,maybe even a bit faster, and I was using the dialed-in grind setting (no change there). My guess though, is the EY% gain mainly came from the removed boulders (4g before I regrind them at the same grind setting).

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Sorry guys, off topic discussion below..
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Also, I did read your previous post and the linked thread about grind normalization. I drafted a response but deleted it because there's a whole bunch of jumbled ideas in my brain and they're not very organized at the moment. :oops: In short however, I think the normalization is more important for large-scale production to ensure quality consistency, though the concept can be applied to individual shots, where some form of mixing is used to ensure the entire coffee bed is homogenous. My opinion is the homogeneity of the coffee bed is the most important factor to ensure even flow or water tortuosity through the entire puck. The role of fines are secondary or is only a byproduct.

Some grinders do better (we have to specify what is 'better') than the others because the designer actually gave thoughts into the chute design that promotes good back-mixing. K30's new silicone flap and Mythos's clump crusher are two that come to mind. Post-grind mixing really makes a whole world of difference in my opinion. Of course, a tighter grind distribution will require less back-mixing to achieve a homogenous puck. By trying to single dose the K30, it's obvious that the silicone flap was less effective in homogenizing/normalizing the puck. Grinder like EK43 seems to extract higher because its largest average grind size is much smaller as compared to other grinders such as Robur (which has probably 20-30% coffee in the boulder territory). That is probably another story on its own too, as I don't quite buy the idea that a wider particle distribution is always a bad thing. It depends on what you're trying to achieve. Urm, did I mention that I tried to keep it short. :oops: