Knock Feldgrind excessive fines?

Coffee preparation techniques besides espresso like pourover.

#1: Post by gimpy »

I use a Knock Feldgrind grinder for my Aeropress and Clever Coffee Dripper. I have no other stand alone grinder. I decided to check the fines amount produced, by using my Kruve sifter. I have not used it in quite some time.

Anyway I used the 600 uM sifter for the fines amount. The 600uM is a recommendation from the Kruve or Knock instructions for pour over. With the setting set at just under 3 full turns on the knock, I get about 3.5 grams of fines from a 20 gram grind. That's close to 20% waste if I throw the fines out.

My question is, does that seem like an exorbitant amount of fines? I am wondering if I need to go into the guts of the Knock to see if I can do some fine tuning to maybe lessen the fines output? I have not torn into the grinder before.

Anyway, just wondering.


#2: Post by Jonk »

The aergrind is not exactly a low fines grinder. I'd advise against trying to mess with alignment - AFAIK the ring burr is press fit and you risk doing more harm than good.

To be frank there are better grinders for filter coffee in my opinion. Gotta love the form factor and adjustment system though!

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#3: Post by baldheadracing »

600um (Kruve, not laboratory, sizing) seems an awfully large number, as fines typically peak around 50um. However, small particles like fines stick together, so a large Kruve size like 400um is a practical minimum to catch fines - but that size (or larger) includes those ~100um-400um particles that aren't fines. As for whether a particular percentage is good or not, the catch is your grind setting is going to have an impact on what proportion of particles fall from ~100um-400um (or ~100um-600um, etc. Fines don't change size.)

FYI Kruve grinder comparison

If you really want to sieve, then I'd say that with a conical burr hand (low rpm) grinder, you're better off spending your time sifting just the boulders and chaff and then re-grinding the boulders.

Good luck!

As an aside, the Feldgrind is not the same as the Aergrind. The Aergrind is okay for the relatively fine grinds often used for Aeropress (kinda stands to reason). Coarser grinds - not so much in my experience.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada


#4: Post by Jonk »

Oops, seems I only read the question at a glance. Feldgrind shares the same burr geometry at least. That is my experience as well - actually think those burrs excel even finer than espresso.

gimpy (original poster)

#5: Post by gimpy (original poster) »

Thx, for your responses, bhr and Jonk. I thought the Knock would do fine for travel when I first bought it. Last year I sold my Pharos along with my La Pavoni, so it is the only grinder (besides my Zassenhaus-somewhat damaged) that I still have.

I will continue with a little experimentation with the grind size, etc. to see if I wish to just "throw away or discard" up to 20% of my grind, or take the extra time and trouble to make a cup if there is no noticeable advantage. I'm kind of a cheap ol' .... :mrgreen: :roll:


#6: Post by Jonk »

No need to throw anything away. Save the fine layer and use it separately in your aeropress or a cezve.