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Mahlkonig K30 ES grind fineness

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  • Mahlkonig K30 ES grind fineness

    I recently purchased a lightly-used K30 ES second hand from a cafe. After cleaning it up, I tested it out with some sacrificial supermarket beans and found that it would not grind fine enough to produce a decent pour - even if I adjusted the machine so that the burrs were just off touching.

    I tried aligning the discs (burrs) to get them closer to parallel, by marking the teeth with pen, bringing the discs into contact briefly with the machine running, and then shimming the low spots ... but this did not improve the situation very much.

    So I purchased a new set of burrs and also a new bottom disc carrier (this is the rotating carrier).

    Now the grinder can (just) grind fine enough to produce a decent pour with supermarket beans. I am getting some fines in the cup, though. Noting that getting a decent pour from supermarket beans is the most challenging case, the K30 should be good to go when I switch over to my next home roast ... and I expect I will need to back off the grind a little.

    However I am left with a lingering doubt: my lower-end grinders can easily grind fine enough to produce a powder that will stall my espresso machine, even with supermarket beans. I would have expected that a high-end grinder like the K30 should at least match that ... so now I am wondering whether the grinding chamber/motor is out of true, or whether this is just the design limit of the K30. (Having read that the K30 is supposed to grind down to 100 micron, I am suspecting the former).

    I can't feel any play whatsoever on the motor shaft. But I did notice that if I bring the discs together such that they just interfere when rotating, and then apply lateral force to the shaft in different directions while rotating manually, the level of interference does depend on the lateral direction (N,S,E, or W) in which I push while rotating. That is making me a little suss about whether the bearings are keeping the shaft rotating on a stable axis.

    Any hints or thoughts gratefully appreciated. I expect a replacement grind chamber to run around $300-400, and a motor around $800 ... so more trial and error parts replacement is not really an economical way to go

  • #2
    Supermarket beans can vary wildly in freshness, have you tried grinding this particular bag of beans in your other grinders?


    • #3
      Thanks ninja. Yes, I have. I can produce stall-inducing dust with the same Vittoria beans in a Macap MC4, and also in an abused Gino Rossi RR65 that I rescued from a subway restaurant and reconditioned.(As an aside, can anyone *not* get supermarket beans down to a stall inducing grind with their grinder? I would have thought all reasonable grinders should be able to do this)

      The irony that this Rolls Royce of grinders just doesn't seem quite right. It *is* fast though.