Every time that I grind with my K30 I have to break up the clumps before tamping. I use a straightened paper clip to do this and I am getting tired of it. Perhaps I am too anal about this. Gary Horne at Mahlkonig apparently doesn't think it's an issue for me but is quick to respond to Baristas that complain about the problem. My local dealer says that the clumping is not a problem because they break up easily when they are touched with a tamper. Other than the clumping the grinder is great but I don't know if I should forget about it or sell it and buy another brand.

Anyone experiencing this with their K30? Mine was purchased in September '09 and was new.

This post from Dan Kehn about the Macap MXK isn't directly related to the K30, but clumping in general and challenges the idea that seeing clumps is necessarily a good diagnostic of potential problems in the puck... Mazzer Super Jolly vs. Macap MX vs. Macap M4

So have you tried just tamping without breaking up the clumps?

Personally, I've come to believe clumping (or as Greg Scace referred to it at one time - particle accumulation) is overrated. The grinder has already ground the beans, so the clumping (or absence of it) is not changing the particles, and tamping will no doubt get rid of any clumps.

Is it just an aesthetic issue for you, or are you suffering bad pours? Also, is this happening on beans of different blends, roasts, suppliers or are you only using one type?

On a side note, my Macap M4D clumped a lot when I first bought it but doesn't anymore. I'm guessing the burrs broke-in after X pounds of beens had passed through. Perhaps your grinder's clumping will lessen after a sufficient amount of beans have passed through the burrs, or at least I hope so.

Good luck.

I think you are probably correct. The clumps actually fall apart as soon as anything touches them. I can use anything and spread them out easily. Now that you mention it doesn't seem to be as big of an issue as it was when the grinder was new. I am dealing with a new espresso machine right now and adjusting the dose and tamp to get the pours correct but they are in the desired shot time range. I use Redline consistently.

Thanks for your input. You have helped.

Yes and frankly there doesn't seem to be any difference. I really can't see that they clumps affect the quality of the shot at all.

JohnB. wrote:So have you tried just tamping without breaking up the clumps?

cafeIKE wrote:Clumping may turn out to be the topic of 2009. I've read mountains on how clumping causes channeling, but never found one single technical proof. Try to pick up a clump. It collapses into nothing.

FWIW, clumping seems worse at the cusp of too coarse a grind. Try grinding finer, don't overdose, ensure the distribution is relativley even and your tamp is level.

from Starting out with Vibiemme Domobar Super

Unless the clumps are very big, and mainly, are DENSE, then don't worry about them. If you distribute before you tamp, they'll melt away, and if you just tamp right out of the grinder, the tamping will take care of it.

If you're worried about it while getting the new machine dialed in, for consistency purposes, you could use the WDT until you're dialed in, and then go back to just grinding right in the PF, or not.

It also might be that, even though its not a problem, the coffee you are using, in your situation, clumps a bit. Try some different blends and see what happens.

I too have experienced clumping with the K-30. We had one at our roaster in preparation for the 2008-09 competition season. However, the clumping was so bad we just didn't use it. I ended up using the Anfim at the USBC. However, this season we had the chance to use the twin which has a new motor and a new insert which distributes the coffee differently. This solves the clump issue entirely. As a matter of fact, I loved it so much I used it this year over the anfim, a doserless major and a doserless robur. It added this incredible pillowing body to me espresso. Very awesome. I will be using a k-30 at the USBC this year. Fantastic grinder!

You might try Juanjo's mod:

Improving Mahlkonig K30 "clumpiness"