A Year's Worth of Grime

A journey inside the Braun KMM30 low-end burr grinder, a supposedly impregnable and therefore forever unclean appliance. Many coffee enthusiasts might run into this grinder in the midst of several epiphanies regarding good coffee. While not suited for espresso duty beyond the steamer crowd, this little grinder is still a step above the reviled whirlyblade. The question is, how do we keep it clean?

A Year's Worth of Grime

Sitting in the shadowy reaches of a kitchen counter, somewhere in Ottawa, lies a neglected Braun KMM30 grinder. Congealing under its impregnable, irremovable hopper. It gets little use now, having been upstaged by a fancy-pants retail grinder able to meet the demanding needs of an espresso machine.

Maybe it gets to grind for a press-pot now and then, but it has long since been discarded as a feasible solution for grind-to-order espresso. Replaced by pre-ground: the horror! the ultimate insult. Actually, the horror is in how dirty these poor little grinders get, since they don't come built for easy cleaning, or do they?


I'm not sure why I gave up so easily the last time that I peered with chagrin at my grinder, wanting desperately to clean it out properly. Oh sure: I scraped, blew, and swept it clean as best I could. Unable to get inside to the burrs, however, I knew that a boggy soup of rancid coffee oils lay caked within. I was about to try the "white rice" technique to clean it out when I had another, closer look.

Rumour is that the Braun wasn't built for servicing or regular cleaning, being disposable rather than maintainable. One look at the hopper with an aim to removing it does lend this impression, but a closer look reveals a way in: the KMM30 hopper and burr assembly will actually come apart rather easily if you try.

Here's how. All that you need are a miniature flat-bladed screwdriver, some cleaning implements, and a chair to fall into when you see how dirty your grinder really is. Please ensure that your grinder is disconnected from any power outlet before attempting to clean or disassemble it.


upper burrFirst, remove the hopper [photo right]. You really can get at those seemingly inaccessible stray grounds between the hopper and the dial. You really can remove the hopper for proper cleaning. All that is required is to carefully pull on the three snaps holding it in place, located near the center of the hopper, using your mini screwdriver. Little force is required, though I found it handy to wedge something under one side of the hopper while working on the last two snaps.

Second, remove the white cylinder that you use to select the grind setting. There are three more snaps, toward the outer edges of the dial. Push outward on these, rather than against the burr carrier if you can manage it. Before doing this you might want to dial back to zero, allowing you to mark off the position of the upper burr before removing it. I forgot to do this, though I didn't mind because I wanted to zero my grinder anyway.

Having removed the dial cylinder, you will see the upper burr carrier: a piece of white plastic that resembles the wheel of a ticker-tape label maker. In the center of the carrier are the three original snaps, which held onto the hopper.

Before removing the carrier, mark off the "click" position adjacent to the zero-stop. Failing to do so will prevent you from reassembling your burrs such that your original grind settings are preserved. The zero-stop is a tab of plastic a short distance to the left of the minimum grind setting. You will note another tab on the dialing cylinder, positioned such that it lines up with this stop when the pointer is positioned at the minimum grind setting, preventing it from proceeding further. A third tab achieves the same effect for the maximum grind setting, and is positioned approximately 165 degrees around the dial.


Got that chair handy? You are now ready to unthread the plastic burr carrier, using a long counter-clockwise turn. You will hear several clicks as you begin to turn the upper burr away from the lower burr (many more, in fact, than you would hear in adjusting the dial toward the coarsest setting). Eventually, the clicks will stop and you continue unscrewing the carrier until it lifts away from the grinder. Now is when you'll need your chair: the amount of compacted coffee gunk is enough to send any coffee lover to their knees. Now is also the point where you'll see just how mediocre the burr set within the KMM30 really is. It appears to be more adept at crushing beans than actually slicing them. There are very few cutting surfaces and they are anything but sharp.

Carefully clean/chip/chisel/hammer away all of the stale coffee from your grinder. You did remember to unplug it, correct? I found that the business end of a meat skewer did wonders for picking away at the crud. I spent some time at this task, for my grinder had gone far too long without an internal cleaning. Who knew that it was this easy to get into? I went at it some more after placing the burrs under a light for photographing, realizing that there was still some work to do.


The upper burr [above right] appears to be easily replaceable, while the lower burr [lower right] would require further disassembly. I did not pick at the white center cap or undo the remaining screws to determine the feasibility of doing so, though I may consider it if I ever get an inkling to try sharpening them. There is a fairly wide channel (some 5mm or so) surrounding the lower burr, allowing the grounds to escape. Three spurs mounted to the side of the lower burr are positioned to sweep this alleyway around and through the grounds chute, but they don't cover the space terribly well. The result is that a lot of caked grinds remain -- for a very, disturbingly very long time. I went to town on my grinder and got it pretty clean (see for yourself in the pictures).


Once you are satisfied with the spiffiness of your newly cleaned burrs, putting it all back together is fairly straightforward. To preserve your previous grind settings, when rethreading the upper burr carrier be sure to stop turning it at the point where your mark lines up with the zero-stop. You may wish to test the positioning prior to reseating the dial and hopper. Next, replace the dialing cylinder such that the pointer is aligned with the minimum setting and the stop tabs meet each other. The hopper pops back in the center and you are all done.

In my case, I was interested in resetting the zero point of my grinder. To do this, I screwed it all the way down until the burrs seized up against one other. I then dialed it back several clicks (about twelve) to prevent them from stripping when I turned it on. Plugging in the grinder and holding it away from me, I carefully spun up the burrs. No contact. Next, I slowly dialed down the burrs, spinning the motor briefly at each position, until I could hear them touching. My zero position happened to be seven clicks above the point where the two burrs physically met (keeping in mind that the few cutting surfaces raised around the circumference are fairly widely spaced).


Moral of the story is that despite commentary to the contrary, the Braun KMM30 can rather easily be disassembled for cleaning. All that you really need is a little elbow grease. Oh! the eons I have spent looking at those nasty stray grounds, trapped under the hopper; the months glancing forlornly at a dirty hopper that was difficult to clean; we'll not discuss the nightmares imagined within.

Remember: our coffee is only as good as the ingredients that we use and these ingredients depend on the cleanliness of the machinery with which we ply our trade. You'll have a sparkling clean grinder and a clean conscience to show for your efforts.{moscomment}


Dave in Ottawa is one of our grand-masters of Gaggia usage. So advanced is his muse on this topic that I hang onto every word as if it was nectar! Oh, but I do.. I do.. I do... Original photos by Dave Anderson of Ottawa, Ontario Canada - Camera unknown at this time.