I have KR804 with Sweet burrs. I use it once a day for ~24g of coffee. I used to clean it every 3 months, then went to 4 months the last two cleans. Based on how it looks, I will probably wait 5 months next time. Everything cleaned easily, so nothing is hardening or anything.

Note: Right after cleaning it usually has .3g to .4g of retention per grind for a week or so, then to .3g to .2g per grind steadily for months. Recently, it was only retaining about .1g. As to why, I assume all crevices that hold coffee had filled. So perhaps I will use that (only retaining .1g) as a signal to clean when it happens again.

Any problem waiting 5 months or more?

Acavia wrote:As to why, I assume all crevices that hold coffee had filled. So perhaps I will use that (only retaining .1g) as a signal to clean when it happens again.

And that is why I have never opened up and cleaned our grinder. That and we weight coffee in and coffee out. Espresso tastes great with 'acceptable' (to us) retention.

YMMV

I'm not entirely sure, but cleaning on grinders with little retention doesn't seem too necessary for me. A few parts like the burr screws will gunk up, but after grinding 2 espresso's the same will happen again. Some grinders might have more build up, for example near the exit chute. In that case 5 months probably won't be frequent enough.

Once every 4-5 months seems like a reasonable interval to me. Find it quite relaxing to clean/maintain stuff like grinders.

I like to clean and restore old grinders, anywhere from 20-100 years old, and my rule of thumb is total spotless clean upon restoration, then once a year after that. If the burrs are moving and getting a layer of fines on them, they are always going to be some level of "dirty," and you get diminishing returns trying to clean them too often.