A clean coffee grinder is essential for good coffee. Cleaning it is even faster than cleaning an espresso machine. The cleaning method shown here for coffee grinders can be applied to all coffee and espresso grinders. Nevertheless, the manufacturer's instructions should be followed. In rare cases, there might be different instructions for cheaper espresso grinders.
In this text, we explain cleaning with cleaning powder. You can purchase good cleaning powder from our shop, or from many other roasters or grinder shops.
The new cleaning video linked below also shows how you can clean the burrs and the dead space directly and manually with a cloth by opening the grinder.
Removing deposits and coffee oils
As with espresso machines, coffee oils accumulate unpleasantly. All crevices of the grinder, as well as the bean hopper, are popular spots. The darker the coffee is roasted, the more oils remain. And oils become rancid under the influence of oxygen. The main goal of cleaning is to free the surfaces of the burrs and unwelcome crevices from oils and deposits. After cleaning the grinder, the coffee tastes significantly better, clearer, and cleaner.
Dead space and retention
But it's not just the oils that are a problem. Many grinders have gaps where old coffee gets stuck. This gap is called dead space. The English-speaking world refers to it as retention, meaning the residual coffee grounds. The coffee is already ground but then doesn't exit the grinder. Typical locations include the area in front of the flapper, in the dispensing chute, or around the burrs. The flapper is designed to free the grounds from clumps but can also have a damming effect.
We distinguish between permanent and temporary dead space. Permanent dead space is filled once with ground coffee powder, but then does not exchange with each grind. So, if the grinder is not opened and cleaned occasionally, it will age inside the grinder. Temporary dead space contains coffee powder that will be carried out of the grinder with the next grind.
Clogged coffee behind the flapper of a Quamar M80e.
Why is dead space a problem?
The coffee sits in the grinder in its ground state. This exposes it to oxygen, causing it to oxidize faster - in other words: it ages faster and tastes different after just 30 minutes, and significantly worse after an hour. When unground, the coffee bean itself acts as a protective layer for the coffee. Grinding increases the surface area, which also accelerates aging. Every tiny particle is exposed to interaction with oxygen (and possibly light).
The coffee in the temporary dead space is carried out with each new grind. Whether this portion of coffee beans has a significant or strong impact on the taste depends on the time of the last grind and the size of the dead space. In our extensive test of over 24 espresso grinders for home use, we therefore primarily examined the dead space.
As an example: 2 grams of dead space for a double espresso using 18 grams of coffee play a minor role. If the dead space holds 9 grams, half of the espresso will be extracted with old coffee.
Permanent dead space plays a different role. Although the deposited powder is not released with each shot or has no direct influence on the extraction, there is coffee powder reacting with the environment stored in the grinder, which ages over time. This affects the hygiene in the grinder. While coffee powder typically doesn't mold, it does create a rancid "atmosphere." The freshly ground coffee comes into contact with this, practically rubbing against the old coffee.
Does the coffee in the permanent dead space have a sensory influence? Yes, and a very significant one! You can do this test yourself. Grind 18 grams of coffee and then clean the grinder. Follow our video if you have a G-Iota/DF64 or Eureka Mignon. If you have a different grinder, follow the manual, search for a guide on YouTube, or write to us so we can make a video for you. After cleaning, grind another 18 grams. And then brew two double espressos. Then compare the results.
By the way: the size of the temporary dead space often also affects the consistency of the espresso grinder or coffee grinder. With some shots, more powder remains, and with subsequent ones, more is dispensed.
Cleaning
- Remove and empty the bean hopper.
- Grind out all remaining beans in the chute. If necessary, reattach the bean hopper, as some grinders won't grind otherwise.
- Add a level tablespoon of cleaning powder to the bean chute. Yes, many manufacturers recommend significantly more. But they also want to sell their cleaning powder. We believe one tablespoon is sufficient. In the case of our cleaning powder, that's 10 to 15 grams.
- Grind the cleaning powder.
- Reattach the bean hopper.
- Grind one portion of coffee to remove all traces of the cleaning powder.
You can find more information in our coffee courses at www.kaffeemacher.ch/akademie
Frequently asked questions about cleaning coffee and espresso grinders
How often should a coffee grinder be cleaned?
We recommend cleaning with grinder cleaner every two weeks. If the grinder is frequently used in a shared flat or office, the frequency should be increased. In gastronomy, we recommend including cleaning twice a week in the cleaning schedule.
Is cleaning with grinder cleaner necessary if I disassemble and clean the grinder?
Manual cleaning, which involves opening the grinder and removing coffee powder from the dead space, is more thorough than cleaning with grinder cleaner. Therefore, it can be used as an alternative.
