A clean coffee grinder is the prerequisite for good coffee. Cleaning is much faster than with the espresso machine. The grinder cleaning shown here can be applied to all types of coffee and espresso grinders. Nevertheless, the manufacturer's instructions should be followed. In rare cases, cheaper espresso grinders have different guidelines.
In this text we explain cleaning with cleaning powder. Good cleaning powder you can also get from us in the shop, or from many other roasteries or grinder shops.
The new cleaning video linked below also shows how you can clean the grinding discs and the retention directly and manually with a cloth by opening the grinder.
Remove deposits and coffee oils
As with the espresso machine, it is the coffee oils that settle unpleasantly. All the nooks and crannies of the grinder are popular, but also the bean hopper. 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 grinding discs and unwanted crevices from oils and deposits. After cleaning the grinder, the coffee tastes significantly better, clearer and cleaner.
Retention
But oils are not the only problem. In many grinders there are gaps where old coffee gets stuck. These gaps are called Totraum. The English-speaking world speaks of retention, meaning the coffee powder that remains. The coffee is already ground, but then doesn't come out of the grinder. Typical places are, for example, the area in front of the flapper, in the discharge chute or around the grinding discs. The flapper is designed to free the ground coffee from lumps, but can also have a clogging effect.
We distinguish between permanent and temporary retention. Permanent retention is filled once with ground coffee powder, but then no longer exchanges itself with each grinding. So it becomes old in the grinder unless the grinder is occasionally opened and cleaned. Temporary retention contains coffee powder that is already carried out of the grinder during the next grinding.
Clogged coffee behind the flapper of a Quamar M80e.
Why is retention a problem at all?
The coffee is in ground form in the grinder. This exposes it to oxygen and it oxidizes faster - in other words: it ages faster and tastes different after just 30 minutes and noticeably worse after an hour. When unground, the coffee bean itself is like a protective layer for the coffee. Grinding increases the surface area, which also accelerates aging. Every small particle is exposed to interaction with oxygen (and possibly light).
The coffee in temporary retention is carried out with each new grinding. Whether this portion of coffee beans has a noticeable or strong influence on taste depends on the timing of the last grind and the size of the retention. In our large test of over 24 espresso grinders for home use, we therefore examined retention in particular.
For example: 2 grams of retention on a double espresso made with 18 grams of coffee play a lesser role. If the retention holds 9 grams, the espresso is sourced half with old coffee.
Permanent retention plays a different role. Although the settled powder is not released again with each extraction or has no direct influence on extraction, here there is coffee powder reacting with the environment that ages in the grinder. This affects hygiene in the grinder. Coffee powder doesn't normally mold, but it does create a rancid "atmosphere". Freshly ground coffee comes into contact with it and practically rubs against the old coffee.
Does the coffee in permanent retention have a sensory influence? Yes, and quite considerably! You can do this test yourself. Extract 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, extract 18 grams again. And now brew two double espressi. And then compare the results.
By the way: the size of temporary retention often also affects the consistency of the espresso grinder or coffee grinder. With some extractions more powder remains and with subsequent ones more is dispensed.
The cleaning
- Remove and empty the bean hopper.
- Grind all remaining beans in the chute. If necessary, reattach the bean hopper because some grinders won't grind otherwise.
- Add one heaping tablespoon of cleaning powder to the bean chute. Yes, many manufacturers recommend much more. But they also want to sell their cleaning powder. We believe that 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 a portion of coffee to remove all traces of cleaning powder.
You can also learn more about this 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 used frequently in a shared apartment or office, increase the frequency. In gastronomy, we recommend adding grinder cleaning twice a week to the cleaning schedule.
Is cleaning with grinder cleaner necessary if I disassemble and clean the grinder?
Manual cleaning by opening the grinder and removing the coffee powder from the retention is more thorough than cleaning with grinder cleaner. So it can be done as an alternative.
