Hi everyone,
I frequently have to clean my Lelit pl043 grinder. Just take a look at the pics:





Is that common? I'm worried that I might end up drinking stale coffee.

I cannot speak about your particular grinder, which I have never seen in person, however:

All grinders have recesses that collect grinds in their chambers and beans which are in the process of going from the hopper into the grind chamber. In general, these recesses fill up with grinds and beans and after this occurs the newly added and freshly ground beans will move through their respective paths without a lot of mixing. This is to say that the old stuff stays in the recesses where it fills up the voids, and the new stuff makes its way without getting very much "polluted" by the old stuff. There is another issue, the grind path itself, which I'll address below.

Some people believe that constantly disassembling their grinders and cleaning them out will assure them of fresher grinds and keep their grinders sparkling clean (inside). My view on these practices is that they waste a lot of time and risk damaging the grinders, since the burr carriers tend to be made of brass which is soft, and which often threads onto steel which is not, and this can lead to "misthreading." There are commercial grinder cleaners which can be used occasionally and which I believe do a reasonable job when it comes to maintenance type cleaning. In my own practice I do this sort of cleaning with grinder cleaners about 2x a year, usually after I have been away from home for a prolonged period during which retained grinds in the burrs could be assumed to have become quite stale, but that is just my practice. The use of the grinder itself will "clean" the burrs by forcing newly ground coffee in these spaces between the burrs themselves, which will serve to clean them.

Getting back to the grind path itself, this is where one could reasonably expect, in daily use, to accumulate older ground coffee on a shot to shot basis. This will vary by the grinder and how it is to be used. If the grinder is filled up with a certain type of coffee that is not changed shot to shot, then this aspect becomes less important than it does in the case of single shot dosing, something that I do not do personally.

In my own personal practice, where I do not change coffees in a given grinder all that frequently, I will make a point of cleaning out the grinder chute as it exits the grind chamber with a chopstick, using those grounds in the current shot. If the grinder has not been used for a number of hours, such as overnight, I will go to the additional step of grinding 2-3g of grinds through the grinder at first use for the day, cleaning out the chute, and then using those grinds to clean out the doser (assuming one's grinder has a doser). This practice of cleaning out the grinder chute with each shot, and using a few grams of grinds to clean out the doser after a number of hours of non-use will do more towards reducing admixing of different types of coffee and of stale retained coffee grinds, then will frequent disassembling and cleaning of grinder burrs and grind chambers, in my view, and has almost zero chance of doing harm to the grinder.

This topic has been discussed ad nauseum before and some searching through the grinder forum will yield a number of prior threads.

ken

I wouldn't be so worried about staleness... what about wasting all that coffee? That is quite a bit of retention.

SOP after grinder cleaning is to run a couple of shots into the bin to fill the nooks and crannies.
Once the nooks and crannies are filled, in = out.

Not buying into that theory as it would depend on grinding chamber design, etc.

It's not a theory. Grind chambers are round. What varies are the exit chute and vanes.

Clean a grinder. Grind a light or dark roast for a while. Switch to the opposite. After a couple of doses, there is little of the prior coffee in the shot. Grind the opposite for while. Now disassemble the grinder. You'll find the first coffee packed into the voids with a layer of the alternate atop it.

It's not possible for a grinder to continually retain part of what is ground, save being a micro black hole.

Ian, why are you talking about vanes, which I assume you mean doser vanes, when this conversation is regarding grinder design, not doser design/function?

Doesn't matter if all chambers are round, because design of the chamber can play a part.

The design and speed of the sweepers have alot to do with retention based on what I've seen. I use a NS MDX daily and it never has any retention in the entire grinding chamber, only what builds up in the throat going to the doser which is easily swept out daily.

So the sweep is a vane in the doser and not a vane in the grind chamber
The function is the same : move the coffee out of the chamber / doser .

BeastinBarista wrote:Don't waste your time trying to dispute what I have to say on this forum. Have read lots of your posts and really think you know very little. Especially your "theories" on the infamous KA Pro Line grinder. I've managed to massage excellent grind quality out of my Pro Line with a bit of tinkering when you and others claimed it was nearly impossible. You/others just don't have a clue as to what you're doing.

Nice to know.