Cleaning a Mazzer Mini

[KarlSchneider]

I recently asked an espresso machine sales / repair firm

"I have had my Mazzer Mini for 3 years. I grind less than a pound a week. I assume I do not need to worry about new burrs yet. is there a cleaning routine I should follow?"

<Reply>

"As for the Mazzer, I would suggest leaving a good thing alone. One customer just tried to clean his Mazzer grinding chamber, and he is having the most difficult time putting it together.... Grinders in general do not need any maintenance unless you are in a coffee shop setting."

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I welcome suggestions from readers of this forum if they recommend a routine. I have read about using expensive cleaning materials from Urnex and other things. I suspect I have ground no more than 150 lbs of coffee in my Mazzer so far which is well below their burr replacement suggestion (I think it is 350#) but that may apply to cafes and not home use.

I am interested in general maintenance as well as burr replacement.

Thanks for your help.

[HB]

The thread Urnex Grindz Espresso Grinder Cleaner offers opinions on the subject, including the usage of rice instead of Grindz. I've heard the same advice as your repair firm's, probably because they worry the owner will cross-thread the burr carrier. The rice-once-a-month routine satisfies most of my neatnik urges; I'll remove the burr carrier for inspection once or twice a year. At least for the Mazzer, the difference between one week and six months of trapped buildup isn't readily apparent - what the rice (or Grindz) doesn't get is redeposited post-haste.

According to the owner's manual, the Mini's burrs are good for 300 kilograms of coffee. When the day comes to change them, it's a 10 minute operation. The tricky part is the upper fixed burr assembly "floats" on three stiff springs. These springs push the upper aluminum cast assembly against the chromed steel collar. That tension is good for keeping the setting firmly against the top of the threads (no slop) and prevents the collar from moving, but means you have to push against three springs to rethread the collar. Some owner's cross-thread, especially if they have trouble finding the first thread's engagement point or forget that it is reverse-threaded (counter-clockwise is tighter).

Hint: If you mark the disengagement point on the collar with a felt-tip pen, it will be easier to rethread later (i.e., to rethread, set the collar gently on top of the threaded chamber, turn it past the point of engagement until it "drops" into the first thread, then reverse to engage the threads). Again the tricky part is holding the floating burr assembly down far enough to allow you to engage the threads while they are not under tension (you could drop a tamper into the throat of the grinder and ask a second person to push down firmly).

My grinder hasn't been opened up in awhile. Tomorrow I'll take some before/after pictures after a Grindz treatment, then you can decide for yourself it it's worth the trouble. I will also snap some pictures of the disassembly / reassembly.

[KarlSchneider]

Dan,

Thank you for the link, the description and the encouragement. I should have done a search but did not think to do that.

I may get the courage to take the burrs apart. As you undoubtedly have gleaned i am far more comfortable on the subtleties of the aesthetic side of espresso and machines that I am on the complexities of the technology side.

[HB]

You may want to avert your eyes, this isn't pretty. I've been slacking off lately on my grinder maintenance, as you can see from the buildup on the upper burrs:


Upper burrs before cleaning


Lower burrs before cleaning

The grinds adhered to the upper burr's sides, forming a rounded corner of old coffee. The lower burrs fared better, except for the three agitator / ejector vanes, which accumulated a thick smudge of grinds. Bleech. Let's see what Urnex Grindz can make of this mess:


Upper burrs after cleaning with Grindz


Lower burrs after cleaning with Grindz

Not surprisingly, what was caked on stayed put. The other surfaces are shiny and lighter without any evidence of oil buildup; if Grindz is to be effective, looks like you need to use it frequently enough that coffee grinds don't get a foothold. Now that we've seen the quick-and-easy approach, let's review the old-fashioned way, starting with how to remove the burrs.

• Empty the hopper, run the grinder until the chamber is empty. Set the hopper aside.
• Important: Unplug the grinder. Don't just turn it off at the switch, unplug it.
• Remove the safety limiter Phillips screw from the chrome-plated collar. Its removal allows the collar to spin freely.
• Turn the collar clockwise to remove (it's reverse threaded). Carefully mark the collar at the point the threads disengage with a felt-tip pen for later reference.
• Clean the burrs with the implements of your choice. I use a small stiff bristle brush, vacuum cleaner, toothpicks, chopsticks, and for the really teenie cracks, a sewing needle. Apply no oils or introduce water into the grinding chamber, and obviously no chemicals of any sort.

As I mentioned earlier, screwing the collar back on can prove challenging because you must push down the upper burr carrier against three tension springs while engaging the threads. You can do it yourself by pushing the aluminum carrier down with the flat of your hand while rotating the collar with your other hand, but I recommend getting a helper:

• Place the upper burr carrier and collar in position. The mark noting the disengagement point should be an inch or so prior to the start of the thread (i.e., the dot on the collar should be to the right of the engagement point).
• Place a tamper into the throat of the grinder. Ask your helper to push down. It won't require a lot of force, compressing the springs a few millimeters is enough.
• Rotate the collar clockwise (remember, it's reverse threaded, this is in the looser direction). The thread of the collar should nicely drop into the thread of the lower assembly. Continue turning just a little further, then reverse to engage the first thread.
• Remember to put back the safety limiter screw.

Note: The threads engage easily. If you feel resistance, rotate the collar clockwise to remove and try again. Take your time, cross-threading the collar would be a costly mistake!


Lower burr after Grindz and hand cleaning

[Woofy]

In addition to the tools mentioned, I have found that a good set of stainless steel dental instruments (under $10 a set at http://www.duluthtradingcompany.com) are amazingly useful for this task. I have Duluth's set with the case and tweezers. It's come in handy for everything from working on my motorcycle to refinishing fine furniture and is a real frustration saver.

[HB]

Looking at my "before" photos, it's really inexcusable.

If you've fallen behind on your grinder cleaning regime like I did, here's another motivation to mark the calendar each month: I noticed that since cleaning the grinder's chamber, my extractions are more even. The vanes not only eject the grinds out the chute, but agitate / remix the grinds beforehand for even less clumping; I can see an extra "fluffiness" in the grind too that was lacking lately.

The owner's manual (of course) doesn't recommend how often the chamber should be cleaned. How often does a good cafe do it? Weekly?

[KarlSchneider]

Hi Dan,

I finally had time and the courage to tackle my Mazzer. Thanks to your excellent descriptions and photos I managed the whole process by myself. The trick seemed to be to remember that the threads are reversed. It took me a bit to get back down to proper fineness of grind. I may count rotations next time while unscrewing. My top ring disengaged with #7 opposite the notch facing the doser.

Again thanks for the help and support.

[IMAWriter]

You may want to avert your eyes, this isn't pretty. I've been slacking off lately on my grinder maintenance, as you can see from the buildup on the upper burrs:

Carefully mark the collar at the point the threads disengage with a felt-tip pen for later reference.

Just wondering why it's necessary to "carefully mark the collar"....I've got a mark on the collar where my burrs touch...i've removed the upper, cleaned out the lower section and using your push down method, replaced the upper section, being careful to avoid cross threading....everytime, I hit my burr touch mark exactly...not even one notch off...seems like if threading is performed correctly, a mark for thread disengagement would be unnecessary...but if I'm wrong.....

[HB]

...seems like if threading is performed correctly, a mark for thread disengagement would be unnecessary...

Agreed, it's only a hint. I offered (overly)cautious guidelines because cross-threading the collar would be a costly mistake.

[KarlSchneider]

Just wondering why it's necessary to "carefully mark the collar"
...seems like if threading is performed correctly, a mark for thread disengagement would be unnecessary...but if I'm wrong.....

Since I started this thread allow me to add that Dan is keenly (kehnly?) aware that we who read these posts have a wide range of skills. Mine are clearly not on the technical / machine side of the spectrum. Accordingly I welcome all these simple (simplistic to many) comments. After two years of neglect my grinder is now clean thanks to Dan's help.

[IMAWriter]

Since I started this thread allow me to add that Dan is keenly (kehnly?) aware that we who read these posts have a wide range of skills. Mine are clearly not on the technical / machine side of the spectrum. Accordingly I welcome all these simple (simplistic to many) comments. After two years of neglect my grinder is now clean thanks to Dan's help.

Oh, sure...suck up to the "Kehn-meister!" ;>D
kidding aside, Karl....there is probably no one on the HB/CG/alt.coffee scene that Dan hasn't helped, in one way or the other....yours truly included (many times!)
This wonderful site is his crowning acheivement...whoa, talk about sucking up!

[Bon]

Thanks for that, I just cleaned my 3 week old mazzer mini out then using your guide... too easy!

[iginfect]

Applying grease to the threads really helped getting it back in. It looked like there was some 4 year old lithium "Campy" style grease in there; I used some old Phil Wood synthetic grease, don't know if its still made. Using the 58 mm tamper and grease makes a helper superfluous. I had to take it apart as I broke a drill bit trying to make 2 holes to fit a cover over the open space left when I mounted the funnel to replace the doser. The bit got inside and blocked the burrs. What a mess of old grounds in there.

Marvin

[DaveC]

Applying grease to the threads really helped getting it back in. It looked like there was some 4 year old lithium "Campy" style grease in there; I used some old Phil Wood synthetic grease, don't know if its still made. Using the 58 mm tamper and grease makes a helper superfluous. I had to take it apart as I broke a drill bit trying to make 2 holes to fit a cover over the open space left when I mounted the funnel to replace the doser. The bit got inside and blocked the burrs. What a mess of old grounds in there.

Marvin

My wife always has plenty of high quality lip salve hanging around.....totally food safe, flavourless and makes a great lubricant for all sorts of coffee related parts; Threads on a Mazzer, top roller and pins on a spring lever, or rings in OPVs, valves, breakers.....funny thing though, I am finding the lip salve much harder to find nowadays.

With the Mazzer Mini E, and I can't see why it wouldn't happen on a Mazzer Mini (which I have also owned). You can get a buildup in the rebate of the upper burr carrier. This can give a false feeling of the "point at which the burrs touch". It can also make the grinder make a slightly different noise (quite subtle a sort of higher pitched rub sound). It becomes quite difficult to adjust finer, with it either running or empty and stationary.

I normally have at least 4 different types of roasted in the cupboard and all needing different grind settings. One a Dominican Barahona requires a much finer grind. I find this seems to make the problem worse, if you are making large adjustments of grind (3 or 4 notches) a lot. When this buildup is cleared (cocktail stick), everything goes back to normal. I would have thought the "arms" which throw the ground coffee out, would scrape it clear, but they dont! I have taken some pictures and when I get the time will be inserting a small article on my website, but thought it was worth posting here after reading the thread.

I clean my grinder out about once every 2 weeks or whenever the above happens, basically just a quick brush out and a vacuum, never felt the need to wash the burrs. My main tool of choice is a wooden cocktail stick (although I have used my dental tools as well).

[Psyd]

The owner's manual (of course) doesn't recommend how often the chamber should be cleaned. How often does a good cafe do it? Weekly?

I make sure to get my nose into the game. If my bean canister smells a bit like old beans, I wash it. When the grinder doesn't smell like fresh ground coffee anymore, I clean it. Humans have forgotten that the olfactory sense is a tool just like the eyes and ears. If it smells bad, it probably is, and if it smells edible, it probably is. Of course, there are notable exceptions, but if smell weren't a really good indication of stuff, perfumeries and manufacturers of of deodorants wouldn't spend so much time on boats and planes....
BTW, how do you like the Alex, DaveC? I have the pro two group that I'm getting over, the novelty of using a giant Caterpillar dump truck to haul small loads around is wearing off, and I'm eventually gonna want my kitchen back, and I was thinking that the Alex was the answer to having a replacement that would live on the countertop, and remain on 24-7. Wouldja recommend it?

[cannonfodder]

My wife always has plenty of high quality lip salve hanging around.....totally food safe, flavourless and makes a great lubricant for all sorts of coffee related parts; Threads on a Mazzer...

I would not use ANY kind of lubricant in a grinder especially in the burr carrier threads. Lubricant attracts dust, dirt, grim and other nastiness that will just gum up the fine threads.

[Everman]

I clean my mazzer about every six months or so. I only use about 1/2 lb a week typically unless I'm really working a new blend. I've always made sure to note where to begin threading it and it's never been a problem. It always maintains the exact same setting locations as prior to disassembly which is pretty amazing.

[HB]

BTW, how do you like the Alex, DaveC? I have the pro two group that I'm getting over, the novelty of using a giant Caterpillar dump truck to haul small loads around is wearing off, and I'm eventually gonna want my kitchen back, and I was thinking that the Alex was the answer to having a replacement that would live on the countertop, and remain on 24-7. Wouldja recommend it?

Follow on discussion merged with prior thread on the Alex.

[DaveC]

I would not use ANY kind of lubricant in a grinder especially in the burr carrier threads. Lubricant attracts dust, dirt, grim and other nastiness that will just gum up the fine threads.

I have not seen that view expressed before, I guess it's worth thinking about. As is why the manufacturer (Mazzer), must have some reason for putting lubrication on the threads, also the manufacturer of my Rossi RR45 grinder?

I have no idea what the manufacturers thinking was, but have always thought it best to lubricate those threads because thats how they came from the factory and the adjustment ring seems to turn a little easier (possibly different if they were brass threads)..

[cannonfodder]

Part of the problem is that people have a bad tendency to over lubricate. I would not use more than a pencil eraser sized drop of food grade lubricant for the entire machine. To properly lubricate precision machinery, apply a very small amount and then wipe it until it appears to be dry. Now you have just enough lubricant.