Mazzer Mini Burrs (Old and New)
Signs of Wear and Tear, Original Machining Marks, or a Small Amount of Damage from a Foreign Object?
(Al Ruscelli -- March 2007)
Photographs Copyright Al Ruscelli Photography
Photos Taken with a Canon 1D Mark II and Canon EF 100mm f2.8 Macro Lens
I recently purchased a second-hand Mazzer Mini coffee grinder and pulled the upper burrs out to clean the burr set and inspect the burrs for damage. The photos below were taken after blowing most of the accumulated coffee grinds/residue from the burrs using an air compressor. A thorough cleaning had not been done, so there was still a bit of compacted coffee residue visible (especially when viewed via a macro lens).
Although these burrs seem mostly fine, when one looks closely (as the macro lens allows) a small amount of damage or imperfections can be seen on some of the blades.
With my limited knowledge, I initially couldn't tell if the imperfections seen on the burr blades are caused by wear and tear, or might actually be original machining marks/imperfections, or minor blade damage -- or a bit of all three. Initial feedback from the forum members at www.coffeegeek.com indicated that it was very likely some foreign object got into the burrs at some point (maybe a tiny piece of metal or the like) and caused a bit of damage to a few of the blades. The grinder produces and awfully fine grind though, so it doesn't seem as if it is affected small bit of blade damage or imperfections.
In any case, the macro view provides an interesting look at the coffee grinder burrs.
Photos of a new set of burrs will be posted for comparison purposes in the near future.
Click on Any Image to View a Larger Version
Compacted Coffee Even after a Partial Cleaning
A couple of interesting close-up shots of the machining marks and coffee grounds accumulation/compacting around one of the screw holes
Preparing to Clean the Original Burrs with Urnex Grindz
Want to see old burrs get a really nice shine? Try some Urnex Grindz on them. All of the photos above on this page are before the Grindz cleaning. The ones below are after using Grindz, then following up with another air compressor cleaning and "brushing" with an old Sonicare toothbrush head.
I cleaned up the burrs on my Mazzer Mini using an air compressor blower attachment, a spare toothbrush tip for a Sonicare toothbrush, then Grindz, then one more go-round with the air compressor blower.
Original Burrs Cleaned with Grindz (by Running Some Grindz through the Grinder)
Miscellaneous Views of the "Teeth"
Between the burrs looks like a rather unpleasant place to visit, Mr. Bean.
The same image repeated three times but showing (in the second two) what I am interpreting as the way the burr blades work to produce the final ground coffee.
Measuring and Viewing the
Distance between the Burrs and a Closer Look at the Outer Burr Edges
(My Unscientific Method for Measuring)
Interesting Side Notes on Adjusting the Mazzer Mini Burrs:
Given: One adjustment collar, 10 major divisions on the collar (0 through 9), 100 total hash marks (or tick marks) on the collar, and assuming a 1.5mm thread pitch (AND assuming the Mazzer Mini and NOT some other grinder).
One full turn of the collar results in a 1.5mm rise or fall of the burrs.
On major division adjustment of the collar results in a .15mm rise or fall of the burrs.
One hash mark adjustment of the collar results in a .015mm rise or fall of the burrs.
Interesting stuff to know.
View from Outside the Burrs
With About .5mm Separating the Burrs
From the "zero" point, this .5mm separation would be about a three-number (or 30 hash mark) adjustment of the adjustment collar.
View from Inside the Burrs
These show the same separation distance as the views above (about .5mm separating the burrs)
Views Emphasizing the Angle of the Larger Grinding Blades Away From the Outer Edge "Flat" Areas (Shiny, Outermost Edge Where Fine Grinding Takes Place)
New Burrs for the Grinder
(How Ugly Can They Get -- For Brand New, That Is?)
Here are photos of a brand new set of burrs for the Mazzer Mini. I have to admit, I was shocked by how gritty and ugly they looked right out of the package. And the machining work on them looks (to my eyes) quite sloppy. I can't help but wonder how much of a conscientious effort is put into producing replacement blades compared to originals. These look quite sloppy when viewed through the macro lens. Sharp, but full of grit, metal shavings, and what even appears to be some rust. I'll clean them up and see how they look after putting them through the same process as the old burrs. (But, perhaps all burrs start out this way and get cleaner by virtue of all the coffee beans that pass through the burrs, I dunno.)
Here's where things start to get ugly (with the really close-up look at the brand new burr set, fresh out of the package).
It's obvious that new burrs need to be cleaned thoroughly before use with coffee you're actually going to drink. I'd recommend it, in any case (although I got no "clean before using" warning with the new burrs I received -- either from the seller or the manufacturer).
Burrs After a Partial Cleaning
(With Air Compressor and Brush Only)
At this point (photos below), the new burrs have been cleaned with the air compressor and toothbrush method. Most of the grit has gone away, but the ugly machining is still apparent. Perhaps use of a poorer grade metal was involved? Could be. They don't look much different when viewed from the far away (like the two photos immediately below), but as you look more closely (thanks to the macro lens), you can see a drastic difference in the overall cleanliness of the burrs. (Still fairly ugly, though.)
Next Up: The New Burrs Cleaned with Grindz to See if We Can Get More Improvement...
...And YES We Do!
New Images: Cleaning with Grindz did was great for removing and true external debris, but of course did nothing for the worst of the machining marks and metal spurs. Those spurs likely will not affect coffee grinding at all -- my guess based on limited knowledge, since the find grinding takes place on the outer part of the burrs where there is NO bad machining. (Thanks, Ken, at www.home-barista.com for enlightening me with some of the illustrations on his site.) But still, for those interested, I present cropped and close-up images of those machining marks (as a point of curiosity).
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