I bought a used '02 Mazzer SJ a few weeks back and I know I have to replace the burrs (that will be a fun night - never did that before) but would that be the reason why my ground espresso is clumping? I roast my own beans (dry processed) and let them rest 5 days before use so the beans are fresh. If it's just a dull blade issue, then I'll chill about it until I replace the burrs.
Thanks for all your help:)

Cheri,

Are you dosing as it grinds? I ask because this is what most people do to break up the clumps. If not, then yes, you will see clumps if only dosing once you've ground enough for one shot, or at least I did on my Mazzer (purchased brand new, so no chance of dull blades).

And, even if you are "twacking" while grinding to dose into the PF, some coffee will still have some clumps. BUT, they're not big dense coffee rocks. They'll collapse when you tamp, so you should be fine.

As for changing the burrs, its a piece of cake. Remove the adjustment collar, and lift out the top burr carrier. Each burr is held on with three screws. Unscrew the old ones, screw in the new ones. Put the top carrier(with new burr now installed) in the grinder, and thread the adjustment collar back in. Don't try and force the collar in, you could cross thread it, and THAT will not be an easy fix. But, don't worry, using plain ol' common sense, you'll be fine.

JmanEspresso wrote:Don't try and force the collar in, you could cross thread it, and THAT will not be an easy fix. But, don't worry, using plain ol' common sense, you'll be fine.

If common sense fails, see Mazzer reassembly problem after burr replacement for hints.

I would add that when I have the collar off I will run a tooth pick along the threads to clean them out. The threads are deep and tight so adjusting gets stiff as fines/oils build up on the bottom of the thread grooves. I then keep the threads dry with no lube.

I have found the speed at which you run the doser "twacking" will effect the clumping and of course the direction of distribution ..so try and play with the speed ... single dose/grind does appear to work best for getting fluffy , non clumpy grinds.
I just put a set of new burrs in my SJ last night .. piece of cake ..just remember ..reverse thread on upper collar and as said earlier clean the threads, make sure to have a newer (proper size) screw driver on hand with a nice square edge, don't try using an old beat up one.. downward pressure to break the screws lose and your good to go (fyi..both burrs are the same).. one thing to pay attention to if your using the set screw for the hopper... ..position the upper burr housing/support so hopper shut off is not facing forward, sort of ugly + brush/vac everything out real good and Enjoy!

I've found a bunch of wonderful informative threads to cover this grinder top to bottom.

When rethreading the burr carrier on a Mazzer, I like to use a toothbrush to clean the threads. Following that with a very thin layer of food grade lubricant like this will make grind adjustments smoother.

Minor "clumping" - at least in my case, also seems to be affected somewhat by the relative humidity.

I'm using a SJ, which seemed almost new when I picked it up used.

I have never seen any clumps which didn't immediately resolve easily. You just barely touch them with something, and they fall apart.

Short version - if tamping readily and clearly breaks up any clumps, I don't see why there is an issue.

Just 'cause, have a set of Chinese takeout chopsticks on hand (well, *always* have a set on hand, 'cause they have a million and one uses) to stop the bottom carrier rotating when you unscrew the bottom burr screws. It doesn't damage the carrier or the chute, and you can pitch the chopstick if it gets dinged.

And it makes a great excuse to get some Dim Sum!

And yeah, I double the advice to have the proper sized screwdriver in good shape. The blade should fit snugly in the screw-head. It should be pretty close to the same size as the slot, both in width and length.

Thanks to everybody for your thoughts. I feel brave now about replacing the burrs.
The clumps were kinda boulder sized - a little on the large size, I thought. uscfroadie, I do dose as I grind.
But here's the strange thing - this morning there were no clumps. Maybe the Mazzer heard I was talking about it and decided to step up. I was mostly curious about the clumps.