Couple of months ago I started having extraction problems when grinding with my M3. It started gradually just being difficult, channeling, uneven and not centered extractions, clumping and then this month grind was just so inconsistent that it was almost unusable. I mostly used my Macap M7D since it did not have these problems.

I had all symptoms that people attribute to worn burrs, but at first I could not believe it since by my calculations I started having problems before I put 100lbs through grinder and even if I am very generous and my dog is moonlighting as barrista with M3 I put at most 150lbs through it, so it is well below the 400lbs that burrs are supposed to be able to process.

I saw that EPNW had Cimbali DRM burrs on sale for $20 so I ordered set and replace them last week. I noticed that my old burrs are not sharp when you go with finger over them in both directions. Blind testing confirmed that I can pick 100% old and new burrs by touch alone. What? I blind test tomates in grocery store too!

Anyway, visually you could not see anything on old burrs but on touch there was difference. I did not think it was that big.

But, as soon as I ground first shot with new burrs it came out even, no channeling and for a week I experience no problems I had previously. And it is not that new burrs and grinder are clean, I cleaned old burrs and used them before just to rule that out and it was of no help.

So burrs where worn after only 100 lbs of your regular espresso coffee. Is that possible? Or perhaps I got used burrs (bought M3 new from Versalab) or defective burrs? How do they come up with 400 lbs number anyway? Perhaps burrs are supposed to last about 100 lbs on M3?

Anyway I will be watching how these new burrs perform and will update this post in a year. Burrs are not expensive so I don't mind changing them every 100 lbs, but in case you use M3 and have problems like this and are near 100 lbs through grinder, replace burrs and see whether it helps...

I assume you mean these: http://www.espressoparts.com/MC_32 ?

Your confirmation that these are a good alternative to VL's flat burrs is great news. IIRC, VL sells them for $40!

coffee.me wrote:I assume you mean these: http://www.espressoparts.com/MC_32 ?

Your confirmation that these are a good alternative to VL's flat burrs is great news. IIRC, VL sells them for $40!

Yes, those, they work great. Note that they are on sale for $20, who knows how long it lasts, get them while they are hot

HB wrote:Sure, if there was a stone in them.

Good point, you think I could have ground a stone or stones without ever noticing?

That is good to know, lets see how long these new ones last. I'll post an updated in about year.

FWIW my Robur burrs have about 250 lbs through them and according to reports they should just be getting broken in by now and good for another coupla thou pound or so, without mishap that is. At the rate I'm going that'll take me up to 2025 or so.

so glad you posted the info. i ordered myself some replacements, also. my grinder is over two yrs old , and close to 100 lbs run thru it, too.
one thing i've always wanted to ask other M3 owners is if they grind for espresso and the burrset is sometimes touching when grinding? if not touching, the adjustment for espresso is just about touching the burrset. do you other owners experience the same thing?

I think mine have pretty much lots to go before touching, it is possible yours are worn too. When you replace them see whether it makes difference.