Found a cheap ($150) super jolly on craigslist ~2 years ago to accompany my 5 year old brewtus 2. Years of heavy cafe use (the cafe under the burke museum). Expected to replace burrs but when I got home and after cleaning it out I didn't bother since performance was such a significant improvement compared to the 4 year old Nuova Simonelli Grinta I'd been using before. Ground faster and finer and I assume more consistently since pulls were better. Most noticeably it was quieter and doser made for considerable mess reduction.

I found the best setting was about 2 notches above the point where the burrs collide with only 1-2 notch adjustments since then.

I've been struggling to improve my cup for the past few years and I finally got round to ordering new burrs last week, went for the duraniums and they arrived last night. New burrs felt sharp, was easy to catch ones fingertips on them. Old burrs looked the same but you'd really need to work to cut yourself with them.

I first set the grind where it had previously lived, 2 notches back from touching. No coffee fed through. After first assuming that I'd put them in wrong I checked the old burrs (yes, top and bottom really are the same.) I pulled the hopper off and slowly dialed back the grind until beans started to flow through. That was 2.5 full NUMBERS back from the zero point and coffee still felt finer and fluffier than I'm used to. I dialed it back a little more until it felt right to me.

First shot and I'm surprised by the pornographic crema spurtage. This is half way through a 6 day old bag of vivace dolce, only difference was the burrs and I can basically fill a cup with crema with slight blonding at the end. I previously could taste a little sediment or particulate in my shots and that is gone now and coffee tastes very fresh. Dialed the grind finer and was able to replicate that dark purple crema of a vivace ristretto (though not quite their ensemble of flavors). I'm very surprised the burrs made such a difference.

1) These new burrs make a sufficiently fine grind with much more room between the burrs.
2) Dull worn out burrs hurt the quality of the espresso.
3) Fast: grind for a shot takes about 3 seconds. Too fast?

I can't speak of the relative merit of duraniums but no regrets here. You've read it before, here it is again: replace those worn burrs!

Thanks Jim.

I visually compared the old/new burrs right before installing. The new ones have the same 2 groove depths as the old one, but then the new ones also have some short and much deeper groves.

Coffee is now very fluffy. I'm still surprised how much better the pulls are. I'm still unable to replicate the precise flavor I'm after, but am certainly closer.

Could you provide more info on the burrs ? Part #, where ordered from ? Rebuilding an SJ and would be interested in installing these burrs.