Do grinder settings change while breaking in?

Grinders are one of the keys to exceptional espresso. Discuss them here.

#1: Post by scareyourpasenger »

I am a new owner of a Cimbali Max Hybrid. It has been great so far but I noticed my pours were taking less time and I was getting more gushers. The grind seemed to feel coarser so I started adjusting it finer to see if would help. I have adjusted it down from 2.25 to around 1 which usually makes a very big difference in taste. It is still flowing quite fast at around 15 seconds when pulling a shot and I don't think Channeling is the issue because the bottomless shows what looks to be a decent pour but way to fast.

I don't know if this helps but the grinder sounds a bit different with less mechanical whine now vs when I got it new. At this point I think I have about 5lbs through it or just a bit less.

Is this normal? Should I pull the machine apart to inspect the burrs?


#2: Post by Mark08859 »

Grinder settings may have to be changed for a number of reasons. Breaking in burrs can certainly be one of them. Age of beans or humidity can be other factors. When was the last time you cleaned the grinder?

scareyourpasenger (original poster)

#3: Post by scareyourpasenger (original poster) »

I have cleaned the doser out but that is about it. I have had it for 3 weeks now so I didn't think I needed to pull it apart and do a full clean just yet.

All the beans are fresh ranging from roasted 2-7 days ago.

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#4: Post by Jeff »

I noticed my spankin' new K10 seemed to require a progressively tighter setting to achieve the same grind over the first couple pounds of coffee. I had never given much credence to the "you need to season your burrs" statements, especially as I find it hard to believe that burrs that are supposed to be good for thousands of pounds of coffee "wear" in any measurable way in the first five or ten pounds, but it sure seemed to be my experience. Maybe there is something to running a couple pounds of "spare" beans through a new grinder?

On the other hand, maybe it is just the normal changes that occur when beans age or the weather changes?

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#5: Post by HB »

Before testing, I run two pounds of stale coffee through small grinders (e.g., Baratza Vario) and five pounds through big grinders (e.g., Compak K10). This seems to eliminate meandering grind settings that otherwise occur the first week or so. New grinder with poorly machined burrs suggests that sloppy finishing is the root cause.

Previous discussions of this topic:
Jeremy, do let us know if you notice an improvement in grind setting next week, if only to add to the anecdotal evidence asserting the "break in period" is real.
Dan Kehn

scareyourpasenger (original poster)

#6: Post by scareyourpasenger (original poster) »

Thanks for the links. I hope this is just a break-in thing otherwise I will have a heck of a time dialing it in.

scareyourpasenger (original poster)

#7: Post by scareyourpasenger (original poster) »

Quick update. I ran the grinder to the zero mark as an extreme change to see what it would do. Grind is back in the ballpark again and the shot I pulled lasted 27 seconds. I am tempted to locate some cheap beans to make sure it doesn't need further break in. It does bother me that numbers don't come close to representing the true zero point.

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#8: Post by HB »

On a related note, Breaking in Robur Burrs - A Solution? proposes an approach for big grinders that doesn't require stale coffee. Thanks to Twitter user David Walsh for the link.
Dan Kehn


#9: Post by specialpants »

Interesting read about the clay balls. I don't think this is something I'd try on an expensive grinder :shock:

Instead of using clay balls, or wasting kilos of roasted beans to season the grinder - perhaps another option is to use green beans? I'm guessing it has a hardness that's somewhere between roasted beans and clay balls. Or not just in case the grinder gets damaged...

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#10: Post by shadowfax »

I would not use green coffee beans. They're quite hard-MUCH harder than roasted beans-and may cause your grinder to lock up. You might, however, be able to speed up break in with some super-light roasted beans. Those will be harder than Full City(+) roasted beans and should wear your burrs in a bit faster (so you'll need less).
Nicholas Lundgaard