How important is running the grinder while adjusting?

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

Postby mitch236 » Mar 28, 2012, 9:16 am

This may have been covered before so please excuse me if I ask a question that's been answered. I wonder if I would be damaging my burrs if I make small adjustments (usually one notch or less on the mazzer collar) finer while not running the grinder.

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Postby aecletec » Mar 28, 2012, 9:20 am

I don't know about damaging burrs, but I have noticed that my burrs would jam on the coffee if the grinder was not running when approximating the surfaces.


Postby d2addict » Mar 28, 2012, 9:44 am

You'd better not do that, But if you are just going a bit finer it wouldn't be a problem.


Postby darilon » Mar 28, 2012, 9:59 am

Going coarser is probably ok, but not going finer. As previous poster said, you could jam the beans and stall the grinder.


Postby mitch236 » Mar 28, 2012, 10:47 am

I guess I was really asking about the possibility of damaging the burrs, not stalling the grinder.

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Postby HB » Mar 28, 2012, 11:00 am

Short answer: I don't recommend adjusting finer if there are coffee grounds in the grind chamber and the motor isn't running. Either run the motor if adjusting finer, or empty the grind chamber beforehand. There's no need to run the motor or empty the grind chamber if adjusting coarser since the burrs are moving away from each other.

Long answer: The Mazzers have large startup capacitors, so they'll tolerate half to full notch adjustments finer without complaint. But some grinders I've used stalled on occasion when I adjusted a tad finer (e.g., the Compak K10, Macap M4, Baratza Vario). Obviously that's not good for the motor since the windings may overheat, but the burrs shouldn't be affected. Some vendors have posted rather dire warnings about the practice. I've read reports of the burrs becoming coated with coffee tar (?) as a consequence of ignoring this advice, necessitating removal/cleaning of the burrs.
Dan Kehn

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Postby Peppersass » Mar 28, 2012, 11:41 pm

I've trained myself to never touch a burr grinder adjustment unless the grinder is running, regardless of the direction in which I'm adjusting. I run the motor even if the burr chamber is completely empty, which is always the case between shots with my K10 because I single dose and pulse/sweep thoroughly. My philosophy is that you can't go wrong if you always run the motor while adjusting.

I presume you're asking the question because you have that mini-hopper/column and don't want to waste coffee while adjusting. Don't see a way around that, except adjust fast!

I know the Robur is the be-all/end-all of espresso grinders, but sometimes I think you would be happier with the ergonomics of the K10 :mrgreen:.

Ben Z.

Postby Ben Z. » Mar 29, 2012, 12:13 am

Do it all the time. I figure a notch finer is in the "just squishing some ground beans a little" category.

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Postby cafeIKE » Mar 29, 2012, 12:34 am

FWIW, I've adjusted 3 Macaps, conical and planar, finer by 1 click / 2 teeth for more than 6 years with nary a whimper. Ditto several Mazzers, conical and planar, and 1 Cimbali Max Hybrid conical / planar.

It's possible to crush a bean between thumb and forefinger. Coffee is just not that tough.
Would I grab a 1/3hp motor with 2" shaft and try to prevent it from starting? Not bleedin' likely.
A 1.2hp Robur w 3" shaft? Are you nuts?

Any grinder that could jam due to 0.02mm decrease in burr separation would be mighty susceptible to jamming in normal use. Any grinder that does probably has a defect either in motor, starting cap or wiring.

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Team HB

Postby RapidCoffee » Mar 29, 2012, 12:55 am

As usual, the answer is: it depends. When I replaced the standard burrs on my old SJ with the faster, more aggressive Duranium burrs, I experienced several grinder stalls. This was most likely to occur when I adjusted the grind setting finer when the grinder was not running, especially with small (e.g. Yemeni) beans. This would not damage the burrs, but could damage the motor. (Or so I'm told.)

I often make small grind adjustments on my Robur without the motor running, and have not stalled the grinder yet.