Eureka Mignon Specialita calibration issue?

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

#1: Post by Aegon_85 »

Hi, I have just upgraded from Rocky to EM Specialita.

I have owned it for 2 weeks now and been very happy. Upon receipt I checked if the zero point of the grinder matches the actual zero mark on the knob (with running machine I was rotating to 0 until I heard burrs slightly touching). From then on I starting making minor adjustments for my espresso. I have been grinding around point 2 and I use my specialita only for espresso. All changes made were 0,5, max.1 point.

Yesterday, however, I was changing to different beans and wanted to start again from point zero and then move to coarser setting. Turning the knob with running machine until hearing the burrs touch, I realized, that my zero point has moved now and instead of 0 on the knob it is on mark 2 of my knob. After playing around with it a bit longer, opening the the grinder, checking the burrs, cleaning it, I tested again and this time my zero point moved again to mark 3 on the knob and a decent shot was about 5. I screwed out the knob, put it back, no effect. Cannot return to point 0 with the burrs.

Now, I don't know what I am doing wrong, I am afraid I messed up with something and every time I want to calibrate the grinder, burrs touch at a higher value, which shouldn't happen in my opinion.

Could you please advise? Does anybody have a similar experience?


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#2: Post by barNone »

You can't use the Mignon's dial for 'absolute' values. My experience has been the same, turn the dial one way, then the other, end up with a different grind fineness for the same number on the dial than before I started the adjustments.

It's just the way this design is. The dial is attached to a long screw that pulls the motor up and down to control the lower burr height. When it's turned one way then the other, it untensions the screw from the nut for say 10-15 degrees where the lower burr doesn't actually move until the screw's threads start applying force on the nut the other way, i.e. hysteresis. All this to say there's too much play and the result is no fixed zero reading. IIRC, one of the Ceado grinders has a movable number plate on the adjustment collar to recenter the dial to read 0, probably for the same reason.

Aegon_85 (original poster)

#3: Post by Aegon_85 (original poster) » replying to barNone »

Thanks for the explanation. I have contacted OEM with the same question and got the same answer as yours. BTW amazing customer service, reply came within an hour or two, even to my follow-up questions.

I guess I haven't fully realized the difference between the step-by-step machine like Rocky I used to own and a stepless design of Eureka. Just happy it is not broken, it would have been a massive blow to my Christmas plans :)

Thanks again.