Niche Zero: grind size mysteriously got much much finer

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

#1: Post by barNone »

I've had my Niche Zero for 3 months now and everything had been working smoothly and as expected. Then recently over the weekend, I ground the same beans and the extraction completely clogged up my espresso machine. I increased the Niche's grind setting another 6 notches (i.e. ground much coarser in relative terms) to get a similar extraction time as before (say 18g in, 36g out in 27 s roughly), so the problem isn't the espresso machine. I opened up the grinder several times, cleaned, calibration never changed, reassembled, the mysterious +6 offset was still there several coffees later: all these coffees extracted as consistently as before.

When I had the burrs removed, I noticed that the triple sweep arm at the bottom was raised from the grind chamber floor by a business card's thickness, fractions of a millimeter. I could've sworn the sweep arms are supposed to sit flush, but I never paid close attention before and I don't remember for sure. It's like the motor shaft or something near there (bearing assembly?) suddenly shifted up, pushed the sweep arms up, which then moved the lower burr closer to the top burr. I didn't see any grounds or debris in the motor shaft area that would force the sweep arms to sit higher suddenly. The motor shaft seems tight in all directions.

Could someone confirm whether their Niche's sweep arms sit flush on the grind chamber floor and makes contact? It makes sense that they would to achieve little to no retention. If this is true, then I am not sure what happened.

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jinrowang

#2: Post by jinrowang »

Just checked mine. It's intact with bottom.

thebookfreak58

#3: Post by thebookfreak58 »

This is interesting, I have the opposite happen to me.

I have one of the original Made in UK indegogo Niche Models.

I was usually grinding for espresso in the 15-18 mark, very consistent, never changed over the time I've had it. But all of a sudden I had the opposite issue, my grinds became very coarse. Now I grind at the 2-3 mark. Haven't touched the calibration (since I did it out of the box), nor have I ever opened up the grinder...

LObin

#4: Post by LObin » replying to thebookfreak58 »

What you're describing is different I believe. Quite a common thing with the NZ. You probably simply need to clean your Niche thoroughly and recalibrate. You'll likely be back close to your initial settings although with burrs seasoning, it's normal to expect some changes towards finer grind settings.
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jinrowang

#5: Post by jinrowang »

Same here, 18-20 and it went down to 8-10.

thebookfreak58

#6: Post by thebookfreak58 »

Thanks! Just gave it a deep clean and settings are back to normal. Was pretty gross in there!

GW2K

#7: Post by GW2K »

My grind setting have changed twice only after deep cleaning. Started out of the box at setting 18 for 17g ~> 34g out in 28 seconds

1st cleaning after 1 month caused my setting to increase to 21 to keep same output and time.

2nd cleaning i'm now at 25.

I'm puzzled, but keep trying to figure out why.

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mtbizzle

#8: Post by mtbizzle »

Good demonstration of why people hesitate to treat grind #s as universally applicable... My espresso, before and after clean/calibrate, is always less than 10 on NZ

jwCrema
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#9: Post by jwCrema »

I think grind numbers will be consistent across NZ machines when the roast and bean are consistent.

I have been surprised at the need to tweak the grind for the same country of origin and same roast style from two different roasters. And "need" is relative - always reaching for the perfect cup.

GW2K

#10: Post by GW2K »

GW2K wrote:My grind setting have changed twice only after deep cleaning. Started out of the box at setting 18 for 17g ~> 34g out in 28 seconds

1st cleaning after 1 month caused my setting to increase to 21 to keep same output and time.

2nd cleaning i'm now at 25.

I'm puzzled, but keep trying to figure out why.
After about a week of the sudden grind size change, things returned back to normal. Having the only way grinds could get so fine without me physically adjusting the settings is that after my cleaning, the pieces settled back into place.