Hello,

As mentioned in the subj, my Fuji produces a lot of fines/dust towards the end of the grind - last 1-2 grams of beans.

In container it's nice, consistent and beautifully grinded beans, but there is those fines at the top. They are easy to remove, however, it's a shame to loose 1-2 grams (out of 15-20 grinded).
Problems with the alignment (factory one)? Or because it's relatively new grinder and it should get better with time?

Im using it for manual brew.

i notice the same behavior. it doesn't affect my brewing taste nor does it affect drawdown time. have you experienced any bad effects of leaving them there?

I guess it depends on how you look at it. What I do now, is to remove those fins to the side, start pour and add them back to the brew at around 1min. So total brew time/pour is around 3min.
If I don't remove/add later, my downpour is a lot slower. Taste is still nice, but just tiny bitterness and cup is not as clean in taste.

I have a new one one I'm testing, and I've noticed the same behavior. I'm not sure if the fines are produced at the end of grinding, or if they just cling to the plastic jug and end up at the top of the ground coffee. I think It's a superlative brew grinder, but it has quirks.

There is a shutter at the bean intake, but attached to the grinder, not to the hopper. Maybe it's meant to be closed when the bean level gets low. I've tried to find some mention of it somewhere, no luck so far.

My J-500, an American market import R-440, was like that too. But perhaps less severely since I could mostly get around it by just letting the grind happen and then doing all the retention minimizing tricks into the trash instead of the catch cup. No restarting motors or doing air blasts while the cup is in place.

I just ground 60g of a medium roast coffee. Here are the results. I did not touch the grounds:



Here you can see that the fines at the end barely coat the top of the pile.



I'm guessing those fines amount to less than .5g.

If I had to guess why you see them at the end, it would be due to centrifugal force and the larger heavier grinds falling out first.

are you guys using the 50hz version on 60hz power? this results in the motor spinning at a higher rpm when run on 60hz.

if this is the case, using a converter and running it at 50hz helped with the fines at the end of grinding, but did not eliminate them completely. so perhaps it's due to the higher RPM?

I'm using a 120 to 100V converter. It mentions nothing about frequency. The RPM is lower when running with the converter.

Ditto. Do you know what the deal is with the shutter?

chris_n wrote:are you guys using the 50hz version on 60hz power? this results in the motor spinning at a higher rpm when run on 60hz.

if this is the case, using a converter and running it at 50hz helped with the fines at the end of grinding, but did not eliminate them completely. so perhaps it's due to the higher RPM?

I was wondering that too, but the OP is in Europe (50Hz). Depending on the type of AC motor used, running a 50Hz motor at 60Hz will increase motor speed by 20%, regardless of voltage. (The change in rpm that happens with voltage is due to different reasons.)

However, as Japan has 50Hz and 60Hz regions, there may be different versions of the grinder. I know that the Fuji R-440 is available in 50Hz and 60Hz versions, but I do not know about the R-220.

If the burrs in the Fuji behave like the burrs in the Apex, then increasing RPM might increase fines - this happens in my Apex going from 400rpm to 500rpm.