I purchased a used Breville Smart Grinder Pro a few months ago, it was in good shape and my first few months were great. I used it 1x per day and cleaned it monthly. Recently, I noticed a significant amount of fines which are clogging my Chemex and making a brew go from 4-5 minutes to +12 usually starting to stall after my second pour. Beans and technique have not changed and this happened in the middle of a light roast Ethiopian that started at 1 week from roast. I was originally at normal factory settings and a grind size of 41 which worked well. Because of the clogging, I gradually increased the grind size to 59 and even changed the upper burr to #8. While I am getting some larger chunks, there is still a significant amount of fines and brew times are still +10 minutes. I contacted Breville who recommended I clean it (run 1/4 cup of white rice through, brush the burrs, vacuum it from the top and bottom) and while I noticed a slight change, it only reduced my brew time by about a minute. The next step for them is to send the grinder to get fixed for $95 but I was wondering if others might have had a similar issue and there might be a fix out there.

My normal brew: 450g:30g water/beans, bloom for 70 grams, 1st and 2nd pour 190 grams.

The issue is that you're pairing an Ethiopian coffee, which notoriously produce a huge amount of fines, with a grinder that produces a huge amount of fines and uneven particles, with a brewing method that is notorious for clogging with lower-end grinders.

Hope this helps.

Thanks, that makes sense. I wasn't aware that Ethiopian beans had that tendency as everything previously didn't have an issue. I have been recently trying to upgrade my coffee game but realize there is still a lot I don't know. I'll go with a different bean next time and update if it doesn't improve the situation.