Finally got my Geimori GU64 and compared to my DF64 Gen 2, it's definitely fluffier in grinds, thanks to the better anti-static system, I think.
I started with a washed medium-light roast, the Heart Stereo Blend. The GU64 seized but after it does the auto reverse and forward, it managed to start again. I was using 1000 RPM and for this lighter roast, they do suggest going 1200 RPM.
Retention wise on the first grind, it lost 0.3g, which is not bad considering there is no bellows like the DF64 (which has almost zero retention because of the bellows).
Taste wise, I am still fine tuning to this roast, which was a little bit sour and easy to be too fine. In fact, at grind 10, it took 32 seconds to get to 37g and there were some dark spots (concentrations) at the bottom of the Portafilter.
But it was less sour and has a better after taste than the Df64 espresso shot I made this morning with my Profitec GO.
I tried Grind 11 and it was a tad sweeter and got me to 28 seconds. I think I'll try 12 or 12.5 next to get it to That 23-25 seconds I tend to like with my Profitec Go.
One note, my Weber Blind Shaker fits and attaches to the magnet just fine, BUT I can't store it with the lid on underneath.
