JojoS wrote:You gave the impression in your original post that the problem occurred only with your home roasted coffee using the Behmor 1600 and not with commercial roasted coffee that you buy fresh. Reinstalling the burrs sounds like a good idea. The usual advice is to rotate the burrs so that you screw it down on a different hole as before and see if you can choke your shot with a fine setting.

Sorry, I wasn't very clear. He was able to choke my machine with his Lido 2 with my home-roasted coffee, so at least in part it's the grinder. But the fact that I can grind good shots with cafe-bought inclines me to think that I also need to work on my roasting. After taking some advice, my most recent roasts seem to be a lot better. Gonna stay away from the kenyans and guatemalans for a bit while I continue to learn.

Dude,

Thanks for this thread. The replies have been very informative. I do not own a Behmor, but I do own a 1 kilo electric roaster ( Torrefattore ) made in Isreal. My drum is powered by a gear reduction motor rated at 40 RPM. I also use a small stainless steel roaster that I Manually spin at 40 rpm or so over a propane camp stove. The higher rpm will give you a more even roast with less chaff sticking to the beans. Your picture looks like beans could use a little more time.

I roast my coffee to the second crack, and not a second longer. They don't pop oil that way, they don't clump in my porta-filter, and they are 95% chaff free by that time. I have had gushers on numerous occasions, usually operator error through incorrect dosing and grinding. Old stale beans will do it every time though. I assume that the cell structure changes as the roasted bean loses its oil/moisture.