In general, I prefer burr grinders for grinding coffee beans, but sometimes I have to use a rotary grinder. I'd like to understand how to best use the rotary grinder for grinding coffee beans.
I find burr grinders generally produce a superior result in terms of grind consistency, less heat generated, and therefore final product is better. Sometimes in a pinch, however, I need to use a rotary grinder (e.g., it's the only grinder around; burr grinder hopper is full of other beans; flavoured beans that I don't want to pollute the burr grinder; testing to see if a newly roasted batch of beans is "ready", etc.) -- and there are some advantages of rotary grinders.
I'd like to use the rotary grinder in such a way as to make the ground coffee particle size as even as possible. Is this even possible? I find that, no matter how I use the thing, I end up with some very large chunks (even whole beans) and some extremely fine powder. The result is only usable in filter coffee (drip/pour-over), but it simply doesn't "work" as well as when the ground coffee particle size is more even.
I have searched for techniques or recommendations, but I find exactly nothing helpful on this, but I believe there must be some way to optimize the use of a rotary grinder. I have tried things like...
- Pulsing the machine. Turning on for a second, then letting the blades come to rest, then pulsing some more, until I achieve approximately the grind I'm looking for;
- Shaking the grinder up and down during the grinding;
- Revolving the grinder around in a circle the opposite way that the blades are spinning;
- Using more or less beans in a single grinding session ("half full" seems to work best for me)
All of these seem to have minimal / marginal benefit. Is there any way to improve the coffee bean grind consistency using a rotary grinder?