I need to get a coffee grinder. What kind is best? I have heard that burr mills are better; are they worth the extra cost? Which ones last longer?
Update: I ended up getting a Hario hand grinder.
The folks at America's Test Kitchen did a review of coffee grinders and found that the burr mills didn't result in superior consistency to blade grinders.
They found that if you stop grinding every now and then and shake the coffee grinder and grind for a total of 25-30 seconds, you get the best results.
From the video review:
"Lots of people said that these blade grinders chop the beans unevenly. They also said they heat up the beans more because of the friction and that degraded the flavor of coffee. I had dozens of people tasting this coffee and no one picked up flavor differences between the blade-ground and the burr-ground. There were differences in the body but not the flavor... and we found a way to use the blade grinders to match that body.
From the text review:
"We found we could improve the evenness of the blade grind either by grinding in short, quick bursts, with stops in between to shake the grinder to redistribute the grounds, or by shaking the grinder as it ground, much as you would a martini in a cocktail shaker."
Their favorite was the Capresso Cool Grind, Model 501.
They did note that you will need a burr grinder for espresso.
It depends on what kind of coffee you want to make. If you are making espresso and you're going with a more expensive machine, you'll want to spend some cash on a nice burr mill grinder as well (this will be able to achieve a more consistent grind and result in tastier espresso.
If you are just using a drip or a french press and need a coarser grind, then a regular blade grinder will do nicely. In my experience, you can get a finer final grind from a blade grinder, but it won't be as consistent in the grinding. For a drip or a french press, this isn't such a big deal. However, you don't want to grind too much with a blade grinder or you'll burn the beans and mess up the taste of the coffee.
It sounds like this is for home use, if it were for a coffee shop, you need a burr mill so you can get all the coffee ground uniformly and to be able to vary the grind.
For home use, a burr mill gives you that same uniformity and control over the grind, but they do sometimes need the wheels replaced and they're typically more money. You might be able to use one of the cheaper rotating blade grinders, but you can't get a good medium or coarse grind with them, and you won't get a uniform grind. If you always want a fine grind, they can be good enough.