• Blade Grinders
That high-speed whir heard round the world each morning is a blade grinder. These are the cheapest grinders for general-purpose coffee making. They come with perky names like Krups or Braun. You probably have one. You shouldn’t. Perhaps you should relegate it to grinding Grandpa’s gruel. They can be very handy but they are not always precise and I do not recommend them. They horribly hack and slice your beans, leaving an uneven grind with course and fine particles in the same batch. The motors run hot; grinding too long can scorch the coffee.
• Burr Grinders
For a step up in precision, now we're moving in the right direction, tally-ho! Burr grinders are the answer to a more perfect union of bean and grind. Disk (a.k.a. plate) and conical burr grinders are your basic choices. Flat disk grinders use two spinning disks to smash the coffee into precise uniform grinds. Precision is good for home use; you can even get a truly fine espresso grind. But, alas, they can also run hot and, if not careful, can scorch the beans.
• Conical Burr Grinders
These are a bit more expensive, but are the choice of both coffee professionals and enthusiasts alike and well worth the price. These are the workhorses. Precision grinds, even for Turkish coffee, and a slow, cool motor.
• Hand Grinders
If you’re both counting pennies and are also in need of a way to work out your flabby upper arms, perhaps you could try a hand grinder. They work on the same principle, except your arm substitutes for an electric motor. Watch those biceps bulge! The trouble here is that it takes an awful lot of effort to get even a small brew under way and in that time you could be drinking coffee.
The Various Grinds:
This type of grind leaves the largest granules of coffee and is preferred for French Presses (a.k.a. plungers) or the percolator method of brewing.
Medium grinds have a consistency of granulated sugar and are primarily recommended for vacuum and certain types of drip coffee makers. Because of its versatile size, it can also be used for other brewing methods, but not espresso.
Also known as an espresso grind, this is a grind with a powdery/mealy consistency used in espresso makers and Neapolitan flip-drips though electric drip and filter brews can use it as well.
Like fine flour, this extremely fine grind is the province of Turkish coffee and usually needs to be ground in a special grinder.