Most people already know that the fresher the grind, the better tasting your coffee will be.  So you should always grind your beans fresh right before you brew your coffee.  That’s basic, but there’s more to it.

Grind consistency

As a general rule of thumb, the shorter the brewing time, the finer the grind needs to be.  So for espressos, which brew in seconds, the grind need to be quite fine. Home coffee makers require the grind to be a little coarser.

All grinders are not created equal

The best results come from grinders that use discs to shred the beans, instead of blades that chop them. These grinders are called burr grinders, and although they are a little more expensive, they produce superior results. If you’re serious about your coffee you should look into a burr grinder.

Burr grinders don’t heat the beans as they grind them.  Blade grinders, on the other hand, heat up the beans as they chop, and the flavors that should be seeping into your water are actually released into the air before you even start your brew.

If you own a blade grinder, grind your beans in quick bursts so the beans heat up less. Quicker bursts means less friction and better taste. Try grinding no more than ten seconds at a time.
A variety of coffee grinds from coarse to fine

Keep it clean

No matter which type of grinder you have, make sure to keep it clean. If you don’t, residual grinds will get into your coffee the next time you use it. Clean your grinder after every use, just as you would your coffee maker or espresso machine.

Grinding for espresso

Espresso passes through the brew head in 30 seconds or less, depending on the machine. That means, with espresso in particular, the home barista needs to pay special attention to the grind.