This is a tough question to explain to someone without showing them. Each style of coffee brewing has its own optimal grind requirements. The three most common grind types are fine, medium, and coarse.
Coarse - A coarse ground coffee is primarily used for the french press
Medium - A medium ground coffee is what is required by drip pots and vac-pot brewers. There are different degrees of medium depending upon filter type.
Fine - Espresso requires a fine grind in order for the extraction to be perfect. Turkish grind coffee is slightly finer than espresso.
| Drip coffee makers (flat bottomed filters) |
Medium |
| Drip coffee makers (cone filters) |
Fine |
| Plunger pot / French press | Coarse |
| Percolator | Coarse |
| Espresso machines (pump or steam) |
Extra fine |
| Espresso moka pots | Fine |
| Vacuum coffee pot | Coarse |
Information Sources: I Need Coffee and about.com and Image Source: about.com
Grinding
Burr Grinder | Blade Grinder | Grinding Overview
Java
Drip Brew | French Press | Percolator | Vac Pot | Chemex
Turkish | Pour-Over | Instant | Espresso | Water Quality | Java Overview