There are two basic types of coffee grinder available: A blade grinder and a burr grinder. Burr grinders use grinding wheels to crush coffee beans, which are adjustable for grinding from course grinds to very fine grinds. The fully adjustable grind control will depend on the machine you areusing to make coffee, or the type of coffee you enjoy - course grindsare needed for filter coffee makers and very fine grinds are needed forespresso.
The coffee only passes through the grind cones once so it preservesthe flavour of the coffee. Burr grinders are generally seen as a moreprofessional approach than blade grinders although they are more expensive. If you enjoy espresso coffee, paying a little extra for one of theseis well worth it. Burr grinders are not suitable for spices. Blade grinders use blades to chop and grind the coffee beans.
The longer you hold the button down, the finer the grind will be. They are less expensive than burr grinders although they can benoisier. This type of grinder can also be used as a spice grinder, although itcan affect the taste if it is subsequently used for coffee without proper cleaning.