There are two types of coffee grinders: with burrs and with
blades. They work totally different.
Grinder with blades actually doesn't grind. It cuts coffee beans
again and again until wanted consistency is achieved.
Burr coffee grinders crush coffee beans between two surfaces
(burrs). With a burr coffee you can achieve much more even grind,
thus better coffee.
Many burr grinder offer a wide range of grind settings, making
them suitable to grind coffee for various brewing systems such as
espresso, drip, percolators, French press, and others. Many burr
grinders, including almost all domestic versions, are unable to
achieve the extremely fine grind required for the preparation of
Turkish coffee;traditional Turkish hand grinders are an
exception.but the blade grinder can not offer this function.