When exposed to air, coffee beans will oxidize. Coffee grounds suffer this more so because they have a larger surface than the beans and lack the beans protective skin. Home coffee grinders allow you to stop the level of exposure and produce the freshest grind. Most importantly, grinding can be done when you need it.
Everything has a price, though. Picking the best grinder can make the messy and long process of grinding much more rewarding.
There are three main types blade, crusher and burr. The crusher is the ancient way of using a pestle and mortar to mash the beans. This process is difficult and gives an uneven grind because it just crushes them not highly recommended. Blade grinders chop. The blade whirls, slicing the beans into small grounds still not the best because the grains are not the same size and not all the oils are released, varying the flavour and dissipating a lot of the flavour. However, burrs use motorised plates with teeth that are pyramid in shape, allowing for the perfect grind. Better burrs allow for varied grain sizes because the speed can be adjusted accordingly.
The burr allows for the perfect brew. Speed control...