Grinding is the preparation phase to brewing coffee, which is also known as milling. The method of brewing greatly influences the type of grind, because the fineness of the grind heavily alters the taste of the coffee. While the brewing process exposes the ground coffee to heated water, the thickness of the grind impacts the time of that exposure. For example, beans that are ground too finely will expose too much of the bean to the heated water resulting in a bitter and almost burnt taste. A grind that is too thick or coarse will make the coffee taste weak and watered down. It is for these reasons that the grind be matched to the brew and that the grounds be as uniform as possible for the best taste.
There are four categories for brewing coffee: burr, chopping, pounding and roller. Many baristas have studied this art of making coffee and have discovered that coffee taste its best when ground immediately before brewing. The reason is because once ground, much of the surface areas of the bean is exposed, releasing the aromas and mixing with the oxygen. While it may smell delightful, it releases the flavors and removes the taste. So, if you are looking for that perfect cup to wake up your day, grind right before its time.