Ground coffee is coffee which has been prepared for brewing by being crushed or ground. When hot water is passed through the ground coffee, it extracts compounds within the coffee beans, resulting in a brewed cup of coffee. There are a number of different ways to process coffee for brewing, and it is important to match grinding method to brewing method to ensure that coffee comes out with good flavor and high quality.
One method of grinding is to use a burr grinder, which crushes coffee into pieces of uniform size. Blade grinders are also used to chop the beans into small pieces, and coffee can also be run through rollers or pounded. All of these methods tend to release oils and volatile organic compounds, making it critical to brew the coffee as soon as possible after grinding to capture the flavor. At some coffee houses, coffee is ground on demand, so that cups are brewed with coffee which has been ground seconds ago.
Before coffee can be ground, it has to be roasted. When coffee beans are harvested, they are first allowed to cure, and then submitted to a roasting process which can vary in length and intensity, depending on what the coffee will be used for. The quality of the beans and the handling during the roasting process determines which applications the coffee can be used in, and determines how much caffeine will be present in each cup.
The finest grind is Turkish coffee. This type of ground coffee must be very even and very small to brew traditional Greek and Turkish coffee drinks. The coarsest grind is coffee intended for French press or percolator use. Using this coarse grind with Turkish brewing techniques would result in a weak, gritty cup, while using Turkish grind in a French press would result in an overextracted cup with a bitter, sharp flavor.
For people who can grind coffee at home, ideally coffee beans should be stored in a cool dry place and ground when they are needed. If people purchase ground coffee at the store, they should try to keep it airtight, and store it in a cool dry place. While the freezer is a popular storage location for coffee, freezer storage can actually negatively impact flavor, and is not recommended.
Many people have learned that different roasts and beans yield very different flavors. When preparing ground coffee, people can blend beans from different locations if they want to create a customized flavor.
