Why is there different coarseness of ground coffee?
How fine or coarse your coffee should be ground depends on the brewing method. In the conventional drip-brewer, the coffee should be to a medium grind. In the “Italian” espresso coffee maker, water is boiled to steam and the steam is pushed through the coffee. This calls for a much finer grind to ensure as much coffee solids are absorbed by the steam as possible. In the “coffee press”, hot water sits on the ground coffee for minutes. This calls for a much coarser grind to ensure that there isn’t an overextraction of coffee solids given the amount of time the water and coffee are in contact. Overextracted coffee can look like sludge if a medium or fine grind is used.
