Grind coarseness is important because it determines the taste of your coffee. Bad coffee is a result of too much extraction time or over-extraction from the bean, tasting burnt or bitter. While under-extracted coffee may taste weak or acidic. The coarser grind, the better for French Press; the finer, the better for Bee House. The coarseness of the grind allows you to control how your coffee tastes by having a thorough, balanced extraction with the right amount of time.