**TL;DR – Making coffee is quite a scientific process and freshly grinding your beans will help to make your cup ‘o joe the best it can be. Multiple variables in the brew process could affect the quality of your coffee – freshly ground beans make an important difference.** Coffee beans go through a long roasting process that is calculated for the type of coffee, origin, and flavor goals. There is a series of chemical reactions that take place and properly storing and grinding beans helps to make sure that only the necessary ones happen. As soon as you grind coffee, it oxidizes and alters the flavor. Coffee beans have oils in them that are essential to their quality, so oxidation allows the moisture in the air to dissolve the water soluble oils instead of having them contribute to your brew. CO2 is important to the aroma and taste of coffee – it also explains the crema on top of espresso that eventually disappears after it sits for too long. It escapes from coffee beans very fast after grinding them. Ever try to make a decent shot of espresso with the classic, pre-ground, red canister Folgers? It does not work. Grinding coffee makes it cover more surface area. Beans are easier to store and pre-grinding makes the aforementioned processes happen tremendously faster. Along with scientifically perfecting your brew, not having pre-ground beans gives you further control over your grind size. https://soloespresso.net/fresh-ground-coffee/