The Real Reason You Should Use Freshly Ground Pepper
Black pepper comes in two varieties and if you're on a budget, typically, ground black pepper is significantly cheaper, while peppercorns are on the pricier side. So why is there a premium placed on whole peppercorns? And what's the benefit of grinding them yourself rather than having the manufacturer do it for you?
When pepper is freshly ground, it's significantly more flavorful than pre-ground pepper. Part of the reason that ground pepper seems to lack flavor compared to freshly ground pepper is that the ground variety oxidizes once it's in the can or the spice shaker (via Epare). Oxygen reacts with some of the flavor compounds in pepper causing it to lose its flavor. In addition, the oxidation process can cause pepper to lose some of its health benefits as well, which include everything from helping digestion and the cardiovascular system, as well as fighting infection.
When you grind pepper immediately before eating, the ground pepper has significantly less time to react with the oxygen, which allows it to maintain the flavor components that make it peppery.
Controlling the grind yourself
In addition to the spice associated with black pepper, when it's freshly ground, it also tends to have a fruity and bright hint to it (via Simply Recipes).
When you grind pepper yourself, you can also determine how coarse the grains are. Sometimes the texture of ground pepper can play a large role in a dish. For example, cacio e pepe, the famous Italian black pepper and cheese pasta, is generally prepared in Italy with finely ground black pepper (via Gimme Some Oven). On the other hand, if you're going to use pepper to crust a steak, you're going to want to use a significantly coarser grind. While pepper grinders can come in a number of varieties from sleek modern metal ones, to wooden ones that look like a table leg, they all tend to have a silver knob, which is the gadget responsible for determining the texture of the grind. The rest is up to you!