Since buttermilk is already fermented, it has a much longer shelf life than regular milk, but the fresher your buttermilk, the better. If the expiration is approaching and you haven't yet used the buttermilk, you can freeze it for up to two months. Place the entire container in a large, sealed plastic bag. When you defrost it, use the buttermilk for cooking and baking instead of drinking.

Using buttermilk in baked goods adds more than just flavor. Buttermilk is more acidic than regular milk, so when it encounters a base, like baking soda, it creates gas bubbles. Buttermilk pancakes are slightly tangy and the bubbles make the pancakes fluffy and tender. This ingredient makes for moist and flaky biscuits and pie crusts as well. For baking purposes, choose recipes that call for buttermilk rather than substituting it for regular milk, and balance the acidic nature of buttermilk with baking soda in order to create a properly risen finished product.

Buttermilk not only adds flavor to a meat dish, but it's a very effective tenderizer. According to "Fine Cooking" magazine, the calcium in buttermilk and other dairy products breaks down the tough proteins in meat. Use it as a marinade for your favorite type of meat, or substitute buttermilk ranch bottled dressing for more complex flavor. The length of time you should soak the dish depends on its texture. A delicate filet of fish only needs to soak in buttermilk for a few minutes, while chicken can be left marinating in buttermilk for up to two days in the refrigerator. Once you've marinated fish or chicken, dredge it in seasoned flour and cook it in hot oil to create moist and tangy fried fish or chicken.

The creamy texture and tart taste of buttermilk means it can be used as a tasty alternative to milk in certain dishes. Mix buttermilk or buttermilk ranch dressing into cooked potatoes along with butter, salt, pepper and chives for a slightly grown-up version of mashed potatoes that kids will still enjoy. Buttermilk will also add a tangy note to a casserole of macaroni and cheese. If you prefer a more subtle flavor, substitute only half the amount of the milk your recipe calls for with buttermilk. Get the tang and taste of buttermilk with more convenience by keeping dry buttermilk dressing mix on hand to use for dressing or a seasoning mix when you want it.