Why marinate?

For me, there’s only one reason, and that’s to add flavor. You may think of marinating as a way to tenderize meat, but in my opinion, that’s a bad idea. Marinades “tenderize” by using some sort of acid, such as vinegar, wine, citrus juice, or buttermilk, which breaks down the protein in meat, softening its connective tissue, but an acid marinade actually diminishes meat’s ability to retain moisture, thereby drying it out. Bad trade-off. Commercial meat tenderizers contain enzymes that can turn meat to mush, hardly a better choice. If you’ve got a truly tough piece of meat, you are much better off making it tender and succulent by using a slow, moist cooking method, such as braising or stewing (see Pot-Roasting lesson). Alternatively, you can tenderize tough cuts by pounding them with a meat hammer or even with the bottom of a heavy skillet.