The function of cooking is to tenderize food. In the case of meat, heat turns connective tissues into gelatin. With really tough cuts, cooking alone offers only a partial solution to the problem of toughness. This is where marinade steps in.

Marinade contains enzymes and acids that further break down connective tissues in meat. This use of marinade has been understood and applied for centuries in Europe, Asia and the New World.

Connective tissue in meat that comes in direct contact with protein-digesting enzymes gets partially broken down. Unfortunately these tenderizing enzymes also reduce the capacity of the meat to hold juice. Marinating can result in too great a fluid loss and thus, while the result is tender, it can also be less juicy (drier!)

Protein-digesting enzymes are heat-activated at temperatures of from 140 to 175 degrees but deactivate when they reach their boiling point. When we let meat sit in marinade at room temperature, we are not achieving a tenderizing function but simply enhancing the taste.

For tenderizing to occur, direct contact is necessary between meat and marinade. Soaking meat allows only shallow penetration into the surface of the meat. The danger in marinatating large or thick cuts of meat is that the surface will become mushy while the center remains tough.

Puncturing the meat is not a solution as little marinade penetrates to the interior but large amounts of juice are forced out through the holes, resulting in an even less balanced tenderness.

The favored solution is to marinate flat cuts of meat so that tenderization will be even and consistent. Meat may be placed in a plastic baggie (Food grade bags only! Shopping bags, lawn bags and garbage bags will leach chemicals you don't want in your dinner!) Place the meat inside the baggie, squeeze out as much air as possible and rotate frequently so that all surfaces benefit from the use of the marinade.