What is a marinade?
Marination, also known as marinating, is the process of soaking foods in a seasoned, often acidic, liquid before cooking. The origins of the word suggest the process of use of brine (aqua marina) in the pickling process, which led to the technique of adding flavor by immersion in liquid. The liquid in question, the marinade, is often a vinegar (or other acidic liquid such as lemon juice or wine) and oil mixture. It can also contain herbs and spices.
Marinades are commonly used to flavor foods and to tenderize tougher cuts of meat or harder vegetables. The marinating process may last just a few seconds or for several days. Different marinades are used in different cuisines.
In meats, the acid causes the tissue to break down, allowing more moisture to be absorbed creating a juicier end product. However, too much acid can be detrimental to the end product. A good marinade has a delicate balance of spices, acid and oil.
Often confused with marinating, "macerating" is also a form of food preparation. Often soft vegetables, legumes or fruits are used and are also coated in a liquid. This process, again, makes the food tastier and easier to chew and digest.