Cooking Class: Marinating

Marinating is a versatile and indispensable technique. It boosts the flavor of lean cuts of meat and also works wonders with vegetables and fruits. It doesn't require special equipment and involves simple steps to produce unfussy-but delicious-food.

Marinating, defined
It refers to soaking food (usually meat) in a flavorful liquid called a marinade. Marinating is a technique that's been around at least since the Renaissance, when acidic mixtures were commonly used to help preserve foods.

What marinating does
Ideally a marinade flavors, not tenderizes, foods. Though marinades are often purported to have tenderizing effects, the ingredients only permeate the surface of food and have little effect on the interior.

Best bets for marinating
Small or thin cuts of meat and poultry are generally good candidates. Larger cuts, such as roasts, may not benefit since they offer less surface area. Tender vegetables, such as mushrooms, zucchini, yellow squash, and eggplant, absorb flavor from marinades and taste especially good grilled. A brief stint works well for fish and shellfish, and it's beneficial, too, for some tender fruits, such as berries, orange sections, and melons. (When it's fruit that is being marinated, the technique is called "macerating.")

Marinade ingredients
Many marinades include an acidic element, such as citrus juice or vinegar, which boosts flavor and may tenderize the surface proteins of meat. Oil is another common constituent, as it coats food, carries flavor, and helps food stay moist. Robust ingredients such as garlic, soy sauce, and Asian fish sauce enhance the savory qualities of meats and fish.

Types of marinades
Perhaps the most common is the kind used to flavor fish or meat that is to be grilled or sautéed. Because these cooking methods only heat the meat to about 135 to 165 degrees, well below the boiling point of alcohol, these marinades should not contain wine, or the meat will taste of alcohol.

Wine is fine, however, for a second kind of marinade, one used for stews and braises, because these dishes are cooked for a prolonged period at a temperature that boils off the alcohol and eliminates any harsh flavor.

A third kind of marinade includes those that "cook" raw foods, usually seafood (as in the popular Latin dish seviche). Lime and/or lemon juice turns the flesh opaque and firm so it appears "cooked," but the food is actually still raw.

A fourth category of marinade is used to marinate cooked fish in a vinegar-based mixture to impart more subtle flavors. (This type of dish is called escabèche.)

Equipment
Because many marinades are acidic, it's best to soak food in a nonreactive container like those made of glass, ceramic, plastic, or stainless steel. Reactive metals such as aluminum or copper will respond to acids by discoloring the food and giving it a metallic taste. For easy cleanup, a zip-top plastic bag works well.

Safety concerns
Always marinate meat and fish in the refrigerator. You can use some of the marinade for basting after removing the meat or fish from it only if you bring the marinade to a boil and cook for five minutes to kill any bacteria.

Although the acid in a marinade appears to "cook" raw fish in seviche, it doesn't eliminate bacteria the same way cooking with heat does. When marinating fish that won't be cooked, make sure the fish is sushi-grade, or frozen-at-sea (FAS) fish; both are safe for healthy adults to consume raw.

Soak time
The length of time you marinate food depends on both the food and the marinade. Delicate fish, shellfish, and fruit usually soak for a shorter period of time (from 20 minutes to a few hours), while meats can go longer (up to a day or two). If, however, meat is soaking in a highly acidic marinade, its texture may turn grainy if soaked too long (more than a couple of hours, in most cases).

Season last
For our recipes that include added salt, we sprinkle it on after food is cooked instead of including salt in the marinade. That way, none of the salt is lost when the marinade is discarded. Seasoning after the food is cooked also allows the small amount of salt we use to have a bigger impact on the overall taste.