Make almost any cut of steak flavorful and tender with the right marinade. Tougher cuts, like skirt steaks and flank steaks, become moist and tender after marinating, while even prime cuts like a sirloin or porterhouse benefit from an infusion of flavor. Whether you prefer simple ingredients -- like olive oil and salt -- or a big flavor --- such as an exotic blend of pureed fruit, honey and spicy pepper -- customize a marinade to fit your menu.

Most marinade recipes include an acid, which tenderizes meat. The acid denatures the protein, which helps break down tough fibers. Lemon juice, buttermilk, yogurt, vinegar and tomato juice all have this effect. The enzymes in fruit can also tenderize steak by breaking down fibers. Pineapple works well but it may over-tenderize, while kiwifruit tenderizes without turning the meat mushy. For the best results, use pureed fruits.

Although acid and enzyme ingredients may add flavor, the major punch of flavor comes from seasonings and spices. Oil is sometimes added to a marinade to help carry the flavor into the meat, but it's not necessary if the steak is well-marbled with fat. Black pepper, salt, garlic powder, dry mustard and rosemary are just a few seasonings to include. You may also incorporate fresh ingredients, such as garlic and onions, and sauces, such as soy, Worcestershire, mustard and barbecue. For sweetness, add molasses, honey, sugar or brown sugar.

The proper ratio of ingredients in a marinade is key to the best flavor and tenderizing effects. For a basic marinade, use one part each of an acid ingredient and an oil, such as olive oil or canola. Add up to one part of aromatic flavor ingredients, such as chopped onions or fresh herbs. Mix in salt, pepper and sugar to taste. If you prefer to use an enzymatic tenderizer, skip the acid and add 1 to 2 tablespoons of fruit to every 1 cup of marinade. After mixing up the marinade, reserve ½ to 1 cup of it in a separate container for basting.

Safety is a key concern when handling raw meat. Marinate steaks in a sealed container in a 40-degree Fahrenheit or cooler refrigerator. Marinate for at least four hours and as long as 24 hours for the best flavor. Dispose of the leftover marinade -- which has been in contact with the raw meat -- and use only the untainted reserved marinade for basting or serving. When handling raw steak, wash your hands with soap and water both before and after, and clean all preparation and cooking utensils to prevent cross contamination.