Things You'll Need
Fork or tenderizing hammer
A marinade works chemically on sirloin steak, along with poking holes in the surface of the meat, to tenderize it. The marinade also flavors the steak. Plan ahead so you have time to let your steak marinate for at least two hours. You can even put the steaks in the marinade the night before. Marinated steaks are especially good on the grill, where the excess can drip off into the coals. This way, the steak takes on a nice crust, which holds in the juice and provides you with a nice, tender steak.
Choose an acidic liquid for your marinade. These include citrus juice, vinegar, wine and tomato products. The acid helps break down the fibers in the meat. Add 1 cup of acidic liquid in a bowl.
Add 1 tsp. salt to the marinade. This helps the meat retain juice, which may be lost in the acidic marinade.
Spice your marinade as desired. Traditional sirloin flavorings include Worcestershire sauce, brown mustard, garlic, onion and Italian seasonings.
Use a fork to poke holes all over the surface of the meat, or pound the meat with a tenderizing hammer. The holes allows the marinade to penetrate and tenderize the inside of the steak without the outside becoming mushy.
Submerge the steak in marinade, cover and refrigerate for at least two hours and as long as overnight. The acid will penetrate the holes and break down the fibers to tenderize the meat prior to cooking.