Marinating beef allows flavor to evenly coat the surface, and cooking it in a Crock-Pot makes the meat tender and juicy. Together, these methods allow for the use of inexpensive cuts of meat with delicious results. Contrary to popular belief, marinades do not make meat more tender, but they do add flavor, according to Andreas Viestad of the "Washington Post." It is not necessary to marinate beef for a long time, but marinating and cooking with the same flavors will result in a delicious dish.
Choose a cut of beef. According to Christopher Kimball of "Cook's Illustrated," inexpensive roasts from the chuck, round or sirloin are best when cooked at low temperatures, making them ideal for use in a slow cooker. He recommends a blade roast from the chuck or shoulder of the cow for the best texture and flavor. Make sure the meat will fit into the Crock-Pot, either whole or cut into two or three large pieces.
Prepare a marinade by mixing oil and an acid such as vinegar. Seasonings will dissolve in the oil and vinegar, and the liquid helps them evenly coat the meat. Beer or wine can be used instead of vinegar, which may reduce the presence of cancer-causing compounds in fried or grilled meat, according to a study at the Universidade do Porto in Portugal.
Add the spices of choice to the marinade. For a Mexican dish, include crushed garlic cloves, chili powder and cayenne pepper or crushed red pepper flakes. For an Asian-inspired meal, try five-spice powder, ginger, garlic and soy sauce. Include salt in any marinade, as it will be absorbed by the meat more than other seasonings during the marination process and bring flavor more deeply into the roast.
Place the roast in a large plastic storage bag. Pour the marinade over it. Put the closed bag in a refrigerator overnight. Starting marinade the night before makes it easy to put the roast in the slow cooker first thing in the morning for dinner in the evening.
Remove the roast from the marinade and transfer it to the slow cooker. Discard the marinade. Add chopped vegetables of choice to the Crock-Pot. Include additional crushed garlic and a large sliced onion. Sprinkle additional spices over the meat, and pour 1 can beef broth, red wine, water or a combination of those over the beef.
Cook the beef on low heat for 11 to 12 hours or on high heat for five to six hours. Cooking time will vary depending on the size of the roast and the slow cooker.
Shred the beef to serve on sandwiches or tacos, or add chopped vegetables and beans to make chili or stew.