When it comes to substituting beef stock in a recipe, there are many options, including beef bouillon, beef broth, vegetable or chicken broth, red wine, beef base, or a combination of soy sauce and water. The specific substitution will depend on how it is used in the recipe.
Beef stock is a rich, flavorful liquid made from the roasted bones and bits of meat from a cow. Recipes that call for beef flavor are limited in what can be used as a substitute. In general, only beef bouillon, either in granule or cube form, beef broth or beef base will work as a substitute. Beef broth works well, but is more watered down, as is bouillon. Beef base can impart a strong, beefy taste, but is high in sodium.