How thick to make the sauce for beef Bourguignon is a matter of personal preference, but without a thickening agent, it will be thin and brothlike. Don't be intimidated by beef Bourguignon. It's really nothing more than beef stew -- albeit, with a delicious sauce laced with red wine, bacon and sauteed mushrooms. Flour, butter or even a long simmer make the rather wimpy sauce thick and velvety.
The Basic Recipe
Beef Bourguignon is a braised dish, which means the ingredients are cooked slowly with liquid in a covered pot. Because the pot is covered, any liquid that evaporates then condenses and falls back into the pan. As the beef cooks, it exudes some of its juices into the pan, creating even more liquid than you started with. As the dish continues to cook, the beef reabsorbs some of the liquid. Without extra help, though, a cooked beef Bourguignon stew won't be much thicker than when you started.
Make a Reduction
A simple, low-fat method of thickening the sauce is to reduce it. Transfer the meat, carrots and other ingredients to a warm serving dish and keep them hot. Heat the remaining broth in the pan to boiling -- without a lid -- and allow it to cook for 10 to 20 minutes, or until it has reduced by one-half and become slightly thickened. This sauce won't have the richness of a sauce thickened with flour and fat, but it has fewer calories and less fat.
Fancy French Methods
A beurre manie is the most common method for thickening this savory French stew. Beurre manie means "kneaded butter" in French, and the method is extremely simple. Whisk equal parts flour and butter together to make a thick, smooth paste. Roll small bits of the paste into teaspoon-size balls. Transfer the beef and vegetables to a warm serving platter. Add one beurre manie ball to the remaining hot liquid and bring to a boil, stirring gently. The butter coats the flour so it doesn't clump in the liquid, but instead melts into a thick, luxurious sauce. If the sauce is still too thin, add more beurre manie balls, until thickened. Allow the sauce to boil for at least one minute before you add another ball.
Try a Roux
Essentially the same as a beurre manie, a roux also thickens beef Bourguignon. A roux is a bit simpler to make in the beginning, but offers less control than a beurre manie. Melt butter or oil in a skillet or saucepan and whisk in an equal amount of flour, whisking constantly. Cook and stir the mixture over medium heat for at least one minute. The roux should be the consistency of wet sand and have a barely golden color. Slowly pour in the warm liquid from the stew. Bring the sauce to a gentle simmer, stirring constantly, until it thickens.