It depends on the recipe and the type of alcohol. If you add alcohol to a dish just before serving, such as in Cherries Jubilee, 85 percent of the alcohol remains. When you cook the dish 20 minutes, about 35 percent of the alcohol remains. If you add wine, for instance, to a slow-cooked dish such as Beef Daube Provençal that cooks for a couple of hours, only about 5 percent of the alcohol (but all of the flavor) remains.