Stirring is a common cooking technique used to keep sauces from congealing. It involves using a spoon or other utensil to mix ingredients together in a circular motion. This motion helps to evenly distribute the heat and prevent the sauce from becoming too thick or lumpy. Stirring also helps to incorporate air into the mixture, which can help to create a lighter texture. The term 'keeps a sauce from congealing' can be summarized as stirring.