The crossword solution for the term IN A STIR is FERMENT, which is a seven-letter word. Fermenting is a process in which microorganisms such as yeast or bacteria convert carbohydrates into alcohol or acids. This process is used to make beer, wine, and other alcoholic beverages, as well as bread, yogurt, and other food products. Fermenting can also be used to create a reaction that causes a stir, such as when making kombucha or sourdough starter.