Tartaric acid is primarily used in the food industry to make baking powder. Baking powder is a leavening agent used in baked goods, such as cakes and bread, to help them rise and become fluffy. Tartaric acid is one of the main components of baking powder, along with sodium bicarbonate (baking soda). When baking powder is added to a batter or dough and exposed to heat, the tartaric acid reacts with the baking soda to produce carbon dioxide gas, which causes the mixture to expand and rise. This creates the fluffy texture that we associate with baked goods.
While tartaric acid is not commonly used to remove rust or as a drying agent, it is sometimes used in the wine industry to adjust the acidity of wines and as a flavoring agent in some soft drinks and fruit juices. However, its primary industrial use is in the food industry as a component of baking powder.