Citric acid is made from food-grade citric and deionized water. It is commonly used as a flavoring and preservative in food and beverages and is an excellent chelating agent—binding metals by making them soluble. Citric acid is also used for pH adjustment and is present in many insecticides and disinfectants to help destroy bacteria and viruses. Citric acid also removes and discourages the buildup of limescale from boilers and evaporators. It is also used in calcification removal process by removing calcium from water filtration membranes.