citric acid is naturally found in citrus fruits. It easily mixes into liquids, making it a valuable acid. Lemons and limes have high concentrations of citric acid, accounting for their bitter taste. Oranges and tangerines are also high in citric acid, though lower than the more bitter citrus fruits. You can find citric acid present in certain berries too, particularly raspberries and blackberries. The ability of citric acid to bond with other minerals can make it helpful in softening water. Soaps and laundry detergents can be more effective when they contain citric acid. It can work well in shampoos because it tends to remove excess minerals from the water.