Citric acid is a chemical commonly used to give a sour taste / regulate the acidity of a food or drink. is a food additive to give a sour taste. Physical Specs Colorless or white crystalline granule or crystalline powder, odorless; salty and cold taste, soluble in water, pH7.5-9 in 5% solution, when heated to 150 ° C can lose water crystals. commonly applied to: Food additives, flavor enhancers, coloring, preservatives, detergents. cleaning, pharmaceutical, cosmetic, industrial and chemical process.