Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a weak acid with the chemical formulaH3PO4. It is normally encountered as a colorless, syrup of 85% concentration in water.Phosphoric Acid Food Grade isused as an ingredient in foods and beverages. Phosphoric Acid is typically used for pH control in the food industry, for example in the manufacture of cheese products, fats, and shortenings.