Phosphoric Acid
What it does
Acidity in colas.
How it's made
Manufactured from phosphate rock.
Phosphoric acid is a strong mineral acid best known as the sharp, tangy acid in cola drinks; it is also used to acidify other foods and as a starting point for making phosphate salts. Unlike the fruit-derived acids, it is an inorganic acid manufactured from mined rock.
It is produced from phosphate rock, a mineral dug from the ground. In the common "wet process", the rock is treated with sulphuric acid, which releases phosphoric acid and leaves behind calcium sulphate (gypsum) as a by-product. For the highest-purity food and drink grade, a "thermal" or purified process is used, in which phosphorus is burned to phosphorus pentoxide and then dissolved in water, or the wet-process acid is thoroughly purified.
The crude acid is cleaned to remove fluorine, heavy metals and other impurities before it can be used in food, since the starting rock naturally contains trace contaminants. The purified, food-grade acid is then diluted to the required strength — a clear, syrupy liquid ready for use in soft drinks and food manufacturing.
Possible reactions
High intakes linked to lower bone density and dental erosion.