Citric Acid

Citric Acid is a naturally occurring weak organic acid commonly found in lemons, oranges, limes and other citrus fruit. Citric acid is also produced as a by product of the citric acid cycle during metabolism in living organisms. Its also a natural preservative and added to food producing an acidic or sour taste.

At room temperature citric acid appears as a white or clear crystalline solid. It melts at 156oC and boils as 310oC. Citric Acid will dissolve in water; this process is endothermic and reduces the latent temperature of the water as the entropy increases. The molecular formula for Citric Acid (anhydrous) is C6H8O7.

Citric Acid was first isolated in 1784 by Carl Wilhelm Scheele who managed to crystallise it from lemon juice. It was later found that Citric Acid is produced by Penicillium Mold from sugars. Pfizer began industrial production of Citric Acid in the early 1900's using this very same process. This production technique is still used today and produces much of the Citric Acid used in industry.