Citric acid is a weak organic acid. It is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks. Citric acid exists in greater than trace amounts in a variety of fruits and vegetables, most notably citrus fruits. Lemons and limes have particularly high concentrations of the acid; it can constitute as much as 8% of the dry weight of these fruits. The concentrations of citric acid in citrus fruits range from 0.005 mol/L for oranges and grapefruits to 0.30 mol/L in lemons and limes. At room temperature, citric acid is a white crystalline powder. Citric acid is commonly employed in wine production as a substitute or improver where fruits containing little or no natural acidity are used. It is mostly used for inexpensive wines due to its low cost of production. Citric acid is one of several acids used by home brewers to modify brewing water for making beer.
As a food additive, Citric Acid is used as a flavoring and preservative in food and beverages, especially soft drinks. Citric acid can be added to ice cream as an emulsifying agent to keep fats from separating, to caramels to prevent sucrose crystallization, or to recipes in place of fresh lemon juice. It has use in culinary applications where an acid is needed for either its chemical properties or for its sour flavor, but a dry ingredient is needed and additional flavors are unwanted (instead of vinegar or lemon juice).