Colas, sodas and beers are known to be among the most acidic beverages consumed in modern society, the acidic nature of sodas (pH ∼3) is derived from conversion of dissolved CO2 to HCO3− and H+ by interaction with H2O as well as additives such as citric acid and phosphoric acid.
Acids are added to beverages and compose a flavor profile giving the beverage a distinctive taste. Acids provide a tartness and tangy taste that helps to balance the sweetness of sugar present in the beverage; they are key factors in the taste of the beverage. Human saliva is almost neutral (pH approximately 6.8), and when human taste receptors interact with acids in food or drink this sensation is perceived as sourness. Acids also play an important role in the natural preservation of soft drinks.
The most common acidulants in soft drinks are citric acid and phosphoric acid.
Phosphoric acid is added to cola drinks to impart tartness, reduce growth of bacteria and fungi, and improve shelf-life. Phosphoric acid can strengthen the acidity. It has the same characteristics as the cola flavors, which are dry and sometimes balsamic.
Citric acid, a substance naturally occurring in citrus drinks and added to many others, imparts a tangy flavor and functions as a preservative. Malic acid is used when strong flavor enhancement is required and mostly in combination with citric acid.
In addition to phosphoric and citric as the major acidulants, some other organic acids such as tartaric, malic and ascorbic acids have special uses in the carbonated soft drinks industry.
The importance of acid in carbonated beverages
