For over 70 years, the "phosphated soda" ruled the soda fountain and then in the late 1950s the Phosphate disappeared. Fifty years later Acid Phosphate, the ingredient that made the phosphate unique, has returned.
The tongue tingling sensation and dry tart flavour are what make Acid Phosphate distinct from other soda acids, like citric acid.
Acid Phosphate is more than just diluted phosphoric acid, it's actually a partially neutralized solution made with salts of calcium, magnesium and potassium. The solution has a pH between 2.0 and 2.2, or about the same as fresh squeezed lime juice.
Some of the most popular soda fountain drinks included the Cherry Phosphate and Chocolate Phosphate, while the local saloon touted the Angostura Phosphate as the perfect remedy for the previous days excesses. There are literally hundreds of phosphate style drinks that haven't been tasted for decades, waiting to be rediscovered.
Acid Phosphate can be used in cocktails to enhance the sour character. Because most cocktails use lemon or lime juice to balance sweetness, there is a tendency for many drinks to taste similar because of the fruity character of the citrus juice. Acid Phosphate is a perfect way to change the character of a drink.
More info on Acid Phosphate via Art of Drink
A soda is not a phosphate unless it uses Acid Phosphate.
Size: 250ml (8 oz) bottle, which is enough to make 40 to 80 drinks.
Usage: ½ to 1 tsp of Acid Phosphate per drink