Phosphate soda is a type of beverage in which phosphoric acid

Phosphoric acid

Phosphoric acid, also known as orthophosphoric acid or phosphoric acid, is a mineral acid having the chemical formula H3PO4. Orthophosphoric acid molecules can combine with themselves to form a variety of compounds which are also referred to as phosphoric acids, but in a more general way...

 is included to give a flat sour taste. These beverages became popular among men in the 1870s in the United States, and phospate beverages were made with fruit flavorings, egg, malt, or wine. In the 1900s, the beverages became popular with both genders, and fruit-flavoured phosphate sodas were served at soda fountain

Soda fountain

A soda fountain is a device that dispenses carbonated drinks. They can be found in restaurants, concession stands and other locations such as convenience stores...

s, before losing popularity to ice cream beverages in the 1930s.