Premix and postmix are two methods of serving – usually

carbonated Carbonation is the chemical reaction of carbon dioxide to give carbonates, bicarbonates, and carbonic acid. In chemistry, the term is sometimes used in place of carboxylation, which refers to the formation of carboxylic acids. In inorganic ch ...

– soft drinks that are alternatives to

bottle A bottle is a narrow-necked container made of an impermeable material (such as glass, plastic or aluminium) in various shapes and sizes that stores and transports liquids. Its mouth, at the bottling line, can be sealed with an internal stop ...

s and cans.

Premix

Premix refers to a ready-mixed,

ready-to-drink Ready to drink (often known as RTD) packaged beverages are those sold in a prepared form, ready for consumption. Examples include iced tea (prepared using tea leaves and fruit juice) and alcopops (prepared by mixing alcoholic beverages with frui ...

soft drink that has usually been packaged in 5-gallon stainless steel tanks called

Cornelius kegs A Cornelius keg (also known as a Corny keg or soda keg) is a stainless steel canister (keg) originally used as containers by the soft drink industry. They can be used to store and dispense carbonated or nitrogenated liquids. Cornelius kegs were ...

(or "Corny keg" for short). The premix itself is identical to the beverage of the same brand that is sold in bottles or cans, and is already carbonated. The soft drink is passed through a premix dispenser that refrigerates it before dispensing it through a pressure-compensating valve or tap. A premix dispenser is suitable for outlets that regularly sell the particular soft drink, but in relatively small amounts. At the plant, a quality control manager periodically checks the carbonation level of the premix tanks with a carbonation tester before shipment.

Postmix

Postmix refers to the system in which a flavored syrup (concentrate) of the soft drink is shipped to the retailer, usually in a returnable tank or a disposable

bag-in-box A bag-in-box or BiB is a container for the storage and transportation of liquids. It consists of a strong bladder (or plastic bag), usually made of several layers of metallised film or other plastics, seated inside a corrugated fiberboard box. ...

container. At the point of sale, the soft drink is mixed to order from the postmix syrup, chilled and

purified water Purified water is water that has been mechanically filtered or processed to remove impurities and make it suitable for use. Distilled water was, formerly, the most common form of purified water, but, in recent years, water is more frequently puri ...

, and

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

(from a gas cylinder), and usually dispensed from a

soda fountain A soda fountain is a device that dispenses carbonated soft drinks, called fountain drinks. They can be found in restaurants, concession stands and other locations such as convenience stores. The device combines flavored syrup or syrup concentra ...

or soda gun. A postmix dispenser is a more sophisticated device than a premix dispenser. The postmix system is suitable for outlets that serve large amounts of soft drinks quickly, such as a sports stadium or a busy fast-food restaurant.

References

* * Mixed drinks Soft drinks Cola Liquid containers Packaging {{beverage-stub