A fountain drink is a soft drink

Soft drink

A soft drink is a non-alcoholic beverage that typically contains water , a sweetener, and a flavoring agent...

, prepared locally from a supply of flavor

Flavor

Flavor or flavour is the sensory impression of a food or other substance, and is determined mainly by the chemical senses of taste and smell. The "trigeminal senses", which detect chemical irritants in the mouth and throat as well as temperature and texture, are also very important to the overall...

ed sweetened

Sweetener

Sweetener is a sugar substitute.Sweetener may also refer to:* Sugar alcohol* Honey* Syrup...

 syrup

Syrup

In cooking, a syrup is a thick, viscous liquid consisting primarily of a solution of sugar in water, containing a large amount of dissolved sugars but showing little tendency to deposit crystals...

, carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

, and water

Water

Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...

, either manually, in a device called a 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...

, or in a vending machine

Vending machine

A vending machine is a machine which dispenses items such as snacks, beverages, alcohol, cigarettes, lottery tickets, consumer products and even gold and gems to customers automatically, after the customer inserts currency or credit into the machine....

 which is essentially an automated soda fountain that is operated using a soda gun

Soda gun

A soda gun or Bar gun is a device used by bars to serve various types of carbonated and non-carbonated drinks. A soda gun has the ability to serve any beverage that is some combination of syrup, water and carbon dioxide. This includes soft drinks, iced tea, carbonated water, and plain water...

. Today, the syrup often is pumped from a special container called a Bag-In-Box

Bag-In-Box

In packaging, a bag-in-box or BiB is a type of container for the storage and transportation of liquids. It consists of a strong bladder , usually made of several layers of metallised film or other plastics, seated inside a corrugated fiberboard box. The bag is supplied to the 'filler' as an empty...

(BIB).

Also referred to as a post mix machine in some markets.