How soda is made

Soda is about one part flavored syrup to five parts water that has been pumped full of carbon dioxide.

stations: 5
things upstream: 76
raw sources: 22
steps from the ground: 9

The short version

Soda is made by dissolving carbon dioxide into cold water under pressure, then mixing it with a flavored syrup at about five parts water to one part syrup. The syrup carries sweetener, acid, color and flavor oils. The fizzy drink is sealed into bottles or cans before the gas can escape.

Mix the syrup

Syrup is built from a sweetener such as sugar or high-fructose corn syrup, food coloring, an acid and flavor oils. Colas use phosphoric acid, and fruit sodas use citric acid.

Goes in
Sugar Corn syrup Phosphoric acid Caramel color Water
Dissolve gas in water

Carbon dioxide is injected into water under high pressure. The gas is only weakly soluble, so pressure forces it in and it stays dissolved until the pressure is released. Food-grade carbon dioxide often comes from ammonia plants.

Goes in
Carbon dioxide Water
Blend syrup and fizz

Syrup and carbonated water are combined at a ratio of about one to five. Colas and ginger ale are carbonated to about 3.5 volumes of gas per volume of liquid, while fruity drinks get less.

1 part syrup to 5 parts water
Fill and seal fast

The drink goes into glass, plastic or aluminum containers that can take the pressure of the gas. The seal has to be tight, since a poor one lets the bubbles out and a weak bottle can burst.

Goes in
Aluminum can Plastic bottle Glass bottle
Box and ship

Cans and bottles are grouped into cardboard cartons or trays, a packaging style that took off in the 1920s.

Goes in
Cardboard

End of the lineSoda

Worth repeating

Joseph Priestley invented carbonated water in 1767 by hanging a bowl of water above a beer vat at a Leeds brewery.
Before the crown cork seal was patented in 1892, bottle makers struggled to keep the bubbles in.
J. J. Schweppe started selling bottled carbonated water in 1783.