Argon
What it does
Inert packaging gas.
How it's made
Purified from air.
Argon is an inert gas used in food packaging to displace oxygen and create a protective atmosphere, helping to preserve foods and drinks (including some wines and bottled products) by slowing oxidation and spoilage. It is completely unreactive, which is exactly why it is useful.
It is obtained from the air, which is about 1% argon. Air is cooled and compressed until it liquefies, and then slowly warmed in a fractional distillation column; because argon, nitrogen and oxygen boil at slightly different temperatures, they can be separated, and the argon fraction is drawn off and purified.
The purified argon is compressed into cylinders for use. Being chemically inert, it simply takes the place of oxygen in a package or container, providing a protective blanket without reacting with the food, which keeps flavour, colour and freshness for longer.
Possible reactions
Inert and safe.