Nitrous Oxide
What it does
Propellant (whipped cream).
How it's made
Manufactured gas.
Nitrous oxide is the gas used as a propellant in aerosol whipped cream — it is what pushes the cream out of the can and, dissolved under pressure, whips it into a foam as it leaves the nozzle. It is chosen because it dissolves well in cream fat and is not very reactive with food.
Industrially it is made by carefully heating ammonium nitrate, which decomposes to give nitrous oxide and water vapour. The reaction must be closely controlled for safety, and the gas produced is then thoroughly purified, since food and medical grades must be very clean.
The purified nitrous oxide is compressed into the cream charger or aerosol can. Under pressure it dissolves into the cream; when the valve is opened, the sudden drop in pressure lets the gas expand and foam the cream instantly. Only food-grade, highly purified gas is permitted for this use.
Possible reactions
Safe as a food propellant; misuse by inhalation is harmful.