Potassium Nitrite

How it's made

Synthesised nitrite salt.

Potassium nitrite is a curing salt used as a preservative in cured meats, where it prevents the growth of dangerous bacteria — most importantly the one that causes botulism — and helps fix the pink colour and characteristic flavour of cured products like some hams and sausages.

It is manufactured chemically, typically by reducing potassium nitrate, or by absorbing nitrogen oxide gases into a potassium base such as potassium hydroxide or potassium carbonate. Both routes yield potassium nitrite, which is then purified.

The salt is crystallised into a white to slightly yellow powder and, for safety, is usually supplied to meat processors pre-diluted in ordinary salt (as "curing salt") because pure nitrite is potent. Its use is tightly regulated with strict limits, because while it is essential for preventing botulism in cured meats, nitrites can form small amounts of compounds of health concern, so the minimum effective amount is used.