Stigmas and threads

A stigma spice is the tiny female part of a flower. Saffron, the dried stigmas of Crocus sativus, is the only common example and is the costliest spice by weight.

What it is

Each saffron crocus flower has three red stigmas, which must be picked by hand, usually early in the morning in autumn, then dried. It takes a very large number of flowers to make a small amount of saffron, which explains the price. Iran grows most of the world's saffron, with Spain, India and Morocco also producing it.

How it is used

Saffron gives a golden colour and a honey-like, slightly bitter scent. It is steeped in warm water or milk before use, then added to rice dishes such as paella, biryani and Persian polo, to bouillabaisse, and to sweets and breads.

Buying and keeping

Buy whole threads rather than powder, which is easier to adulterate. Good threads are deep red with a little orange at the tip, and smell strong and sweet. Store in a closed tin away from light.