Cornstarch: Cornstarch is a fine white starch from corn. It thickens sauces and soups, gives a crisp coating to fried foods and softens the texture of cookies and cakes.
How it is used
To thicken, mix cornstarch with a little cold water into a slurry, stir it into a simmering liquid and cook for a minute or two until clear and glossy. Never add it dry to hot liquid, which makes lumps. In stir-fries a light cornstarch coating protects meat and creates the silky texture known in Chinese cooking as velveting. In baking it is mixed with flour for tender cakes and shortbread. It is gluten-free, but check the label for cross-contamination if you need to avoid gluten.
Background
Corn is native to the Americas; industrial cornstarch production began in the 1800s.
Buying and storing
Store in a dry airtight container. It keeps for a long time.
Good to know
Potato starch, arrowroot or tapioca starch can often replace it, though they behave slightly differently. Starch-thickened sauces can thin if boiled for a long time.