Potato starch

Mix it with an equal amount of cold water to make a smooth slurry, then stir it into the hot sauce. Bring it just to a simmer until glossy and thick; prolonged boiling can make the texture thin again.

Yes. It gives cakes and biscuits a tender, light texture, and can replace some of the flour rather than all of it; it has no gluten to provide structure. It is also useful for coating ingredients before frying.

Yes, use it in roughly the same quantity to thicken soups, gravies and fruit fillings. Potato starch thickens quickly and gives a glossy finish, but add it near the end and avoid a long boil; cornflour tolerates simmering better.

No. Potato starch is the extracted starch, while potato flour is made from dried potatoes and contains more of the potato itself. Potato flour has 6.9 g protein and 5.9 g fibre per 100 g, compared with 0 g protein and 0.6 g fibre in potato starch.

Keep it tightly sealed in a cool, dry cupboard, away from steam and strong smells. Moisture makes it clump, so use a dry spoon and close the packet promptly.

Pure potato starch is naturally gluten-free, as it comes from potatoes rather than wheat, barley or rye. For someone who must avoid gluten, choose a packet labelled gluten-free, as manufacturing can introduce cross-contact.

Yes. Dust dry pieces of tofu, fish or vegetables lightly with potato starch before frying; it forms a delicate, crisp coating. Shake off excess starch so it does not turn gummy in the oil.

Potato starch is a fine, nearly pure thickener; potato powder is made from dried potato and is used to add potato flavour or make instant mash. Potato powder has 8.4 g protein and 7.7 g fibre per 100 g, compared with 0 g protein and 0.6 g fibre in potato starch.