Khamin (Turmeric)

Turmeric, Curcuma longa, is a rhizome native to South Asia and long established across mainland Southeast Asia, where it is grown for the kitchen and the dye pot alike. In Thai cooking, khamin (turmeric) belongs above all to the southern table, where the fresh root is pounded into curry pastes and rubbed into fish and chicken before frying. David Thompson in Thai Food places it among the defining aromatics of southern curries, and it is carried today by the home cooks and market pastemakers of the peninsula, who buy it fresh by the hand from the morning market.

The part used is the rhizome: a knobbly, finger-thick root with thin tan skin and flesh of a deep orange-yellow that stains whatever it touches. Fresh khamin is peeled, sliced across the grain into coins, and then pounded to a paste in the mortar; it is smelled before it is bought, for it should be earthy, slightly peppery and faintly bitter, with a clean resinous edge. The dried, powdered form exists but is a poor relation, flat in aroma and dull in colour, and the fresh root is what the southern kitchen means by the word.

Khamin is eaten with the foods of the south: fish, shellfish and chicken, often in coconut-based or dry-fried preparations, and always beside plain steamed rice. It is drunk against with cool water, tea or something lightly sweet, since the dishes it seasons are hot with chilli. The structural reason is that turmeric brings an earthy, faintly bitter depth that steadies the sweetness of coconut and the sharpness of chilli, and it tempers the strong smell of fish and shrimp paste, so the plate holds together rather than shouting in one register.