The rhizome of a ginger relative from South Asia, used fresh or dried and ground for its earthy, bitter warmth and brilliant yellow colour. India grows the great majority of the world's crop.
What it is¶
Turmeric is the underground stem, or rhizome, of Curcuma longa, a leafy perennial in the ginger family that grows to about a metre. The rhizomes branch into "fingers" with tough brown skin and vivid orange flesh.
To make the familiar powder, the rhizomes are boiled or steamed, dried until hard, polished and ground. Boiling sets the colour and cooks out the raw starch. The yellow pigment is curcumin and related curcuminoids, which make up a few per cent of the dried spice. Turmeric is also one of the most widely used natural food colourings (E100).
Origins and history¶
Turmeric has been used in South Asia for thousands of years, as food, dye, medicine and in religious and social ritual. The cultivated plant is a sterile hybrid that does not set seed; it is propagated from pieces of rhizome, and its wild ancestry is uncertain. Its Sanskrit names include haridra, and in Hindi it is haldi. The haldi ceremony, in which the bride and groom are anointed with turmeric paste before a Hindu wedding, is one of many ritual uses.
It spread early through Southeast Asia and to China, and reached the Mediterranean via Arab traders. Medieval Europeans called it "Indian saffron", and Marco Polo's account of a Chinese plant with the colour and smell of saffron is usually taken to describe turmeric. Its cheapness and colour made it both a staple and, from early on, a saffron substitute.
Flavour and aroma¶
Ground turmeric is earthy, musky and faintly bitter, with a mild peppery warmth; its flavour is more of a foundation than a highlight. Raw powder tastes chalky, so it should always be cooked, usually briefly in fat. Fresh turmeric is juicier, brighter and more gingery, with a citrus-carrot note, and is used much like fresh ginger. Too much ground turmeric makes a dish bitter and medicinal.
In the kitchen¶
- Indian cooking. A near-universal base spice in dals, curries, vegetable dishes and rice. Typical quantities are ½–1 tsp ground turmeric for a dish serving four, added to hot oil with the onions or other ground spices and fried for 30 seconds. See indian-cuisine and blooming-spices-in-oil.
- Spice mixes. A main ingredient in curry powder and in some versions of ras-el-hanout and hawaij.
- Southeast Asia. Fresh turmeric is pounded into Indonesian, Malaysian and Thai curry pastes, nasi kuning (yellow rice) and kunyit marinades, and the leaves are used to wrap fish for grilling. See indonesian-and-malaysian-cuisine.
- The Middle East and North Africa. In Persian stews and rice, Moroccan tagines and Levantine sfouf cake.
- Pickles and mustard. British piccalilli and American yellow mustard owe their colour to turmeric.
- Drinks. Haldi doodh, warm milk with turmeric, is a traditional Indian drink.
⚠️ It stains
Turmeric stains worktops, wooden spoons, plastic and fingers bright yellow. Clean spills quickly; sunlight helps fade stains on fabric and plastic.
Buying and storing¶
Ground turmeric keeps better than most ground spices, but still fades after about a year; store it airtight, away from light, which bleaches curcumin. Fresh rhizomes keep for two to three weeks in the fridge, wrapped in paper inside a bag, and freeze well whole; grate from frozen. Look for firm, heavy fingers with no soft spots.
Varieties are traded by region: Alleppey (Kerala) and Lakadong (Meghalaya) are known for high curcumin content and deep colour; Erode and Madras turmeric are lighter and brighter.
Substitutes¶
Nothing replaces turmeric's flavour. For colour alone, a pinch of saffron (more expensive and differently flavoured) or annatto will do. Swap fresh and ground at roughly 1 tbsp grated fresh for 1 tsp ground.
Pairs well with¶
cumin, coriander seed, ginger, garlic, black pepper, mustard seed, fenugreek, chilli, galangal, lemongrass, coconut milk, lentils, rice, cauliflower, potatoes, eggs, fish, chicken.
Growing your own¶
Turmeric can be grown from supermarket fresh rhizomes. Choose plump pieces with visible buds, and plant them 5 cm deep in a wide pot of free-draining compost in late winter or early spring. It needs warmth, ideally 20–30 °C: a sunny windowsill, conservatory or heated greenhouse in cool climates. Keep the compost moist but not waterlogged, and feed through summer.
It takes 8–10 months. When the leaves yellow and die back in autumn, tip out the pot and harvest the rhizomes, saving a few pieces to replant. Plants make handsome foliage, and in warm conditions can flower. See growing-your-own-spices.
Health and safety¶
⚠️ Lead chromate adulteration
Turmeric has repeatedly been found adulterated with lead chromate, an industrial yellow pigment, to brighten the colour of poor-quality rhizomes. Research in Bangladesh linked it to elevated lead levels in people, and it has prompted product recalls elsewhere. Buy from reputable brands, and be wary of unusually bright, cheap loose turmeric. See lead-in-spices and spice-adulteration.
Culinary amounts of turmeric are considered safe. Concentrated turmeric and curcumin supplements are a different matter: there have been reports of liver injury associated with them, and they can interact with some medicines, including anticoagulants. Health claims made for curcumin supplements go well beyond what the evidence supports; see curcumin.