Candlenut

The candlenut tree is a fast-growing evergreen to about twenty metres, with large pale-green, maple-like leaves that look silvery from a distance. Its round fruits hold one or two hard-shelled seeds, each about the size of a walnut. The kernel inside is creamy white, waxy and very rich in oil, with a mild flavour reminiscent of macadamia when cooked.

Candlenuts are sold shelled in small packs in Asian groceries, either raw or lightly roasted, and as a ground paste. Hawaiian kukui nuts are also polished and strung into leis. The nut's oil content is so high that a dry kernel will burn like a candle if lit, which gave the tree its English name.

The candlenut tree is native to the Indo-Malayan region and is thought to have originated in Southeast Asia, from where it was carried across the Pacific by early Austronesian voyagers as a canoe plant. It now grows throughout the tropics.

The English name refers to the old practice of stringing the oily kernels on a stick and burning them as torches. The Indonesian and Malay names kemiri and buah keras, meaning hard fruit, describe the shell. The Hawaiian kukui means light or lamp, reflecting the same use. The botanical species name moluccanus points to the Moluccas, the Indonesian spice islands.

Candlenut has been valued for thousands of years across the tropics from India to Polynesia. In the Pacific it travelled with settlers who treated it as a multipurpose tree: nuts for light and food, oil for waterproofing canoes and finishing wood, bark for dye, and leaves for medicine. In Hawaii the tree, called kukui, is the state tree and is tied to Hawaiian culture, from the lei of polished nuts to the ceremonial use of kukui oil.

In Indonesia, Malaysia and Singapore, ground candlenut became a standard ingredient in rempah spice pastes, the foundation of dishes such as rendang, opor and laksa. Cooks use it where Western cooks might use cream or ground almonds: to thicken sauces and add body. Macadamia is the usual substitute outside the region.

The oil has long been used in lamps, soaps, paints and varnish, and its popularity in modern skincare has grown. Because the seeds contain compounds that irritate the gut, traditional cooks always roast or pound and fry them before use.

Candlenuts are always cooked before eating. In Indonesian and Malaysian cooking they are pounded with shallots, garlic, chillies and turmeric into a paste, then fried, to thicken and enrich curries, soups and sambals. In Hawaii, roasted and salted kukui kernels are mashed into inamona, a relish served with raw fish such as poke.

The oil is pressed for lighting, wood finishing, soap and cosmetics, and is used in hair and skin care products. Polished shells are made into jewellery, and in traditional medicine the oil, bark and leaves have been used for skin complaints and as a laxative. Macadamia nuts are the closest culinary substitute.

There is little reliable clinical research on candlenut as a food. The kernel is very high in fat, including unsaturated fats, and contributes energy, some protein and minerals when eaten in the small amounts used in cooking.

Traditional medicine in Southeast Asia and the Pacific used candlenut oil and extracts for hair, skin and digestive complaints, but these uses are not backed by strong trials. As a cooking ingredient in modest quantities, properly cooked candlenut is safe, though there is no evidence that it prevents or treats disease.