Candlenuts, similar in shape to hazelnuts, are small, white, waxy nuts-called buah keras in Malaysia and Indonesia-used primarily as a thickening agent for spice pastes. Blanched almonds or unsalted macadamia or Brazil nuts may be substituted. Candlenuts are available in Indian and Asian markets. For other nut varieties, see almonds, Brazil nuts, cashews, chestnuts, hazelnuts, macadamia nuts, peanuts, pecans, pine nuts, pistachios, and walnuts.
Aleurites moluccana, the Candlenut, is a flowering tree in the spurge family, Euphorbiaceae, also known as Candleberry, Indian walnut, Kemiri, Varnish tree, Nuez de la India, Buah keras or Kukui nut tree.
Its native range is impossible to establish precisely because of early spread by humans, and the tree is now distributed throughout the New and Old World tropics. It grows to a height of 15–25 m (49–82 feet), with wide spreading or pendulous branches. The leaves are pale green, simple and ovate, or trilobed or rarely five-lobed, with an acute apex, 10–20 cm (3.9–7.9 inches) long. The nut is round, 4–6 cm (1.6–2.4 inches) in diameter; the seed inside has a very hard seed coat and a high oil content, which allows its use as a candle (see below), hence its name.
The nut is often used cooked in Indonesian and Malaysian cuisine, where it is called kemiri in Indonesian or buah keras in Malay. On the island of Java in Indonesia, it is used to make a thick sauce that is eaten with vegetables and rice. In the Philippines, the fruit and tree are traditionally known as Lumbang after which Lumban, a lakeshore town in Laguna is named although the name Jatropha has since gained more popularity. Outside of Southeast Asia, macadamia seeds are sometimes substituted for candlenuts when they are not available, as they have a similarly high oil content and texture when pounded. The flavor, however, is quite different, as the candlenut is much more bitter. At least one cultivar in Costa Rica has no bitterness, and an improvement program could likely produce an important food crop if non-toxic varieties can be selected and propagated. A Hawaiian condiment known as ʻInamona is made from roasted kukui (candlenuts) mixed into a paste with salt. ʻInamona is a key ingredient in traditional Hawaiian poke.
Several parts of the plant have been used in traditional medicine in most of the areas where it is native. Candlenut oil is sometimes used like castor oil. In Japan its bark has been used on tumors. In Sumatra, pounded seeds, burned with charcoal, are applied around the navel for costiveness. In Malaya, the pulped kernels or boiled leaves are used in poultices for headache, fevers, ulcers, swollen joints, and gonorrhea. In Java, the bark is used for bloody diarrhea or dysentery. In Hawaiʻi, the flowers and the sap at the top of the husk (when just removed from the branch) were used to treat eʻa (oral candidiasis) in children.
In ancient Hawaiʻi, kukui nuts were burned to provide light. The nuts were strung in a row on a palm leaf midrib, lit one end, and burned one by one every 15 minutes or so. This led to their use as a measure of time. One could instruct someone to return home before the second nut burned out. Hawaiians also extracted the oil from the nut and burned it in a stone oil lamp called a kukui hele po (light, darkness goes) with a wick made of kapa cloth.
Hawaiians also had many other uses for the tree, including: leis from the shells, leaves and flowers; ink for tattoos from charred nuts; a varnish with the oil; and fishermen would chew the nuts and spit them on the water to break the surface tension and remove reflections, giving them greater underwater visibility. A red-brown dye made from the inner bark was used on kapa and aho (Touchardia latifolia cordage). A coating of kukui oil helped preserve ʻupena (fishing nets). The nohona waʻa (seats), pale (gunwales) of waʻa (outrigger canoes) were made from the wood. The trunk was sometimes used to make smaller canoes used for fishing. Kukui was named the state tree of Hawaii on 1 May 1959 due to its multitude of uses. It also represents the island of Molokaʻi, whose symbolic color is the silvery green of the kukui leaf.
In Tonga, even today, ripe nuts, named tuitui are pounded into a paste, tukilamulamu, and used as soap or shampoo. As recently as 1993, candlenuts were chewed into sweet-scented emollient utilized during a traditional funerary ritual in the outlying islands of the Kingdom of Tonga. Their scent was also used for making various sweet smelling oils for the skin.
Dead wood of candlenut is eaten by a larva of a coleoptera called Agrionome fairmairei. This larva is eaten by some people.
Modern cultivation is mostly for the oil. In plantations, each tree will produce 30–80 kg (66–180 pounds) of nuts, and the nuts yield 15 to 20% of their weight in oil. Most of the oil is used locally rather than figuring in international trade.