The cashew, Anacardium occidentale L., belongs to the Anacardiaceae or cashew family. Two related plants in this family are the mango tree and pistachio tree.
The cashew tree is native to South America where it flourishes in Brazil and Peru. In the sixteenth century, Portuguese traders introduced the tree to India where it has more recently become an important export crop equal to that of Brazil. Other countries that grow and export cashews include Sri Lanka, China, Malaysia, the Philippines, Thailand, Colombia, Guatemala, Venezuela, the West Indies, Nigeria, Mozambique, Tanzania, and Kenya. The United States is the largest importer of cashew nuts.
The cashew tree is a hearty, fast-growing evergreen with an umbrella-like canopy. Under favorable conditions it may reach a height of forty to fifty feet. The tree has a rather messy look with it's gnarled stem and crooked branches. Lower branches rest near the ground and may root, further augmenting it's spreading form. The leaves of the cashew tree are four to eight inches long and two to three inches wide. Its aromatic flower clusters are a yellowish pink.
Cashew trees produce both a fruit ("apple") and a nut, and a valuable oil can be drawn from the nut shell. After the cashew flower blooms, a nut forms. The apple later swells between the nut shell and the stem. It takes two months for the cashew apple to ripen. When harvested, the apple can only keep for twenty-four hours before it begins to ferment. Although the fruit can be used for making many typical fruit products (jellies, jams, juice, wine and liquor), the apple is often discarded, in pursuit of the nut. If processed and stored properly, the cashew nut can be kept for a year or longer. Technically, the actual nut is the thick-shelled seed. The outer shell (coat) of the seed contains the poison oak allergen urushiol, and may cause dermatitis in hypersensitive people.
There is a toxic resin inside the shell layer. If the shell is not opened properly, the resin will get on the cashew nut, making it inedible. Most companies steam the shell open at a high temperature, thus cooking the cashew nut inside. A certain nut producer in Indonesia uses a special technique with specially-designed tools (without using any heat at all) to open the shell cleanly every time without ever exposing the cashew nut to the resin. The raw cashews are much sweeter, tastier, and nutritious than their cooked counterparts.
Many people avoid cashew nuts because of their high fat content, though they are lower in total fat than almonds, peanuts, pecans, and walnuts. Cashew provide essential fatty acids, B vitamins, fiber, protein, carbohydrate potassium, iron, and zinc. Like other nuts, cashews have a small percentage of saturated fat; however, eaten in small quantities cashews are a highly nutritious food.