Cashew nuts grow on cashew nuts (Anacardium occidentale). As such, they are classified as a type of tree nut. Although it is a true nut, rather than a legume, the cashew tree grows in a rather unusual way. The tree produces a substantial crop of large, pear-shaped fruits known as cashew nuts, and the nut itself grows from the underside of the fruit into a cashew-shaped shell.
The fruit is tasty and nutritious, and the tree is often grown just for it. It can be eaten like an apple, cooked as a vegetable, dried, made into jams and syrups, or even fermented to produce alcohol. Strangely enough, from a botanical point of view, the nut and its shell are the true fruit of the tree. The cashew nut is just a strangely swollen seed stalk, despite its tasty pulp.
Cashew nuts aren't really nuts in the true sense, but rather a drupe seed. They grow on fruit trees that produce a “false fruit” known as a cashew tree. The fruit resembles a small yellow to red pepper. At the base of the fruit there is a hard shell in the shape of a bean with a single seed inside: the cashew nut.
Is cashew a vegetable or a nut? Technically, it's not. Instead, it's a thick-shelled seed with an interesting story. The cashew tree is a member of the evergreen tree family that produces an edible pear-shaped fruit known as a cashew. Finally, the walnuts are extracted from their shells and the inner shell, or testa, is removed to leave only the edible nut.
The cashew tree is large and evergreen, growing to 14 meters (46 feet) tall, with a short trunk, often irregularly shaped. In the Indian state of Goa, ripe cashew nuts are crushed and the juice is extracted and preserved for fermentation for a few days, which is called Neero. The cashew nut yields of the traditional tree are about 0.25 metric tons per hectare, in contrast to more than one ton per hectare of the dwarf variety. Liquid cashew shell oil (CNSL) or cashew shell oil (CAS registration number 8007-24) is a natural resin with a yellowish sheen found in the honeycomb structure of the cashew shell and is a by-product of cashew nut processing.
Although some determined hobbyists roast their own nuts for home consumption, it is a difficult and dangerous task that is best left to professionals. Discarded cashew nuts not fit for human consumption, along with oil extraction waste from cashew nuts, can be used to feed livestock. You may be allergic to peanuts or nuts without being allergic to the other, or you may be allergic to both. Cashew nuts are commonly used in South Asian cuisine, whole to garnish candies or curries, or ground into a paste that forms a base of sauces for curry (e.g., the most common method for opening shells is to steam them, but high temperatures cook the nut inside).
The culinary uses of cashew seeds for chopping and cooking are similar to those of all tree seeds called walnuts. The most recent breeds, such as dwarf cashew trees, are up to 6 m tall and start producing after the first year, with economic returns after three years. Enjoying cashew is easy, but preparing the nut itself is a surprisingly difficult and dangerous task. A woman uses a cashew nut peeling machine in Thailand and wears gloves to protect against contact dermatitis.