Cashews are a popular ingredient in many dishes and snacks. These familiar nuts grow on trees, but their development differs from most other tree nuts. Their journey from tree to edible nut involves a unique fruiting process. This article explores how cashews grow, from their unusual fruit structure to the essential processing steps required for safe consumption.
The Cashew Tree and Its Unique Growth
The cashew tree (Anacardium occidentale) is a tropical evergreen tree native to northeastern Brazil. It can reach heights of up to 14 meters, though cultivated dwarf varieties grow to about 6 meters for easier harvesting. Its canopy is broad and spreading, with leathery leaves.
The cashew’s growth is distinctive because its fruit consists of two parts. A fleshy, pear-shaped or oval structure, often yellow or red when ripe, develops first; this is the cashew apple. The true fruit, containing the edible cashew nut, is a kidney-shaped drupe that dangles from the bottom of the cashew apple. This botanical arrangement means the cashew nut is technically a seed, not a true nut.
The Cashew Nut: A Hidden Gem
The cashew nut, encased in its hard outer shell, cannot be eaten directly from the tree due to a toxic, irritating oil. This oil, urushiol, is chemically related to the irritant found in poison ivy and poison oak. Direct contact with the raw shell or its oil can cause an itchy, inflamed skin rash and severe irritation. For this reason, cashews are never sold in their shells.
To make the nut safe for consumption, processing is necessary. This involves heat treatment, such as roasting or steaming, which destroys the urushiol in the shell. After this treatment, the nuts are shelled by specialized machines or skilled manual labor to extract the kernel. The kernels then undergo further drying and peeling to remove a thin, papery skin, ensuring the final product is clean and ready for packaging.
Where Cashews Thrive and Their Role
Cashew trees flourish in warm, tropical climates, specifically between 25°N and 25°S latitudes. They thrive in regions with a distinct dry season and well-drained, sandy soils. Major cashew-producing countries include Ivory Coast, India, Vietnam, and Brazil, along with other nations in Africa and Southeast Asia.
The cultivation and processing of cashews hold economic importance globally. Cashews are a valuable commodity that supports many communities in these tropical regions. The industry provides employment opportunities, particularly in processing, and generates foreign exchange through exports, supporting local economies.