The original cashews were bred in north-eastern Brazil, from where they were imported to Mozambique and the coast of India by Portuguese sailors during the 16th century. From India, cashews spread throughout Southeast Asia until they finally reached far Africa. When we talk about breeding cashews, they are actually growing on trees of Anacardium occidentale (the cashew tree). The tree is currently grown on plantations in tropical areas. It is doing well in parts of India, Brazil, Nigeria, Vietnam, Ivory Coast, Tanzania and Indonesia. The name ‘cashew’ comes from the Portuguese word ‘caju’, literally meaning ‘nut that produces itself’.

Drupe is found at the end of the cashew apple, which is the fruit of Anacardium occidentale tree. The tree can grow up to a height of 12 meters. Cashew grows directly on the apple tree and the pseudo-fruit in the shape of an apple grows up later. The vitamin C-rich apple itself has an acidic taste, so its consumption is more rare than normal. In some parts of the world, however, cashew apples are considered real delicacies, several medicinal properties are attributed to them and are eaten to combat various bacteria. This happens, for example, in Africa or Brazil. In the cashew nut shells there is phenolic resin and irritating salicylic acid, which behaves aggressively in contact with the skin. Shells are used, for example, for the production of wood varnishes.

Traditionally, extraction of the kernel from the shell of the cashew nut has been a manual operation. The nut is roasted which makes the shell brittle and loosens the kernel from the inside of the shell. By soaking the nuts in water, the moisture content of the kernel is raised, reducing the risk of it being scorched during roasting and making it more flexible so it is less likely to crack. The CNSL is released when the nuts are roasted. Its value makes collection in sufficient quantities economically advantageous. However, for very small-scale processors, this stage is unlikely to take place due to the high cost of the special roasting equipment required for the CNSL collection (see the section on ‘hot oil’ roasting). If the nuts are being manually shelled, gloves need to be used or alternatively, the nuts should be tumbled in sawdust or ashes to absorb the liquid coating which has a harmful affect on the skin.