Central Thailand is cassava country. Its an interesting crop… Bear with me.
Cassava comes from the jungles of Northern Brazil, and the plant was carried by Portuguese and Spanish explorers to the rest of the world, including Thailand, which is now the world’s largest exporter. It is the third largest source of carbohydrates in the tropics (after rice and maise).
The problem is, cassava – and especially its more bitter and resilient varieties – is laced with dangerous amounts of cyanide (up to 1 gram per kilogram). Consumption of too much can leave one severely ill, and the repeated consumption of cassava without proper treatment causes Konzo disease – an accute and incurable form of paralysis.
So why would anyone eat it? Well, prepared in the right way, it can be both safe and delicious. The word “tapioca” actually describes a process of detoxification of cassava in the Tupi language spoken by the native people of Brazil. In this process, the cassava root is first ground down to a flour. To remove the cyanide, the flour is first supersaturated for a day and let to dry in the sun for hours more. It is then wet again, and traditionally stuffed into a long woven fabric tube and hung from a tree branch while the bottom of the tube is twisted and stretched to squeeze out all the liquid. This liquid is collected and let to dry in the sun once more until only the powdery residue – the tapioca – remains.
It is grown in this dry, central Thailand area because it is one of the most drought tolerant crops capable of growing any time of year on even marginal soils. Because it takes so long to prepare and can be harvested at any time, in many countries it is a food of reserve and last resort, consumed in times of food insecurity. The name of the plant Ewe language of West Africa – “agbeli” – literally means “there is life”. But in times of the most severe famine, the detoxification of cassava is skipped, and Konzo outbreaks ensue.
The Chinese love tapioca, and is the main buyer of Thailand’s tapioca. Although its almost pure starch and contains negligible amounts of protein and nutrients, it is used in a lot of industrial cooking as a thickener and binding agent, to improve textures creating a gel-like texture that traps moisture. Its also great in puddings, and as pearls in bubble tea.