 Traditional methods of processing cassava to remove cyanogens consist of sun drying and heap fermentation in East Africa, which are inadequate in removal of cyanogens even in a year of normal rainfall.In Central Africa soaking (retting) of cassava roots in water for 4–5 days is adequate, but short soaking for 1–2 days leaves large amounts of cyanogens in flour and leads to konzo.In West Africa a roasted product called gari is produced by a different method than that used to produce flour, which reduces the total cyanide content to 10–20 ppm.