The cooking process is vital to the pretreatment of some oilseeds. It consists of heating the seed and reducing the moisture content.
The cooking operation is usually carried out in a stacked cooker, a vertical design where the seed moves down through steam-heated trays, each with its own stirrer system mounted on a common vertical shaft. The diameter of the stack and number of trays depends on the capacity required and the seed being processed.
A small quantity of direct steam can be injected at the top trays to heat the seed and improve the rupturing of the oil-bearing cells. After that, the steam coming from the vaporization of the seed moisture is sufficient. The stirrers agitate the material to ensure uniform cooking and provide a means for transferring meal through successive compartments.