This full flow, channel condition begins in the kneading zone. The flow channel fills, first, with loose granular material which is compressed and worked by shear as it passes through the kneading zone, steam at pressure of 5 and 10 atmosphere (73 and 147 psia) is sometimes injected into this zone of the extruder barrel. This steam carries with it thermal energy as well as moisture. It is in the kneading zone where the discrete particles of material begin to agglomerate because of their temperature increase resulting from conduction, direct steam injection, and viscous energy dissipation. Here, the discrete particles begin to from a more integral flowing dough mass. At the discharge end of the kneading zone, the extrudate most typically reaches its maximum compaction. The shear in this area of the extruder barrel is moderate and the extrudate temperature begins to increase.