Homogenizers may be equipped with one homogenising device or two connected in series, hence the names single-stage homogenization and two stage homogenization.
In both single-stage homogenization and two-stage homogenization, the whole homogenization pressure (P1) is used over the first device. In singlestage homogenization, the back pressure (P2) is created by the process. In two-stage homogenization the back pressure (P2) is created by the second stage. In this case the back pressure can be chosen to achieve optimal homogenization efficiency. Using modern devices, the best results areobtained when the relation P2/P1 is about 0.2. The second stage also reduces noise and vibrations in the outlet pipe (Bylund, 2003).
Single-stage homogenization may be used for homogenization of products with high fat content demanding a high viscosity (certain cluster formation).
Two-stage homogenization is used primarily to reach optimal homogenization results and to break up fat clusters in products with a high fat content.