The columns are made of stainless steel.  Conical vanes are attached alternately to the wall of the column and to a central rotating shaft.  The product is poured in at the top under vacuum, and steam is pumped into the column from below. The vanes provide a large surface area over which volatile compounds can evaporate into the steam, and the rotation ensures a thin layer of the product is constantly moved over the moving cone.  It typically takes 20 seconds for the liquid to move through the column, and industrial columns might process . The temperature and pressure can be adjusted depending on the compounds targeted.