Process for thermally treating a product with steam

A method for thermally treating cocoa beans or cocoa nibs in order to have the cocoa beans or cocoa nibs have an improved quality, comprising the following steps:

• (a) determining a water activity value which, for carrying out the thermal treatment, is required to have the cocoa beans or cocoa nibs obtain the improved quality;
• (b) contacting the cocoa beans or cocoa nibs with water vapour comprising superheated steam and an associated saturated vapour pressure (p*), while the temperature on the surface of the cocoa beans or cocoa nibs is 80-140° C.;
• (c) setting a vapour pressure (p) in step (b) such that p/p* is equal to the water activity value determined in step (a), wherein step (c) comprises calculating a desired value for a pressure of the superheated steam according to p=aw×p* and providing the superheated steam at substantially said pressure, where aw is a water activity value;
• and (d) maintaining for a time duration (t) the process conditions mentioned in steps (b) and (c) for obtaining the cocoa beans or cocoa nibs with the improved quality, wherein the pressure of the water vapour is below 3 bar absolute and wherein the p/p* has a value of 0.4-0.8, and wherein the method is practiced in the absence of oxygen.