The use of the enzyme alpha -acetolactate decarboxylase allows the acceleration of beer fermentation/maturation because it shunts diacetyl formation, whose elimination is the rate-limiting step of the process. To obtain a cost reduction by using this exogenous enzyme, we propose a new process involving recoverable encapsulated alpha -acetolactate decarboxylase. The performance of traditional and new processes was investigated by a modeling approach. A simple model, focused on alpha -acetolactate and diacetyl profiles during beer fermentation, was set up. The simulated profiles are consistent with literature data. This study shows also that encapsulated alpha -acetolactate decarboxylase allows the acceleration of beer fermentation as efficiently as free alpha -acetolactate decarboxylase. The advantage of immobilized alpha -acetolactate decarboxylase versus free enzyme is that it is recoverable and reusable, which means a process cost reduction.