Abstract: A process is disclosed for managing or controlling fermentation product profiles in a parallel pair of beer product streams in which a brewer's wort is fermented to produce a beer having fermentation products therein. The beer is passed along a first side of a semipermeable membrane, under selective fermentation product passing conditions, to transfer selected fermentation products across the membrane, and into an unfermented beer wort on a second side of that membrane. This procedure results in the production of an unfermented wort having a permeate-supplemented fermentation product profile and a fermented wort having a permeate-reduced product profile. The unfermented wort is then itself fermented to produce a second fermented wort. The second fermented wort has a combination of fermentation-supplemented and permeate-supplemented fermentation product profiles. The respective fermented worts are then finished and-packaged for subsequent distribution and consumption.