Systems and methods for controlling attenuation in a fermentation process

A method of controlling attenuation in a fermentation process comprising:

• culturing a fungus in a medium to produce beer, wherein the fungus is at least one of Saccharomyces, Dekkera, Brettanomyce, Candida, or Aspergillus;
• adding a killer toxin to the beer, wherein the killer toxin is added in an amount effective to deactivate the fungus;
• conducting a first screening assay on the beer before adding the killer toxin;
• and
• conducting a second screening assay on the beer after adding the killer toxin.