Today in 1975, US Patent 3870810 A was issued, an invention of Anthony Martin Humphrey, for his “Inhibiting Beer Gushing.” Here’s the Abstract:

The present invention provides a method for reducing the tendency of beer to gush by incorporating in the beer 1 to 20 percent based on the weight of iso- alpha -acids in the finished beer of an unsaturated fatty acid having from 10 to 20 carbon atoms. The invention includes hop extracts containing said unsaturated fatty acid and also includes methods of making said extracts.