Today in 1994, US Patent 5291004 A was issued, an invention of Michael S. Frank and R. Patrick Garrett, for their “Card-Controlled Beverage Distribution System.” Here’s the Abstract:

A self-service beverage distribution system includes a piping network with refrigerated tubing for transporting beverages, such as beer, from at least one source to at least one output. A drinker purchases a magnetic card which represents a predetermined quantity of beer, and which specifies which beer sources the drinker can have access to. A flow meter measures how much beer the drinker dispenses, and the quantity of beer represented on the card is decreased accordingly.