Michael Edward Ash’s Nitrogen System Creates Guinness Draught

In 1959, Guinness launched Guinness Draught, the world’s first commercially released nitrogenated beer, during the brewery’s bicentennial year. The system emerged from Guinness’s attempt to replace the traditional and labor-intensive pub practice of blending highly conditioned stout with older, nearly still beer from separate “high” and “low” casks. As beer served from sealed kegs became increasingly important, Guinness needed a method that could reproduce the smooth character and stable head of draught stout while being easier and more consistent for publicans to serve. Mathematician Michael Edward Ash had joined Guinness in 1951 and subsequently trained as a brewer. Leading the experimental project later known as “Easy Serve,” Ash and his team developed a system that dispensed stout under pressure using a mixture of nitrogen and carbon dioxide. Because nitrogen is much less soluble in beer than carbon dioxide, the beer could be held under sufficient pressure without becoming excessively fizzy. When forced through fine holes in the tap, it formed very small bubbles, creating the dense creamy head and characteristic surge-and-settle effect. The innovation transformed the presentation and sensory character of Irish stout and established a dispense method later adopted by other breweries. The widget that reproduced a related nitrogenated effect in cans was a separate Guinness innovation introduced in 1988.