What is a Nitro Beer?

What does it mean when a beer is “on nitro”?  That’s a great question, and one that we get a lot in the taproom. 

Nitro refers to the type of gas used in the carbonation process. Instead of the normal carbon dioxide (CO2) that is used, beers are “nitrogenized” with, obviously, nitrogen (N2). Nitrogen is largely insoluble in liquid, which gives the beer a smoother and creamier mouthfeel. Most nitro beers contain about 70 percent nitrogen and 30 percent carbon dioxide.  

Nitro beers require a special piece of tap equipment called a restrictor plate which forces the beer through multiple tiny holes before it is poured into the glass. The liquid passing through the holes causes the “rising” effect that creates the head (or foam) of the beer. 

Nitrogenized beers were created and made popular by Guinness. In the late 1950s by Micahel Ash, a mathematician at Guinness, wanted to develop a pouring system that would produce the perfect pint of draught beer. The key to his pouring system was nitrogen. 

Michael Ash drinks a pint of Guinness. (Photo by Jeff Alworth/All About Beer Magazine)

The first nitro keg went through two designs before Guinness was able to use it and send it to pubs around Dublin. There was a limited release in the summer of 1959 to coincide with the brewery’s 200th anniversary. The nitro pour quickly took off and spread throughout the United Kingdom before making its way to the United States.

Michael Ash (Photo: guinness.com)

Nitrogenized beers don’t have to be draft only. A nitro pour can be accomplished both in a can and bottle. A nitrogen-filled widget is activated when the can or bottle is opened.

Left Handing Brewing was the first brewery in the United States to bottle a nitro beer. However, the Colorado-based brewery developed its own patented process and does not use a widget in bottles of their Nitro Milk Stout. Oskar Blues became the first craft brewery in the U.S. to put a nitro beer in a can, releasing Old Chub Nitro in April 2014. Left Hand debuted their famous Nitro Milk Stout in cans in July 2017. 

Maltier beers such as English, Irish and Scottish ales are usually the styles of beers you will see on nitro. However, recently breweries have been experimenting with other styles such as sours and IPAs. Over the summer, we had our Passionfruit Gose Style Ale on nitro that our customers really enjoyed.

Most people know us for the two beers we always keep on nitro; Reformation, a Scottish Stout and Yorkshire, an English Ordinary Ale. We do bottle these two beers, but they are not nitrogenized. 

Next time you’re in the taproom and haven’t had a nitrogenized beer, ask the bartender for a pint of Reformation or Yorkshire to experience a beer “on nitro”. 








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