The growing trend of craft beer in recent years has resulted in thousands of micro-breweries popping up all over the country, giving beer lovers a plethora of options for any kind of taste, type, and style preference. According to the 2017 Brewer Association's annual Craft Beer in Review report, 83 percent of Americans of drinking age live within ten miles of a brewery, which means the vast majority of us have the opportunity to embrace a craft beer instead of always picking up a six-pack from a major brewery at your local gas station or grocery store.
Many brewpubs and craft breweries --- like Sierra Nevada Brewery Co., Sly Fox Beer, Sixpoint Brewery, and Yards Brewing Company --- are starting to add nitro beer to their lineup, but many of us don't know what the means or what difference it makes to the beer because it is so uncommon.
When carbonating beer, brewers have two options, either carbon dioxide (CO2) or nitrogen (N2). Just about every bar and brewery in the United States carbonate their beer (on tap and in bottles/cans) with CO2, and that is what provides bubbles, head, and releases aroma.
What makes a nitro beer different is that it has a carbonation mix of 70 percent nitrogen and 30 percent carbon dioxide (known as "beer gas"), and the use of nitrogen causes a unique reaction that gives the body of nitro beer a unique, creamy texture. For decades, most beer drinkers associated nitro with Guinness since it was the only nitrogen carbonated beer available in many areas, and it was the brewery that pioneered the technology to brew beer in this way. Guinness preferred brewing with nitrogen after the introduction of metal kegs because of its lack of odor and color.
However, with the rise of craft beer, many bars have added nitro taps in an attempt to match or exceed the traditional Guinness experience. Most craft brewery taprooms or beer bars are now dedicating at least one tap to nitrogen, but the style you find at each location will vary.
According to Beer Connoisseur, when you mix nitrogen with carbon dioxide, it keeps the beer from going flat. And, when pouring it through a tap, it first goes through a "restrictor plate" --- a perforated disk that agitates the nitrogen --- that produces the well-known froth.
It is important to note, however, that there is not a difference in a classic CO2 beer's ingredients as opposed to the Nitro version. The difference comes with aroma and mouthfeel.
Nitrogen produces a smooth, creamy beer with tiny bubbles because it doesn't dissolve as easily as carbon dioxide. Many people also find the taste to be less bitter because it accentuates the malt flavors, and because nitrogen is largely insoluble in liquid, it gives beer a much fuller feel as opposed to beer carbonated with carbon dioxide.
Many beer drinkers will notice that beer served on a nitro tap tend to be malt heavy instead of hop forward. "Historically, with grains the nitrogen just plays better," says Thomas Vincent, the pub brewer at Natty Greene's Pub and Brewery in Raleigh, North Carolina told CraftBeer.com.
Because of this, most bars using a nitro tap will stick with maltier beers because of the faded hops, but because of all of the experimentation going on with craft beer, Vincent says "anything is possible."
A nitro beer also has a different appearance when poured because of the cascading, which is where the nitrogen bubbles look like they are moving down the beer on the outside, while the bubbles in the middle move up. The cascading creates a thick, full head that looks like your beer has a whipped topping.
While nitrogen does change a beer's texture, taste, and appearance, it is worth noting that nitrogen does not alter the percentage of alcohol (Alcohol by Volume or ABV) in your beer.
You will usually find a dark ale on the nitro tap because, like Guinness, the flavors of dark beer pair well and are amplified with the creamier, thicker texture. So, you will usually see a milk or oatmeal stout, or an IPA, English Mild or Porter on the nitrogen tap.
However, if you are looking for a lager, it could be rather difficult. Craft Beer Joe says he has not seen a lager on a nitrogen tap, but that doesn't mean no one has done it.
One of the most popular brands of nitro (besides Guinness) is Left Hand. This craft beer brand offers a nitro series that includes Milk Stout Nitro, Sawtooth Nitro, and Wake Up Dead Nitro.
After the success of their draft style in the 40's and 50's, Guinness wanted to find a way for their customers to bring their beer home, but their researchers struggled to figure out a way to bottle their nitrogen beer. Bottling a beer with nitrogen was impossible because you can't produce it naturally, and must instead force it into the beer.
But, they made a breakthrough when they created the "widget," which is a small, hollow piece of plastic that has a tiny hole. Guinness was able to insert the widget into a can with a small amount of liquid nitrogen before quickly sealing it. Then, the nitrogen vaporizes and expands, which forces a small amount of beer and air into the widget and dissolves the rest of the nitrogen. When you open the can or bottle, it rapidly releases the pressure --- plus the air and beer in the widget --- and as the gas surges upward, it creates a foamy head.
Other companies have also used a widget for nitro beer in a can or bottle, but in 2011 Left Hand changed the game with their Milk Stout Nitro in a bottle, making them the first American craft brewery to "master the science of bottling" a nitrogen beer without a widget.
And, in 2017, the company also made the first-ever U.S.-made nitro widget can, giving American customers more nitro options to take home.
With nitro beer on the market more than ever before, there is a lot for customers to get excited about. So, the next time you visit your local tap room, don't be afraid to give their nitro brew a try.