The beer fills the glass, tiny bubbles predominating in the pour. You can tell this is no ordinary fizz. As the bubbles dissipate, they settle toward the bottom of the glass, then cascade up toward the rim, like a frothy waterfall defying gravity.
The magical movement settles, leaving a thick white raft on top. But when you take a drink of your nitro beer, you realize the magic is still there, imparting a rich and creamy feel to every sip.
Nitro beer used to be synonymous with Guinness Dry Irish stout, and it implied something special about the beer itself. But a closer look at what makes a beer nitro shows that the process can be used with any variety of beer. Indeed, more bars are maintaining independent nitro lines and more breweries are producing beers for them, enabling the consumer to experience the decadent sensation with myriad flavors. Besides stouts, you can find nitro India pale ales, spiced and fruit beers, wheat beers and whatever other experiments brewers have tried.
The magic of the nitro pour occurs at the tap. Draft systems primarily use carbon dioxide to push the beer from keg to the spout and to maintain the carbonation level intended by the brewer. If the spout isn’t directly next to the keg, a bit of nitrogen helps push the beer through the lines.
A gas blend favoring nitrogen over carbon dioxide changes the end product. Nitrogen gas doesn’t dissolve but leaves tiny bubbles that contribute to the creaminess of the pour.
And do all styles rise to the nitro occasion? Beer fans don’t seem to think so — dark ales are preferred over others. Stouts, after all, are touted for their smoothness.
Other properties of the nitro pour also may affect fans’ perceptions. Aggressive carbon dioxide bubbles release more aromatic molecules into the air than insoluble nitrogen bubbles, so hoppy styles lose their perfumed potency when served nitrogenized. And the acidity of carbon dioxide accentuates bitter flavors. Nitrogen subdues them.
Although the brewing process needn’t change for a beer destined for a nitrogen line, the kegging process does. A beer kegged with carbon dioxide that’s run through nitro lines maintains its taste but loses carbonation quickly.
Blue Mountain Brewery in Nelson County has had Nitro Porter in the lineup since opening in 2007. “Absolutely nothing is different in the way we brew these,” owner Taylor Smack says, “but after filtration is where the differences start.”
The brewery adds less carbon dioxide than for other types of beer, kegs it and then adds nitrogen. “So yes,” he says, “these are specifically processed in this way for nitrogen lines.”
Old Bust Head Brewing Co. in Fauquier County runs carbon dioxide and nitrogenized versions of Gold Cup Russian imperial stout side-by-side at its tasting room — perfect for comparisons.
“Gold Cup on nitro pours with a much more velvety, creamy mouth feel,” Old Bust Head’s Owen Bitas says, “and some of the bolder dark malt tones become a bit more subdued, which allows for a rounded sweetness to show up in the beer.”
These days, you don’t have to leave home to try the creamy beer. Guinness was first to package it by adding a nitrogen widget to its dry Irish stout cans. Colorado’s Left Hand Brewing initiated the practice among American craft breweries in 2011 with its milk stout. Breckenridge Brewery improved upon the technology, and you can pick up its nitrogenized vanilla porter and seasonals such as chocolate orange stout from beer cases around town.
Still, Virginia-brewed packaged nitro beers are but a twinkle in the brewers’ eyes. If you want to grab a local can, you can give your liver a break and try nitro cold brew coffee from Richmond’s Confluence Coffee Co. But whichever beverage you choose, the same tiny bubbles will cascade and rise, tickling your tongue and smoothing the way for the next one. S
