Nitrogen Use In The Brewery: The Pour Says It All

By: Gerald Dlubala

You only have to look at the rotating list of available craft beer flavor profiles and styles at your local brew pub to know that Brewmasters are always looking for ways to please their patrons. Adding the use of nitrogen within the craft brewing industry is one of those ways that breweries look to produce a better final product for both their loyal consumers and for the distributors as well.

Nitrogen use is gaining popularity in craft breweries because it can be used as a safeguard against harmful oxygenation of their product that can affect taste, aroma and quality, all the things craft beer enthusiasts really care about. But nitrogen is also used to pressurize the containers and extend the shelf life of packaged beer. When used in conjunction with widgets or nitrogen dosing machinery before capping, it’s also responsible for that unique, cascading pour and velvety mouthfeel that signifies a nitro beer.

“Since the eighties, our liquid nitrogen dosing equipment line has expanded and improved to meet certain needs amongst the brewing industry,” says Jackie Whitney, Technical Support and Application Engineer for Vacuum Barrier Corporation in Woburn, MA, a manufacturer of nitrogen dosing equipment for use in craft breweries. “Nitrogen is used to purge the oxygen of the empty container before filling, but also to purge the oxygen from the headspace of filled containers. Nitrogen is used to pressurize cans of lower carbonated products, helping with packaging stability. And of course, it’s used for nitrogenating beers.”

“Nitrogen can be used before filling or after filling and before capping and seaming. We have our Linerter doser, used to purge empty containers before filling. It doses in a larger quantity to ensure that enough liquid nitrogen is put into the container to completely purge the oxygen out from it, similar to how it’s done for wine bottles. Our other styles of dosers are more precise, limited by line speed and size, and able to dose in smaller and more precise liquid nitrogen drops into filled containers, reducing oxygen in the headspace while pressurizing the container.”

“For small scale breweries,” says Whitney, “Liquid nitrogen is accessible in rented portable Dewars that are generally available locally from gas distributors. For the larger scale breweries requiring greater amounts, it’s generally recommended that the liquid nitrogen be stored in a refillable bulk tank located outside. Depending on the magnitude of the brewery, liquid nitrogen can be efficiently transferred from the supply tank to the doser using a vacuum insulated piping system.”

Whitney says there are no other alternatives to nitrogen. “It is the most economically feasible, inert, cryogenic gas available. It helps extend shelf life while preserving flavor and pressurizing the containers, allowing them to more easily be stacked during packaging and transportation.”

But no use of nitrogen may be more noticeable to the dedicated craft beer drinker than the characteristics it brings to that silky-smooth end product coming out of that tapper.

Whitney says that many brewers are using nitrogen infused beer to create an alternate taste for beer lovers, and because this is a relatively new craft brewing method, they are experimenting with all different kinds of nitrogen-infused beer.

“By dosing with nitrogen, breweries transform their beer into nitro beer, meaning one that has and retains a smooth, creamy head after pouring, either with or without the widget. This benefit would seem to translate across all beer styles should the brewer want to do that. The receiver of a nitro beer will notice a taste and aroma that is much fresher than that of their normal, standard carbonated beer. Nitrogenated beers have an appealing, more attractive cascade upon pouring compared to standard or regular beers, and the nitro style beers will possess a creamier texture and a more evenly distributed flavor, while the normal carbonated beer is less delicate and has a stronger aroma.”

The Nitrogen Movement

“More than just a trend, nitrogen use in the craft brewery is really a movement that’s been continually building and now really coming into its own.”

These are the words of Tyler Jones, Production Manager of Dosing Systems at Chart Industries Inc, headquartered in Ball Ground, GA. He says there are two predominant reasons for this movement.

“One use is to push oxygen out of containers during the brewing process. By containers, we are talking mainly cans for now. There are certain amounts of dissolved oxygen (DO) that we just can’t do anything about,” says Jones. “But we can reduce the total package oxygen (TPO), specifically the headspace oxygen (HO) that is sitting above the beer and trying to get into the product during packaging. If you’re not dosing nitrogen, then your actual parts per billion (ppb) of DO is higher than you initially measured, and that means that you as the brewer, aren’t getting your product out to market in the taste profile that you initially intended.”

“The second reason is nitrogenation of the beer. Many brewers do it in the keg itself. You prefill the keg with gaseous nitrogen, and over time, the beer inside the keg transforms to nitro brew, which is then also pushed through the keg to tap process using only nitrogen. Carbon dioxide is a natural product but slows the nitrogenation process, so most breweries want to pull the carbon dioxide out. Nitrogen filled kegs keep the nitrogen in the beer where it belongs.”

Guinness is, of course, the name most synonymous with nitro brews, and has a patent on their cans featuring that familiar rattling ball. Other cans have a widget installed, which Jones says is about the size of a quarter in diameter and the width of a thumb. The widget contains an orifice with an exit valve and a slit for the in-valve. The brewer puts the beer in, the can is inverted so the liquid just covers the top orifice. As the nitrogen expands, it forces itself into the widget so that when the can is inverted again, the nitrogen is encased within the widget. When the beer is opened, it gets a slight shake or hard pour, charging the system. Nitrogen escapes, invigorating the beer and producing that great cascading pour that accompanies all nitro brews.

But because these cans were expensive and only available if ordered in standard, minimum order quantities, the smaller craft breweries simply couldn’t afford them. That’s when Jones and Chart started their Ditch The Widget program and website, allowing smaller and startup brewers the ability to give their beer a heavy nitrogen dose right on the filling line, immediately before seaming.

“Without giving away too much, it’s all about a pressure situation in the can or bottle. After a short time, the beer is completely nitrogenated, complete with the great taste, the great cascading pour, and the familiar long-lasting, tight head. Just everything. The whole deal,” says Jones. “And better yet, the best results have come when the beer is initially brewed completely flat, without the use of carbon dioxide or nitrogen.”

Dose size will vary due to the beer type as well as the size of can or bottle. One drop of liquid nitrogen expands seven hundred times its volume when going from liquid to gas. That expansion evacuates the oxygen and carbon dioxide that is present while adding pressurization.

Partnering with Left Hand Brewing in Colorado, Chart and Jones have been able to perform intensive nitro testing and help cultivate the nitro industry.

“The Brewmasters help us with testing because they know exactly what they are looking for in the way of head retention, pour and taste. Nitrogen is generally thought to be used with the darker beers, and although that is true, anything can be nitrogen dosed, including IPAs. The main thing is that nitrogen is smaller and less soluble than carbon dioxide, so it creates a creamier mouthfeel for those beers that are already more pleasant than some IPA or hop forward beers. If the beer is actually meant to have a bite to its final taste, then nitro dosing would defeat that purpose.”

Brew Pubs Are Perfect For Sampling

Left Hand Brewing is just one craft brewery that has become a proponent for nitrogen use in the craft beer industry. They continue to offer both nitro and non-nitro options in their milk stouts, allowing a side by side comparison of just how nitrogen dosed beers differ in aroma, taste and appearance. They’ve also been successful with bottling nitro beer. Their bottled Nitro Milk Stout met with wild enthusiasm and great reviews, paving the way for a series of nitro brews that included their Sawtooth Nitro and Wake Up Dead Nitro. By increasing the availability of nitro beers as a to-go product, Left Hand Brewing increases the availability and versatility of craft beer options, while also allowing nitro beer aficionados to be able to take their preferred beer with them away from the pub.

James Cain, co-owner of Vault Brewing Company in Yardley, PA is quick to sing the praises of using nitrogen within his brewery. Vault was the first to package their nitro beers in widgetless cans, opting for inline nitrogenation instead. But Cain also uses nitrogen with some of his traditionally carbonated beers as well.

“Capping our cans using nitrogen is very helpful in removing oxygen from the headspace because of the capacity the nitrogen displaces when transforming from a liquid to gaseous state. It promotes extended shelf life and because of that large amount of displacement, the walls of a beer canned using nitrogen will be noticeably more firm and rigid than their CO2 counterparts. This supports the idea of higher strength cans with better performance and more stacking power. But you have to be mindful that the extra strength is due to increased pressure, so there also is the possibility for more damage. It’s a six-of-one, half a dozen of the other kind of thing.”

“Not many are packaging with nitrogen,” Cain says, “But we feel that it’s a great way for those beer drinkers to be able to take our nitro beers with them for later enjoyment in their homes. They’ve asked if we could do it with our growlers, but it just wouldn’t work, so being able to can the nitro beer is a way to satisfy that customer demand.”

Within his brewpub, Cain says that there are always nitro brew beers on tap, with the choices usually being seasonal and/or session beers. These beers are pushed from keg to tap using a nitrogen system that allows a mixture of seventy-five percent nitrogen to twenty-five percent oxygen ratio.

“It ultimately comes down to personal preference,” says Cain. “Overall, using nitrogen gives a superior, cask-style pour, emphasizing the taste and flavor of the beer. It’s a way to provide a smoother mouthfeel without the fizziness of high carbonation. It takes away the carbonic acid and bite at the end of your drink of beer.”

The Proof Is In The Pour

Nitro beer drinkers notice immediate differences in initial mouthfeel, which plays a huge part in the overall perception of the beer from that point forward. That smoother, creamier, almost dessert-like foam head is all due to the nitrogen immediately forming a glassful of tiny, insoluble bubbles upon pouring.

And that pour is important. With agitation produced from either a mild shake or a fully inverted hard pour, nitrogen is released and those tiny, endless bubbles descend with the signature cascading action that signifies a nitro brew. By the time the container is emptied, those nitrogen bubbles reverse their flow and rise towards the top in a thick, heavy foam head with superior retention, providing the velvety mouthfeel of a luscious whipped dessert. The darker, more intensely flavored stout types of beer tend to better match with the creamier, velvety consistency of nitro brewing, and actually have their flavors amplified when introduced to nitrogen.

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