In this brief article, we will be discussing how to nitrogenate beer, as well as some interesting facts and nitro beer.
Use of nitrogen gas has gradually become integrated and irreplaceable in the brewing industry and in almost all beer-making processes. Read on to find out what nitro beer is and some interesting facts about it.
How to Nitrogenate Beer?
Brewers can make nitro beer by mixing nitrogen and carbon dioxide under increased pressure.
Nitrogen is typically used in conjunction with widgets (in-package foam generating device) or as “bar gas” for the draught dispense of beer via the delivery orifice that ensures the proper level of bubble formation. Widgets work as nitrogen foam nucleating devices (1).
As opposed to carbon dioxide, nitrogen is extremely resistant to dissolution. This characteristic is exploited to produce nitrogenated beer with high keg pressure and low carbonation.
The pressure applied to produce nitrogenate beer depends on the type of beer. For instance, for a stout, around eight psi of pressure is enough to nitrogenate the brew and give it a creamy texture and good head.
What is the Process of Nitrogenation?
After perfecting the beer to gas ratio, beer can be nitrogenated by two methods: draft or canned nitrogenation.
For pouring draft beers, specific nitro draft beer pouring technology known as a ‘resistor plate’ is connected to the tap just before the beer faucet. The perforated plate forces the beer through its holes while rapidly changing pressure.
Since nitrogen is insoluble, extra pressure from the nitrogen cylinder and regulator is required to manufacture drinkable beer. This extra pressure produces the small nitrogen bubbles characteristic of a nitro beer as the gas diffuses into the liquid.
The process of nitrogenation inside the brewery utilizes specially rated tanks and/or specialized packaging equipment that is required to infuse the beer with nitrogen. While carbon dioxide occurs naturally during fermentation and can be force added to beer at lower pressures, the less soluble nitrogen requires higher pressures to dissolve in beer (2).
Why Are Gasses Infused In Beer?
Gasses perform vital functions to enhance the taste of different beers and to provide the distinct effervescence that beer lovers crave.
Depending on what gas is infused in the beer, brewers can create a creamy brew or a fizzy and refreshing beverage.
Moreover, gasses also determine how long the ‘foam beer head’ lasts, while the correct ratio of gasses helps sustain the brew’s desired flavor.
Procedures that rely on foam generation by “natural” pouring techniques tend to be inconsistent, while “artificial” foam generation by gassing through porous frits or by other methods produces foams that are not typical of consumer dispense (3).
Why Do Brewers Nitrogenate Beer?
Disproportionation is the process by which the gas from smaller bubbles with higher Laplace pressure diffuses into larger bubbles with lower Laplace pressure. Thus, smaller bubbles disappear and larger bubbles become even larger, resulting in bigger, “bladdery” bubbles that are less attractive. Because nitrogen is less soluble in beer than carbon dioxide, disproportionation is less in beers using a mixture of these gasses, resulting in greater foam stability (3).
Modern nitrogenation helps mimic traditional beers’ creamy and mouthfeel appeal. This process also maintains the quality and superior standard of these richer-tasting beers.
Nitrogenation minimizes the process of hand-pulling cask ales and thus reduces inconsistencies due to human error.
Moreover, with improvement in nitrogenation technology, drinkers can enjoy nitro beers in smaller quantities without stressing about mass spoilage of the brew.
What is the Gas Composition of Nitro Beer?
A typical gas blend for nitro dispense is 25% CO₂/75% N₂. Nitro-beers generally can also contain 30 percent carbon dioxide and 70 percent nitrogen (2).
The lack of oxygen in nitrogenated beers ensures that they are not oxidized and makes them retain their flavor for longer.
What are the Disadvantages of Using Tanks to Nitrogenate Beer?
Using tanks to nitrogenate beer has certain disadvantages (2).
- Tanks are bulky, heavy, and laborious to handle.
- Tanks need a safe and well-ventilated storage area in case of accidental leakage.
- For nitrogenating larger volumes, many large stainless-steel vessels are required.
- Filling a pressure vessel, infusing nitrogen, and transferring beer to a keg causes loss of dissolved nitrogen. This reduces the mouth-feel and head of the beer.
- Many jurisdictions require any tank that is pressurized above 14.7 psig to carry an American Society of Mechanical Engineers (ASME) stamp
Should Beers Be Nitrogenated?
Nitrogenated beers are quite different from conventional carbonated beers, which is why certain beer experts do not acknowledge it as a genuine beer product.
Moreover, since nitrogenation involves adjusting beer-gas ratio and utilizing specialized equipment, certain experts don’t regard nitro beers as a true representation of the art of brewing.
Another issue is with consumption time. Beer lovers state that nitrogenated beer should be consumed within 30 minutes, otherwise it tastes flat.
Also, investigations have found that in comparing blind-folded with sighted judging of conventionally carbonated beers the visual impact of the foam head on a glass of beer is more important than the tactile impact on beer flavor and mouthfeel. Consequently, the acceptability of nitrogen as a palliative option will depend on the beer style and consumer preferences (1).
Carbonation or Nitrogenation: Which is Better?
Both carbonation and nitrogenation have their pros and cons for producing beer.
Carbonation is a widely used conventional approach that produces a brew with bigger bubbles and a more exciting, coarse feeling on the tongue.
On the other hand, nitrogenated beer produces a brew with smaller bubbles and a more suppressed taste.
However, if properly executed, both methods can produce a superlative brew with rating based on individual expectations of what beer should taste and look like.
The recommendation is that nitrogen should be used in conjunction with CO2 to gasify keg-conditioned beers. The gas mixture creates a “smoother” beer, with a creamier and more consistent head, due to the lower partial pressure of nitrogen. A disadvantage of this method is that the direct injection may drag the CO2 out of the beer, requiring more time and expense with gasification (4).
Other FAQs about Beer that you may be interested in.
In this brief article, we answered the question of how to nitrogenate beer. Whether or not you regard nitro beer as a true beverage or just a passing trend, it is wholesome, creamy, and now you know how to make it!
If you have any more questions or comments please let us know.
- Evan Evans, T. I. A. R., and Charlie Bamforth. Not just froth and bubble! 2008. University of Tasmania, Australia
- Brewers Association Facts About. 2020. Serving Nitrogenated Beer.
- Evans, D. Evan, and Marian C. Sheehan. Don’t be fobbed off: The substance of beer foam—A review. J Am Soc Brew Chem, 2002, 60, 47-57.
- Ambrosi, Alan, Nilo Sérgio Medeiros Cardozo, and Isabel Cristina Tessaro. Membrane separation processes for the beer industry: A review and state of the art. Food bioprocess technol, 2014, 7, 921-936.