By: Alyssa L. Ochs
For many years, carbon dioxide has been used in brewing and distilling processes. Recently, some producers have switched from CO2 to nitrogen or use both CO2 and nitrogen because each has unique advantages. To help make the right choice for your operations, here are a few things to think about regarding the use of carbon dioxide and nitrogen for craft beverages.
Using CO2 in Breweries & Distilleries
For brewing and distilling, beverage producers use CO2 to remove air and protect the product from oxidation. This ensures good taste, mouthfeel, quality and shelf stability. CO2 can be pumped into kegs and kept at pressure to carbonate beer and give it a foamy texture. CO2 is often transported as a cryogenic liquid, which requires trailers and railcars for transportation.
Ken Hoffman, vice president of sales for Allcryo, Inc., told Beverage Master Magazine that the first factors his company considers for CO2 tanks are tank size and monthly use volumes. He also said to consider the proximity of the use site to the supply source. Based in Montgomery, Texas, Allcryo manufactures, refurbishes and services cryogenic tanks, CO2 tanks and related equipment.
“With a refrigerated CO2 tank, you can have more storage than you might need because there is no loss of product,” Hoffman said. “It is important not to have an undersized tank, as the expense of additional delivery charges and the threat of run-outs is far more expensive than the savings of buying a smaller tank. It is also important to size for future growth.”
Using Nitrogen in Breweries & Distilleries
Nitrogen serves some of the same purposes as CO2 in craft beverage production, such as protecting against oxygenation, extending shelf life and improving taste and aroma. Nitrogen is used in pressurized containers and can be incorporated before or after filling and before capping and seaming. For small breweries, nitrogen often comes in liquid form from gas distributors. For larger nitrogen needs, it can be transferred from a supply tank using vacuum-insulated piping.
Vacuum Barrier Corporation is a cryogenic engineering company that manufactures vacuum jacketed piping and equipment for use in multiple industries, including breweries and distilleries.
“Our Semiflex and Cobraflex vacuum jacketed piping are used to safely and efficiently transfer cryogenic liquid nitrogen. Our Nitrodoser systems are used for inerting or pressurizing containers and for nitrogenating beer and coffee,” Dana P. Muse, the international technical sales engineer for Vacuum Barrier Corporation, told Beverage Master Magazine.
Allcryo also offers systems for liquid nitrogen, and Hoffman said that the primary application of their products is to strengthen thin-walled plastic bottles and aluminum cans.
Equipment Needed for CO2 and Nitrogen
Specialized equipment is needed to facilitate the use of both CO2 and nitrogen in beer or spirits production.
“The Vacuum Barrier Nitrodoser system drops a single dose of liquid nitrogen into the top of the container just before the cap or lid is applied,” Muse said. “The drop of liquid nitrogen is trapped inside the container, and as it evaporates and warms up, it expands, pressurizing the container.”
Muse said that for pure spirits, a plastic bottle could benefit from some internal pressure to reduce jams on the filling line, improve stacking strength, improve storage efficiency and improve the product appearance.
“We have also seen an increase in the market for pre-mixed cocktails in aluminum cans,” he said. “Carbonated cocktails, like a Cuba Libre or Moscow Mule, already have internal pressure created by the CO2. However, still cocktails, like a margarita or a screwdriver, in an aluminum can are extremely flimsy and easily crushed without internal pressure created by liquid nitrogen.”
For breweries, liquid nitrogen has two different applications. On a canning line or a bottling line without a pre-evacuation system, a drop of liquid nitrogen into the empty container purges out oxygen and creates an inert atmosphere. This helps reduce the amount of dissolved oxygen in the beer to improve the shelf life. Liquid nitrogen is also used for nitrogenated beers in single-serve containers.
“A drop of liquid nitrogen in the headspace will pressurize the container, and under the right conditions, the nitrogen will dissolve into the beer over time,” Muse said. “When the container is opened, the nitrogen will come out of solution and create the cascading bubbles and creamy foam that customers expect. However, in order to get the nitrogen to come out of solution quickly, either the container needs to have a ‘widget,’ or the consumer needs to be aware of how to ‘hard-pour’ the beverage. Without a widget or a hard pour, the nitrogen will not create the cascade or foam, and the beer will be flat.”
Tanks for CO2 and Nitrogen
Breweries and distilleries can buy a new or refurbished foam insulated tank for their equipment. Allcryo’s refurbished tanks are a cost-effective solution that performs as well as new tanks because the refurbishment process comes with a warranty and includes all-new, two-part poly-foam insulation, paint, pipes and safety valves.
“Typical cost savings on a refurbished tank over a new tank is between 20% and 30%,” said Hoffman. “If purchasing a new, refurbished or used vacuum jacketed tank, it is extremely important that the vacuum is sound and the tank is complete with refrigeration coils that afford the opportunity to add refrigeration if the vacuum becomes compromised. The coils are necessary to allow pressure control and avoid the possibility of high pressure and venting of CO2.”
Both the foam insulated and vacuum jacketed tanks are offered by Allcryo and work well under most conditions, with the significant differences being cost, application and the installation site.
“A vacuum jacketed tank does not require electricity, but the ability to control pressure in the tank is limited without an inner coil,” Hoffman said. “With a foam insulted tank, the refrigeration loop maintains the liquid CO2 in a constant pressure range. The system is set to automatically kick on when necessary, and the balance of the time is not running.”
Concerning installation, Hoffman said that most vacuum jacketed tanks are vertical and require a substantial foundation. However, a horizontal tank might be more affordable if there is enough space available.
Pros & Cons of CO2 and Nitrogen
CO2 is the industry standard, which means that it is readily available and well-tested for craft beverage purposes. However, CO2 can be challenging and expensive to transport. Also, recent shortages of CO2 have slowed production for some beverage producers.
Nitrogen offers a unique mouthfeel and smoothness because it is less soluble than CO2. Yet, it is not beneficial for hop-forward beers that are meant to have a bite to them rather than a creamy consistency. Nitrogen can be used for various applications, including cleaning, pressurizing and inerting. These applications make it a practical choice and cost-efficient since it is often cheaper than CO2, especially with onsite nitrogen generation. With onsite generation, a producer can be more efficient without waiting for a supplier’s delivery or wasting gas. It may also be a way to reduce the company’s carbon footprint since nitrogen releases fewer greenhouse gas emissions.
Some beverage producers are using CO2 and nitrogen blends to meet their needs. However, no other substitutes have proven effective for these purposes at a cost-effective rate.
Safety Considerations for CO2 and Nitrogen
Working with CO2 or nitrogen in any capacity can be dangerous without the proper training and safety protocols in place. Gas can collect at the bottom of tanks and spill out onto the floor to create hazards. Production facilities should have a gas detection system to alert workers to dangers or automatically activate ventilation systems. Preventative maintenance should include testing tanks for residue buildup and ensuring that gas supply lines do not have condensation or standing liquid inside. In-line filtration can be used to scrub away undesirable chemicals and moisture that collects during the production process.
“Most people understand liquid nitrogen is cold enough to cause frostbite and cold burns if it directly contacts the skin,” Muse said. “Cryogenic gloves and face shields should be used anytime there is a risk of direct exposure to the liquid nitrogen.”
Liquid nitrogen should only be used in a well-ventilated area, where it may be necessary to install oxygen monitors. Also, nitrogen expands to 700 times its original volume when it changes from a liquid to a gas.
“We use this expansion to pressurize or purge out oxygen from containers, but if there is a nitrogen leak, it could eventually push all the air and oxygen out of an entire room,” Muse said. “If someone enters an area without enough oxygen, it can cause asphyxiation and death. Proper ventilation and oxygen monitors help minimize this risk.”
Vacuum Barrier provides pressure relief valves at critical locations to eliminate the risk of over-pressurizing and prevent explosions. If too much liquid nitrogen becomes trapped inside a sealed volume, the expansion from liquid to gas could create enough pressure to explode. Relief valves must be set at the correct pressure, so if they must open, the gas escapes in an area away from people.
“Vacuum Barrier works with each of our customers to ensure that any personnel working with or near our equipment will have the correct training for proper and safe handling of liquid nitrogen,” Muse said.
“To help mitigate the risk of asphyxiation, it is very important to monitor the atmosphere in process areas to ensure that OSHA-mandated oxygen levels are maintained,” Hoffman from Allcryo said. He also suggested producers install alarm systems to constantly monitor the atmosphere and warn of dangerously low oxygen content.
Both liquid CO2 and liquid nitrogen are stored at very low temperatures and can cause injury if not handled properly. “Allcryo can work with site safety personnel and assist in the design and installation of safety systems,” Hoffman said. “Allcryo can also provide input on foundation design to meet seismic and wind load requirements of the specific location and provide guidance on NFPA-adjacent exposure requirements, such as proximity to overhead electrical wires, sewer drains and vehicular traffic.”b
Expert Advice Goes a Long Way
CO2 and nitrogen can be great choices for a brewery or distillery, depending on its specific needs and production level. When making this decision, make sure to communicate your needs and goals with your supplier to assess the risks and maintain top quality.
Muse from Vacuum Barrier said that for anyone considering using liquid nitrogen for any reason, the most important thing to do is speak with an expert.
“Certainly, talking with coworkers and associates in the industry who have experience with liquid nitrogen might provide some basic information, but they might also pass along some bad habits or incorrect assumptions,” Muse said. “Many people get frustrated when first trying to use liquid nitrogen and jump to the conclusion that it doesn’t work when in reality, they might just be using it incorrectly. Not only is this a waste of time and effort, but if not handled properly, there is a risk of injury.”