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Saving the Pint: How a CO2 Shortage is Changing Beer Brewing

As access to CO2 levels has declined, breweries are looking towards recovery systems and nitrogen for solutions.

Overhead view of beer cans at Dorchester Brewing
Serious Eats / Sasha Pedro

Visit the Coliseum in Jackson, Mississippi, on most nights that the arena is hosting a concert, and you'll see a familiar scene—crowds of music fans packing in to listen to their favorite artists. Some will have plastic cups of foamy beer in hand. None, most likely, will be thinking about how that beer connects with what's far below their feet. Down through the Coliseum's floor, down through the foundation, through layers of topsoil and rock, down a good 2,900 feet lie the remains of a massive ancient volcano, now extinct. The land above the volcano is today known as the Jackson Dome thanks to its noticeable elevation, which, in turn, is a remnant of the volcano that was once a mountain that rose high above ancient seas.

Last erupting about 66 million years ago in a devastation of lava and ash, the volcano is now kaput, but far underground it left behind some of the biggest wells of carbon dioxide gas in the nation, which were discovered in the 1970s. For decades, the beer industry, among others, has relied on that CO2 to flush hoses, move beer from tank to tank, and, yes, to carbonate their kegs, bottles, and cans. It's not impossible that some of the beer sipped in the Coliseum has at times been full of gas extracted from way down below without the drinker ever realizing it. Until earlier this year, that is, when CO2 at Jackson Dome became contaminated, further threatening the supply of carbon dioxide amidst a larger nationwide shortage.

Sideview of a draft beer being poured at Dorchester Brewing
Serious Eats / Sasha Pedro

CO2 is an essential component of beer. Think of the melodious hiss that comes with opening a fresh can of pale ale and watching the foamy head form while you pour the liquid into a glass. As you swirl the liquid, the carbon dioxide rushes to the top, and the cloudy liquid slowly becomes clear. Each sip is filled with tiny little bubbles. With the exception of cask ale, there can be no beer without carbonation.

Carbon dioxide is the byproduct of many natural processes: It's created when organic matter decays or combusts, and during fermentation when yeasts feed on sugars to produce alcohol. The amount of CO2 a beer produces is directly linked to alcohol by volume (ABV): The more sugar the yeast consumes, the higher the ABV and carbon dioxide levels. But the CO2 found in your favorite fizzy drinks is usually a food-grade version that’s collected as a byproduct of ethanol and ammonia production.

The beginning of the CO2 shortage started with pandemic-related shutdowns in 2020, when ethanol production came to a halt. Two years later, production levels still haven’t returned to normal. With the supply of carbon dioxide from the Jackson Dome jeopardized, brewers are looking for alternative sources of the gas—and even attempting to capture it themselves.

“Most craft breweries are too small to invest in the system—it doesn't make a lot of financial sense for them,” says Mandi McKay, Director of Sustainability and Social Responsibility at Sierra Nevada Brewing Company. “But once you hit a certain growth or volume size, it makes a lot of sense to invest in a recovery system.” 

Overhead view of tanks at Dorchester Brewing
Serious Eats / Sasha Pedro

Sierra Nevada Brewing Company has strapped what looks like a huge blimp to their ceiling. The balloon collects the CO2 that’s normally released during the natural fermentation of beer. Once the carbon dioxide is in the balloon, any water-soluble contaminants like ethanol are removed and the gas goes into a storage tank for usage throughout the brewery, including the process of force-carbonating beer. The business installed the system in 2003 as part of their commitment to sustainability, and they have since become self-sufficient by relying on it for their packaging needs, transporting beer from tank to tank, and even using it for their draft beers in the taproom. 

For some companies, like the Alaskan Brewing Company and the Maui Brewing Company, carbon dioxide recovery systems were a necessary investment. Marcy and Geoff Larson, the founders of Alaskan Brewing Company, opened their brewery in 1986—but because of their remote location in Juneau, bringing in carbon dioxide was a challenge. The Larsons decided to install their recovery system in 1998. “It was the smallest system installed in the US, so there was a bit of learning on all parts and parties, but we were able to troubleshoot and get the system dialed in,” Geoff tells me. 

Like Sierra Nevada, the Larsons haven’t had to bring in carbon dioxide since installing their own system. “We now know exactly where the CO2 comes from—malt and fermentation,” says Geoff. “That’s why we call it Beer Powered Beer!”

A brewing tank at Dorchester Brewing
Serious Eats / Sasha Pedro

Garrett Marrero, founder of Maui Brewing Company, echoed the same sentiments. Located in Kihei, Hawaii, Marrerro noted that the cost of shipping carbon dioxide to the island was ten times the amount of what brewers were paying on the mainland. Like Sierra Nevada Brewing Company and the Alaskan Brewing Company, Marrero’s business uses a recapturing system to reduce their reliance on imported CO2.

While carbon dioxide recovery systems have allowed craft breweries to maintain independence from outside sources, that doesn’t mean they’re without their challenges. The initial installation is often a huge investment—especially with rising CO2 costs. Some companies, like Earthly Labs, offer leasing to help offset costs. They estimate that breweries can see a return on their investment within two to three years or less, depending on the cost of carbon dioxide in their area. Maui Brewing installed their recapturing system—not an Earthly Labs product—and saw a return on their investment within a year. 

But as breweries vary their product line by adding items like kombucha and hard seltzer, it limits the amount of carbon dioxide the brewery can produce overall. Typically, hard seltzers aren’t brewed, but are a blend of grain alcohol, water, and flavoring; though they aren’t fermented in the brewery, the beverages still require carbon dioxide.  “What's happened in the last five years, as [Sierra Nevada] has shifted the products that we make has impacted how much CO2 is available or is being generated in fermentation,” says McKay.

Sierra Nevada has only had to outsource CO2 once or twice in the last couple of years, but it may become more of a concern as their product lineup changes—something that Maui Brewing has begun to think about. “At one point we [decreased our dependance on outside CO2] by 80%,” says Marerro. “But as we continue to grow, it’s probably closer to 30-35%.”

Some brewers predict that CO2 recovery systems will be as common as their centrifuge, a piece of equipment that clarifies beer. Centrifuges were once a novelty, but now most craft brewers have them. “We certainly are at the tip of that spear,” says George. “We've had a lot of early adopters help us make the technology better, and we'll continue to innovate to make it more affordable and accessible to more breweries.” 

When Dorchester Brewing Company found out that their carbon dioxide provider could only provide 25% of their original allotment, the company immediately went into action to reduce their usage across their operation. “In many cases, crises do foster invention and change,” says Matt Malloy, CEO of Dorchester Brewing Company. “It’s forcing us to think differently, and the reality is, it’s actually pushing us to be better.” 

The spunding system at Dorchester Brewing
Serious Eats / Sasha Pedro

Malloy’s team started with spunding, a German technique for naturally carbonating beer that involves attaching a valve to the tank in late fermentation when all the natural gas is let out. The valve allows brewers to control the release of CO2, allowing them to carbonate the beer naturally. With this method, says Malloy, you get better flavor, aroma, and use of hops—and you’re self-carbonating your beer.

In other areas of their operation, such as canning, kegging, and moving beer from their fermenter to their Brite tank, which helps clarify the brew, Dorchester has replaced CO2 with nitrogen gas. Traditionally, carbon dioxide costs less than nitrogen, but brewers like Malloy have turned to the gas because the current cost of CO2 is high and the availability is low. 

Malloy explains that breweries can’t eliminate the need for carbon dioxide completely from the brewing process, but they can reduce it. So far, Dorchester has reduced their need for the gas by 30-35%. Instead of having carbon dioxide delivered once a week, they can now stretch their supply to two weeks. But Dorchester Brewing Company isn’t stopping there. They are continuing to make their operation less dependent on CO2 and sharing their findings with other breweries who are looking to do the same—something Marrerro is doing, too.

“We’re suckers for being number one,” he says. “I don’t mean that as number one as the top, but the guinea pig number one. We’re always forward thinking in that way.” The new system Maui Brewing is looking at implementing is direct air capture (DAC), which captures carbon dioxide from the atmosphere and then injects it into the earth. Marrero is currently working with the company Air Capture to install a system that would allow Maui Brewing to use the captured CO2 in their brewing operations. 

Nitrogen tanks at Dorchester Brewing
Serious Eats / Sasha Pedro

The goal of the system is to zero out their carbon dioxide demand at the brewery and also on the entire island of Maui. “Essentially, we'd be cleaning the air here and then using that CO2 in our process. We're looking to break ground on that project here in the next couple of months,” says Marrero. He estimates it will take a year before the operation is up and running, but Maui Brewing would be the first brewery in the world to use DAC in their brewing operations.  

Down the line, Marrero hopes to supply the businesses on the island of Maui with sustainable carbon dioxide. “We want to make sure that we can help affect positive change in the environment and in our community through the efforts that we invest in,” he says.

It's predicted that CO2 shortages will become a regular occurrence, but craft brewers are using their ingenuity to meet the problem with a solution—a necessary step to ensure a long future of tall glasses of beer with that fluffy, bubbly head.