Nonalcoholic beer is still a tiny portion of the market, but its growth represents an opportunity for breweries to attract new customers. And while much of the equipment used to make NA beer is expensive and beyond the reach of most small breweries, specialized yeast strains are affordable—and brewers know how to use them.
However, making an NA beer worth drinking isn’t as simple as pitching an NA yeast. That’s why researchers at the University of Arkansas decided to test several no- and low-alcohol yeast strains, collecting insights that brewers can use.
“Most of the leading research into nonalcoholic yeast strains has been led by [AB InBev] and Heineken,” says Scott Lafontaine, assistant professor in food chemistry. “We wanted to find strains for craft brewers.”
Lafontaine and his team evaluated 11 strains of commercially available nonalcoholic yeast stains. “This is one of the coolest research projects I’ve been part of,” he says.
Yeast labs have put out a variety of strains in recent years—along with recommendations on how to use them—but there hasn’t been much research comparing what’s available. “Information on commercial strains is generally limited to the yeast laboratories’ own websites,” says Andrew Maust, PhD student at the University of Arkansas under a Distinguished Doctoral Fellowship and coauthor of the study. “So our study provides an independent, third-party review that cuts across the entire yeast market.”
"When looking at the published literature, a lot has been published on new yeast, but not a lot on what is in the commercial market," says Maust.
Evaluating the Options
The strains the Arkansas researchers studied were:
- Escarpment Labs NAY (Hanseniaspora uvarum, liquid)
- White Labs NA All Day (Saccharomycodes ludwigii, liquid)
- White Labs Torulaspora delbrueckii (liquid)
- Lallemand LalBrew LoNa (Saccharomyces cerevisiae, dry)
- Fermentis SafeBrew LA-01 (Saccharomyces cerevisiae var. chevalieri, dry)
- Novonesis SMARTBEV NEER (Pichia kluyveri, concentrated liquid pitch)
- Berkeley NA Cabana (genetically modified Saccharomyces cerevisiae, liquid)
- Berkeley NA Classic (genetically modified Saccharomyces cerevisiae, liquid)
- Omega OYR-252 (genetically modified kveik strain, liquid)
- Omega OYR-439 (hybrid strain, liquid)
- Omega OYL-071 Dried Lutra (kveik strain, dry)
Here’s how they conducted the study: They used each strain to ferment two different worts, with all wort made from 100 percent two-row pale malt. One wort had a starting gravity of 4.5°P (1.018), and the other had a starting gravity of 9°P (1.036). They controlled the fermentability of the wort by mashing at 167°F (75°C)—except for the wort meant for the two strains that are not maltose-negative; for those, they mashed at 176°F (80°C) to further reduce fermentability.
“We used upper and lower ends of a normal range of gravity to accentuate the yeasts' flavor profile,” Lafontaine says. They hopped all wort to 10 IBUs, using iso-alpha extract, and they set the pH at the start of fermentation to 4.6.
They pitched each yeast strain at a rate of 10 million cells per milliliter—not necessarily the pitch rate recommended by each supplier, but a consistent rate meant to ensure comparability.
Finally, a panel of 10 trained sensory evaluators tasted each beer; they first underwent three days of training on 18 aroma and flavor standards and six mouthfeel standards. Each panelist evaluated each beer three times to ensure consistent results from each judge.
The Findings
“Not one of these strains is a one-size-fits-all,” Lafontaine says, offering a key takeaway from the study: “Choose different strains for different beer styles.”
The Arkansas researchers grouped the strains into three buckets: those best for lager styles, those best for wheat beers, and those best for pale ales. They also identified a fourth bucket for sour beers, although Omega OYR-252 was the only acidifying strain evaluated.
Based on the results of the sensory analysis, they concluded:
- The best strains for lager-type beers were White Labs NA All Day and Torulaspora delbrueckii.
- The best strains for wheat beers were Fermentis LA-01 and Escarpment NAY.
- The best for pale ales were Berkeley’s NA Cabana and NA Classic, as well as Escarpment NAY.
“This shows the power of just yeast and grain,” Lafontaine says. The conclusion that you should consider using different strains for different styles should come as no surprise to brewers, who often work with multiple strains for different beers. Yet the Arkansas research is the first to evaluate so many commercial strains and categorize them.
Lafontaine says he was particularly impressed by the performance of the genetically modified strains. Those stains finished fermenting in 24 hours and led to great-tasting beers, according to the sensory evaluation. And, since such strains could be modified to create many flavors, “I see unlimited potential,” he says.
More Details, and Words of Warning
There was a reason to test both low- and high-gravity worts.
“Our hypothesis was that in a nutrient-deprived environment, some of the yeasts would have a stress-modulated response,” Lafontaine says. Generally, the strains produced more volatiles in beers made from the 9°P wort, although Escarpment NAY showed increased ester formation in the 4.5°P beer.
While making low-alcohol wort with the specialized yeast strains is relatively easy, Lafontaine cautions brewers on the importance of food safety. In the absence of alcohol, and with typically low hopping rates, microbial growth is a real concern.
“Fermentation should be quick,” he says. “The longer the fermentation time, the more chance there is of spoilage. We drew a line in the sand at 72 hours, by which fermentation had to be complete. … Another line in the sand was a pH below 4.0.” If fermentation didn’t bring the pH below that level, the researchers adjusted with acid to get there.
Lafontaine also advises brewers not to re-pitch these yeast strains because the risk of contamination in the slurry is too high. “Saccharomyces is everywhere,” he says. “We don’t have a playbook yet on how best to handle these strains. Brewers need to exercise extreme caution.”
Finally, Lafontaine says that some of these yeast strains have smaller cell sizes, and some are poor flocculators. As a result, it may be necessary to filter the beer—and even then, traditional brewery filters might not suffice.
Caveats
Beers created in lab setting aren’t the same as those developed for commercial sale, so the results won’t be identical, either. In this study, the wort was all the same, not designed for each beer style, and the pitch rates didn’t follow the yeast labs’ recommendations.
“These weren’t finished, designed beers,” Maust says. “They were laboratory tests.”
Lafontaine also advises brewers to rethink conventional brewing wisdom when it comes to NA beers. “What we may consider a flaw—diacetyl, DMS, or whatever—these are beer-like characteristics, and a little of them could actually help make a nonalcoholic beer more reminiscent of full-strength beer.”
The Future of Low- and No-Alcohol Beers
Advances in yeast genetics offer particular promise for nonalcoholic beer.
“As we start to identify the characteristics we want for flavor, we should go back to yeast banks and screen for those flavors,” Lafontaine says. However, “screening should be different for nonalcoholic strains. Previously, screening was at least in part for managing fermentation characteristics. But with nonalcoholic strains, strains could be screened for food-safety characteristics, then bred or evolved for the flavor characteristics."
He says that he hopes the research moves in that direction.
“Where science can take us from here is the future,” he says. “As we start to learn how to control these fermentations, then we could start blending yeasts, or blending yeast with bacteria. For example, the bacteria could help lower pH while yeast produces ‘beer’ flavor.”
And while smaller breweries may not be able to afford the fancy equipment that larger ones use to make NA beer, there are advantages to relying on the specialized yeasts.
“Physical de-alcoholizing systems strip out flavor while they strip out alcohol,” Maust says. “Making nonalcoholic beer through specialized yeast keeps volatiles in the beer and keeps hop flavor in the beer.
“Yeast is the first accessible point to design … nonalcoholic beer,” he says. “If you can pitch yeast, you can make delicious nonalcoholic beer.”