Crafting Zero Booze, Full Flavor: The Yeast Revolution in Non-Alcoholic Beers

Aug 1

Prologue

I was lucky enough to attend the MBAA Northwest District fall meeting in 2022. There, Eryn Bottens –Brewing Manager NPD for Sam Adams/Boston Beer Co gave a fantastic overview of the methods they used to identify the most effective yeasts for non-alcoholic beer production, and their newest beer “Just the Haze”.

The methods they identified included modified fermentation (arrested fermentation), maltose negative yeast, thermal alcoholizaition (using spinning cone column and vacuum rectification) and reverse osmosis. The flavor quality from biological methods were identified as worty, grassy, sweet and missing a beer profile. The mechanical methods yielded watery, thin, lacking mouthfeel, with acidic qualities and again, lacking the beer profile we know.

They moved forward to analyze the following yeasts for their performance and potential in NA beer. S. ludwigii(Control) S. rosei, S. dairensis, Cyberlindera misumalensis, Cuberlindera saturnus, Kazachstania servazzil, Pichia kluyveri, and Torulaspora delbrueckii. Their final method to create this incredibly full bodied hazy non-alcoholic beer involved both arrested fermentation, de-alc procedures and, what I will be discussing in the following article, the use of Sacchromyces ludwigii.

I review these methods and the taste of beers in my latest podcast episode, which you can find here.

Introduction- NABLABs

The craft brewing industry has experienced a significant shift towards non-alcoholic and low-alcohol beers (NABLAB). Despite a global stagnation in overall beer consumption, interest in these 'healthier' and more responsible options is on the rise (De Clippeleer et al., 2023; Myncke et al., 2023). This surge in interest presents both an exciting opportunity and a considerable challenge for craft brewers who seek to balance the appeal of NABLABs with maintaining the flavorful profiles that define their products.

Alcohol-intolerant

To fully understand how these organisms work, we have to review what sugars are involved in the brewing process. In beer brewing, two of these types are maltose and maltotriose, deriving from the barley. These sugars are particularly important because they make up a large portion of the food that yeast consume during beer fermentation to make alcohol.

Now, when we say a yeast is 'maltose-negative' or 'maltotriose-negative,' we mean that this particular type of yeast cannot consume or digest maltose or maltotriose. Just like some people are lactose-intolerant because they can't digest the sugar lactose found in milk, these yeast strains are 'intolerant' to the sugars maltose or maltotriose.

This characteristic of being maltose- or maltotriose-negative is critical to the research on non-alcoholic and low-alcohol beers. Here's why: if the yeast can't eat these sugars, it can't produce as much alcohol. By choosing to use maltose- or maltotriose-negative yeast in the brewing process, brewers can control and significantly reduce the alcohol content of their beer, creating low-alcohol or even alcohol-free beers. This provides a promising and energy-efficient alternative to traditional methods of reducing alcohol content in beer, like distillation or nanofiltration, which can be costly and require a lot of energy.

Therefore, the following research offers valuable insight for craft brewers looking to expand their offerings to include more non-alcoholic or low-alcohol options, catering to the growing consumer interest in such products.

An Emerging Market

The traditional method of producing NABLAB involves removing ethanol from regular beer via distillation or nanofiltration, processes that incur high investment costs and require substantial energy and water consumption (De Clippeleer et al., 2023; Myncke et al., 2023). Recognizing the drawbacks of this approach, craft brewers have increasingly turned to alternative yeasts capable of fermenting without producing substantial alcohol, particularly maltose- and/or maltotriose-negative yeasts.

Despite these strides, there's been little in the way of comparative studies among commercially available alternative yeasts until now. Two groundbreaking studies conducted by researchers from the Department of Biotechnology at UGent, Belgium, offer a comprehensive comparative analysis of nine different commercial NABLAB yeasts (De Clippeleer et al., 2023; Myncke et al., 2023).

Tasting the Difference: Yeast Strains for Non-Alcoholic Brews

The studies demonstrated significant variability in the beers' flavor profiles, chemical characteristics, and microbiological stability based on the yeast strain used.

The Pichia kluyveri strains (NEER™, NEER™Poly, and NEER™Punch) produced beers that were notably fruity and sweet, thanks to their higher ester production (De Clippeleer et al., 2023; Myncke et al., 2023). Beers brewed with maltotriose-negative Saccharomyces cerevisiae (LaBrew®London and LaBrew®Windsor) generated higher amounts of higher alcohols, resulting in a bitter taste due to less residual sugars (De Clippeleer et al., 2023; Myncke et al., 2023).

Conversely, beers made with Torulaspora delbrueckii (WLP603) and Saccharomyces cerevisiae var. chevalieri (SafeBrew™LA-01) achieved a more balanced profile, being less bitter than the LaBrew® beers and less sweet than the Pichia beers. SafeBrew™LA-01 also stood out for its phenolic flavor and exceptional mouthfeel, shared with the Pichia beers (De Clippeleer et al., 2023; Myncke et al., 2023).

Techniques for Enhancing Aroma and Flavor

While alternative yeasts offer an exciting avenue for the production of NABLABs, further research by Lin et al. (2023) and Sileoni et al. (2023) provide additional avenues for enhancing the flavor and aroma profiles of these beers.

In a study by Lin et al. (2023), proteases were used to optimize the wort amino acid profile for improved aroma production during yeast fermentation. The research highlighted how different yeast strains responded variably to the modified wort, impacting the aroma output significantly.

Moreover, maintaining the flavor stability of NABLABs is critical. The challenge is particularly poignant for craft brewers, who often eschew pasteurization and filtration to maintain flavor integrity. Sileoni et al. (2023) addressed this issue by testing the flavor stability of an unpasteurized and unfiltered low-alcohol beer during 120 days of cold storage. Remarkably, the beer remained stable for the entire duration, signifying the potential of cold storage in maintaining flavor stability without resorting to pasteurization.

Implications for Craft Brewers

These findings are highly relevant for craft brewers. For those seeking to break into the NABLAB market, the comparative study of different yeasts offers a valuable reference for choosing the most suitable yeast for their specific flavor profiles. The research by Lin et al. (2023) and Sileoni et al. (2023) further provide a roadmap for enhancing and maintaining the aroma and flavor of NABLABs, critical aspects for craft brewers dedicated to providing high-quality products. While there are numerous methods involving physical removal of alcohol, advances in yeast suited for this application have made great advances and are an excellent option for brewers looking to create a beverage for this segment.

As the market for NABLABs continues to grow, these advances will be instrumental in helping craft brewers meet consumer demand without compromising the distinctive flavors that make their brews unique.

References

De Clippeleer, J., Myncke, E., Huys, J., et al. (2023). An in-depth comparative study between commercial alternative brewing yeasts in low-alcohol and alcohol-free beer production. ASBC meeting, Abstracts.

Lin, C. L., Petersen, M. A., & Gottlieb, A. (2023). Increasing Higher Alcohols and Acetates in Low-Alcohol Beer by Proteases. Molecules, 28(11), 4419. https://doi.org/10.3390/molecules28114419

Myncke, E., Huys, J., Laureys, D., et al. (2023). Non- and low-alcohol beers: an in-depth comparison of commercial alternative brewing yeasts. Trends in Brewing, 15th, Abstracts.

Sileoni, V., Maranghi, S., De Francesco, G., Perretti, G., & Marconi, O. (2023). Flavour Stability of a Cold-Stored Unpasteurized Low-Alcohol Beer Produced by Saccharomycodes ludwigii. Food and Bioprocess Technology.

Shanleigh Thomson