Approaches to Non-Alcoholic Beer Fermentation

Why non-alcoholic beer?

For several years, Escarpment Labs has invested in research and development into yeasts for brewing non-alcoholic beer, testing many different yeast strains in our collection.

Why would anyone drink non-alcoholic beer though? We get asked this question a lot, but non-alcoholic beer is rapidly gaining momentum among craft brewers due to changing consumer preferences toward healthy drinking, as well as the implementation of government regulations on zero tolerance to drunk driving.

For the craft brewing industry, producing low to no-alcohol beer (0.5% ABV or less) provides an opportunity to offer value to customers who have reduced their alcohol consumption or who don’t consume alcohol. Based on the trends, some are estimating that the non-alcoholic beer market could end up being worth 4.6 billion dollars by 2024.

How is non-alcoholic beer made?

Many common approaches to the production of non-alcoholic beer rely on the use of expensive and specialized equipment to remove ethanol from beer that only works at scale. Not only is this process expensive for craft brewers, but it also results in the removal of volatiles and other flavor compounds which impact the overall quality of the beer. To get around this challenge, novel biological approaches are being used by small breweries to produce low alcohol beers instead of using filtration to remove alcohol from beer.

Biological approaches come with minimal extra costs and involve the use of yeasts that poorly ferment maltose and maltotriose in wort. Breweries do not have to repurpose their existing infrastructure adopting maltose negative yeasts for the production of non-alcoholic beer. Since maltose consumption is a common trait of most of the beer yeasts we use, wild and non-conventional yeasts are gaining attention for use in the brewing of non-alcoholic beer.

Non-conventional yeasts such as Hanseniaspora, Torulaspora, Saccharomycodes, **and Brettanomyces can produce unique flavour compounds that have a lot of value in masking the worty flavour of non-alcoholic beers.

Certain modifications in the brewing protocol can further help the brewer achieve their goal of making low alcohol beer.

  1. The mashing protocol can be modified to reduce the fermentable sugar content in the wort which will in effect lower the amount of ethanol that can be produced when the low gravity wort is fermented.
  2. Fermentation at low temperatures will reduce the metabolic activity of the yeast thus lowering the amount of ethanol produced.

In this blog post, we highlight strategies being developed to produce non-alcoholic beers which could significantly reduce the cost of production of such beverages.

If you’re curious to make your own non-alcoholic beer, check out NAY - our first commercialized maltose-negative yeast.

Wort Composition

To produce non-alcoholic beer, one needs to control the composition of their wort. Standard wort production results in a sweet liquid that is high in maltose. Although maltose is not as sweet as other sugars such as glucose or sucrose, the average drinker will easily be able to detect a wort-like sweetness from a product that is produced with a high concentration of maltose.

Aiming to reduce the maltose composition of the wort is a highly recommended technique to reduce the risk of product instability where the product is not chemically or biologically stabilized post-fermentation. A high concentration of residual sugars could result in microbial contamination.

Wort composition can most easily be adjusted via grist composition and mashing temperature. For simple pale worts, restrict base malts to no more than 50% of the total mash. Utilize other malts that improve foam stability and improve the perceived body to ensure that the final product looks and tastes like a beer.

Aim for short mashes at temperatures above 72°C to obtain more dextrins but less maltose during the mash. If you have tight control over your mash pH it is possible to mash at a high temperature while controlling mash pH in the normal range to have wort that is excellent for non-alcoholic beer production.

When designing a recipe for low-alcohol beers, expect to get much lower extract efficiencies from your mash than you would normally experience. Hotter mashes can see efficiencies drop to 50% or lower.

Selecting the right yeasts

With a low-maltose wort, common ale and lager beer yeasts (Saccharomyces cerevisiae and Saccharomyces pastorianus) can be used to ferment low-gravity wort to non-alcoholic beer. Keep in mind that these regular yeasts will ferment all the fermentable sugars that are available to them and, depending on your process, may result in finished products that are above 0.5% alcohol by volume. If the finished product is out of specification, it may be diluted by adding de-aerated water.

Other strains of yeast that cannot metabolize maltose may be used instead of S. cerevisiae to reduce how much alcohol is produced during fermentation. Aim to select a strain that can ferment as few sugars as possible or which ferments other sugars that will not be present in the product at any point. Many brewer’s yeast alternatives can only metabolize simple sugars such as glucose and fructose. A lot of research is still ongoing to identify Saccharomyces and non-Saccharomyces yeast species that can be used to ferment wort into low alcohol beers. We have listed just a few below.

Hanseniaspora spp.

Hanseniaspora uvarum (such as our NAY) is a wild yeast that is often found on grape skins and in wine must. It is a very versatile species that can provide pleasing flavour characteristics when fermented cold (15°C) and warm (25°C). Regardless of which temperature it is fermented at, this yeast consistently produces beers that are below the 0.5% alcohol by volume threshold that is required to be labelled non-alcoholic beer.

In small-scale experiments, two additional Hanseniaspora yeasts (H. valbyensis and H. vineae) have shown to grow in standard wort although they are unable to utilize maltose and maltotriose. Strain utilization of maltose and maltotriose (the most dominant sugars in malted barley) is a very important consideration in selecting yeasts for brewing non-alcoholic beer. Additionally, H. valbyensis and H. vineae do not produce phenolic off-flavours making them suitable for the production of non-alcoholic beer.

Saccharomycodes ludwigii

This yeast species is commonly utilized for the production of non-alcoholic beverages. It is considered a spoilage organism in the winemaking process but can be used to produce lager-like low-alcohol beers. This strain can only ferment glucose and fructose, which are typically not present in high concentrations within wort (often less than 5% of total sugars). A properly produced low-alcohol wort should see between 0.5 and 1.5°P of attenuation, resulting in beers between 0.25% and 0.80% alcohol by volume.

This strain can be used to produce lager-like beers at lower temperatures. Fermenting at a lower temperature will provide the option to utilize arrested fermentation should the beer keep fermenting more than desired.

Genetically diverse Saccharomyces cerevisiae

Genetic variability in different S. cerevisiae strains results in a unique strain diversity that can be exploited for the production of non-alcoholic beers. For instance, we found that a S. cerevisiae strain obtained from a local brewer in Ghana, West Africa poorly ferments standard wort made from barley resulting in <50% apparent attenuation.

This yeast strain is typically used for the production of pito (a traditional alcoholic beverage) made from cereals such as guinea corn (Sorghum vulgare) and millet. Traditionally, yeast cultures from a previous brew are used to repitch new batches of wort made from guinea corn or millet. Continuous repitching of the yeast for subsequent fermentations over several generations induced genetic variability which resulted in an adaptation of the yeast to utilize the sugars present in these cereals. This induced adaptation to ferment the sugars present in guinea corn and millet may partially explain why such yeasts are unable to effectively ferment sugars present in malted barley.

The poor attenuation of the Ghana yeast in wort made from barley provides an opportunity for using genetically diverse S. cerevisiae strains in brewing non-alcoholic beers. Interestingly, this strain of yeast contributes an estery and tropical fruit (banana and pineapple) flavor and aroma during fermentation of barley wort, which will be desirable for non-alcoholic beer. Further research is needed to explore the potential of genetically diverse S. cerevisiae strains for the production of non-alcoholic beers.

Escarpment Labs Strain Screening

From a large list of maltose-negative and low-attenuating yeasts, we eventually narrowed down our candidates to three species: H. uvarum, T. delbrueckii, and S. cerevisiae.

From our own R&D work, we have experimented with Saccharomyces and non-Saccharomyces yeasts to produce non-alcoholic beers. We fermented low gravity wort (OG 1.019) with H. uvarum, a wild strain of Torulaspora delbrueckii and a strain of S. cerevisiae that poorly ferments maltotriose. While all three strains produced desirable flavors and aromas, the H. uvarum strain, compared to the other strains, fermented the least sugars (see graph below) resulting in a low ABV (<0.5%).

Figure 1: Fermentation of low gravity wort by different yeasts that poorly utilize malt sugars.
Figure 2: Beer brewed with Escarpment’s H. uvarum strain (NAY) is preferred to a typical non-alcoholic beer.

Fermentation

Many of the mentioned strains may still produce by-products such as diacetyl (buttery off-flavour in beer). The use of enzyme products such as alpha acetolactate decarboxylase (ALDC) can help prevent diacetyl from being present in the finished product. When following the manufacturer’s instructions, use the higher dosing rate to help ensure that diacetyl is processed before it can become a problem.

As previously mentioned, fermenting at cooler temperatures can help control the fermentation such that it may be stopped if needed via chilling to keep the product within the low alcohol specification, for example.

Cellaring

At the end of fermentation, many of the previously mentioned strains do not reduce the finished beer pH below 4.5, which is necessary from a food safety standpoint to inhibit pathogenic bacteria. Finished product pH can be adjusted through the use of food-grade acids such as phosphoric or lactic acid. If possible, dose in-line during the transfer of the product in-between tanks to ensure the acid has been thoroughly mixed into the product. Pre-acidification of the wort prior to fermentation is also possible.

Other treatments may be taken to reduce the risk of re-fermentation in the package by utilizing chemical stabilizers, such as sorbates, benzoates, etc. Be sure to check with your local regulator to determine what labelling requirements are needed if this approach is taken.

Packaging

Care should be taken to ensure that the product is as shelf-stable as possible. A full packaging system CIP should be performed prior to packaging any non-alcoholic product. If your operation does not perform CIPs in between each brand change, consider only packaging non-alcoholic products at the start of the day when your equipment is known to be freshly cleaned.

Pasteurization is the best way to protect the product from re-fermentation, and the use of a tunnel pasteurizer can help ensure that the entire product and its container is shelf-stable.

Finally…

The success of low to no-alcohol beer production using biological methods largely depends on the mashing method, choice of yeast as well as cellaring and how the product is packaged. The sensory attributes of low alcohol beer will play a major role in making the product stand out.

Our focus is on making progress towards lower-cost methods of producing these beers. While advanced dealcoholization technologies are promising, the cost is out of reach to most brewers.

We’re excited about the future possibilities of isolating and developing a wider selection of maltose-negative yeasts that match the flavour diversity of maltose-positive yeast strains used for the production of regular beer, making it easier to produce a wide variety of great-tasting non-alcoholic beers.

Instructions and Recipe for using NAY (Non-Alcoholic Yeast)

Making non-alcoholic beers is getting easier, but there are still rules to follow. Check out our Instructions before you brew. This product is available to professional brewers only and must be pre-ordered.

References

Andrés-Iglesias, C. et al., 2015. New trends in beer flavour compound analysis. Journal of the Science of Food and Agriculture, 95(8), pp.1571–1576.

Bellut, K. et al., 2018. Application of Non-Saccharomyces Yeasts Isolated from Kombucha in the Production of Alcohol-Free Beer. Fermentation , 4(3)

Bourbon-Melo, N. et al., 2021. Use of Hanseniaspora guilliermondii and Hanseniaspora opuntiae to enhance the aromatic profile of beer in mixed-culture fermentation with Saccharomyces cerevisiae. Food microbiology, 95, p.103678.

Choi, E.J., Ahn, H.W. & Kim, W.J., 2015. Effect of α-acetolactate decarboxylase on diacetyl content of beer. Food Science and Biotechnology, 24(4), pp.1373–1380.

Gallone, B. et al., 2018. Origins, evolution, domestication and diversity of Saccharomyces beer yeasts. Current Opinion in Biotechnology, 49, pp.148–155.

Jiang, Z. et al., 2017. A novel approach for the production of a non-alcohol beer (≤0.5% abv) by a combination of limited fermentation and vacuum distillation. Journal of the Institute of Brewing, 123(4), pp.533–536

Michel, M. et al., 2016. Review: Pure non-Saccharomyces starter cultures for beer fermentation with a focus on secondary metabolites and practical applications. Journal of the Institute of Brewing, 122(4), pp.569–587.

Muller, C. et al., 2020. Processes for alcohol-free beer production: a review. Food Science and Technology, 40, pp.273–281.

QYResearch, 2019. Global Non-Alcoholic Beer Market Insights, Forecast to 2025. Available at: https://reports.valuates.com/market-reports/QYRE-Auto-10L288/global-non-alcoholic-beer

Sefa-Dedeh, S. et al., 1999. Yeasts in the traditional brewing of pito in Ghana. World Journal of Microbiology and Biotechnology, 15(5), pp.593–597.

Serra Colomer, M., Funch, B. & Forster, J., 2019. The raise of Brettanomyces yeast species for beer production. Current Opinion in Biotechnology, 56, pp.30–35.

Varela, J. & Varela, C., 2019. Microbiological strategies to produce beer and wine with reduced ethanol concentration. Current opinion in biotechnology, 56, pp.88–96.