The enhanced susceptibility of alcohol‐free and low alcohol beers to microbiological spoilage: implications for draught dispense

Abstract

The spoilage of six alcohol-free (AFB, ≤ 0.05% ABV) and two low alcohol beers (LAB, ≤ 1.2% ABV) was assessed by challenge testing with microflora from draught beer. Spoilage of AFB and LABs was greater (2-5 x) than two 'control' premium lager beers (4.5% ABV). Measurement of spoilage by challenge testing was reproducible irrespective of the source of draught beer microflora (public house, date, or beer style). Spoilage was correlated with the level of 'fermentables' (glucose + fructose + maltose) in the product but was also dependent on the availability of micronutrients. The addition of ethanol (2-8% ABV) to three AFBs and a LAB resulted only in a modest inhibition of spoilage (collectively 24% at 8% ABV) and, it is suggested, that the complexity of the product composition provides protection. Given the vulnerability of AFBs and LABs to spoilage and susceptibility to microorganisms that are usually supressed by ethanol, it is strongly recommended that low or alcohol-free beer styles are not offered to consumers in the on-trade by conventional long line dispense systems. It is suggested that AFB and LABs in a draught format require innovative, hygienically designed stand-alone dispense systems that remove or significantly minimise the risk of microbiological contamination, growth and associated product spoilage.

The two faces of microorganisms in traditional brewing and the implications for no- and low-alcohol beers

“…Studies assessing the susceptibility of NoLo beers to spoilage have been limited to those identifying effective pasteurisation strategies and the unsurprising observation that ethanol augments heat in killing microorganisms. Experiments using spoilage yeasts ( Quain, 2021 ), yeast spores ( Rachon et al, 2021 ), and bacteria ( Adams et al, 1989 ; L'Anthoën and Ingledew, 1996 ) have all demonstrated that microbes are more tolerant to heat when alcohol is absent. Thus, NoLo beers in final pack may necessitate enhanced levels of pasteurisation to reach commercial stability than standard beers containing alcohol.…”

“…This poses an additional level of complexity, since the quality of beer once it has left the brewery is no longer under the control of the brewer but is dictated by handling procedures at the point of dispense ( Mallett and Quain, 2019 ). A series of challenge-test studies performed by Quain (2021) demonstrated that draught beer spoilage was 2–5 times greater in NoLo lager type beer when compared to standard products at 4.5%. Interestingly, spoilage was strongly correlated with the levels of residual fermentable sugars and the availability of micronutrients in the product, rather than the absence/presence of ethanol per se .…”

“…Furthermore, given the susceptibility of NoLo beers to microbial spoilage and the liability to microorganisms that are typically inhibited by ethanol, NoLo beer products may warrant their own bespoke dispense systems in the on-trade, replacing conventional long line dispense mechanisms. Indeed, Quain (2021) recommended that brewers consider novel, hygienically designed stand-alone dispense system that limit or significantly decreases the risk of microbial contamination, growth, and associated product spoilage.…”

“…Sales of beverages in the no- or low-alcohol products are increasing and currently represent the fastest-growing sector of the global beer market, expected to grow annually and be worth $40 billion (USD) by 2032 ( Pulidindi and Ahuja, 2022 ). It should be noted that the precise definition of a no- or low-alcohol (NoLo) beer is not universal, and the defining values with respect to alcohol content vary between Europe, United States and elsewhere ( Quain, 2021 ). For the purpose of this article the terminology used will refer to UK legislation; no-alcohol (No) beers are labelled as containing ≤0.05% ABV and low-alcohol (Lo) beers ≤1.2% ABV ( GOV.UK, 2018 ).…”