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. © 2021 The Institute of Brewing & Distilling