Pre-fermentation of malt whisky wort using Lactobacillus plantarum and its influence on new-make spirit character

Distillery fermentations are non-sterile, which allow bacterial communities to flourish, typically towards the end of fermentation. The effect of beginning the bacterial fermentation at the start of fermentation was investigated. Wort was treated for 48 h using a commercial strain of Lactobacillus plantarum followed by fermentation using a distilling strain of Saccharomyces cerevisiae. The treated wash showed a substantial increase in lactic, acetic and succinic acids Sensory analysis determined that the spirit produced with bacterial treatment were significantly different (p < 0.05) and chemical analysis demonstrated an increase in the production of ethyl acetate. These results show that pre-treatment using species of Lactobacillus could be utilised to alter the quality of new-make spirit in a distillery. By using bacterial cultures present in the surroundings or raw materials, distillers could allow naturally occurring or commercially available microflora to be added thus enhancing flavour development during fermentation and producing different spirit characters.