Co-fermentation in the Whisky industry for water sustainably and flavour development

The climate crisis will undeniably impact upon the natural resources essential to whisky production, namely water. Utilisation of high gravity brewing, or higher fermentation temperatures for whisky production to reduce water requirements, would necessitate use of yeast adapted to these conditions whilst still maintaining high ethanol yields and the production of desirable flavour compounds. Alternatively, co-fermentation (more than one yeast) using either co or sequential inoculation has been proposed as a potential strategy to achieve this.
Over 50 (conventional and non-conventional) yeast strains were selected based on desirable published fermentation characteristics and categorized via k-means clustering, based on fermentation performance under controlled conditions (4% YPD at 30°C), stress test screening (temperature and gravity) and maltose utilisation. Categories will be used to identify stress tolerant yeast and inform co-fermentation trials using a design of experiments approach with the aim of identifying co-fermentation strategies that could mitigate against predicted water shortages, as well as potentially offering unique flavour profiles.