Modelling Scotch Whisky Fermentations

Scotch whisky contributes nearly £5bn to the UK economy every year meaning that the maximisation of both product quality and process efficiency is imperative to the industry. With distilleries opening both across Scotland and the rest of the world at an astounding rate, the ability to innovate while still producing at a high capacity and within legislation is of great importance to distillers.
The production of all molecules responsible for flavour takes place during fermentation and so it is critical to enhance understanding of this process within a distillery. Modelling fermentation allows a distillery to use statistical process control to chart their fermentations, allowing the diagnosis of issues with fermentation. As well as determining consistency, the impact of altering parameters in the mashing and fermentation process further allows the distillery to fine tune their process and has the potential to open new flavour profiles into the final spirit.
A comparison of methodology used to model lab-based malt whisky fermentations is presented, showing the use and accuracy of novel, commercially available hydrometers which measure the density of fermenting wort online. This is then compared with methodology currently used within the industry.
Furthermore, the influence of original gravity (OG) on the fermentation model and its impact on new-make spirit quality will also be presented. Higher gravity fermentations have been postulated to produce a greater spirit output at a distillery without the capital expense of new infrastructure. Additionally, the conditions experienced by yeast at higher osmotic stress may unveil new flavour profiles in the final spirit.