Title: The Fungi, the Ketones and the Washback: The influence of distillery microflora on whisky flavour

The fermentation, distillation and maturation stages of Scotch whisky production influence the presence of flavour-active compounds which give each whisky its distinct flavour. Unlike brewery fermentations, whisky fermentations are not sterile, allowing microflora from raw materials and the environment to enter the wash. The natural microbiological flora present within the distillery and raw materials have been widely studied, but a number of questions still remain. One question yet to be addressed is the influence of wood versus stainless steel washbacks in Scotch whisky fermentations. It is thought that the microbiological flora within wooden washbacks is responsible for an increase in the levels of particular congeners in whisky, more specifically, the presence of methyl ketones which may yield ‘sour’ and ‘fatty’ flavours. Using traditional culture methods and next generation sequencing technologies, we will investigate the microbiological flora present in within a range of Scottish whisky distilleries and subsequently explore the production of specific flavour-active methyl ketones by these microbes.