Comparison of laboratory scale bourbon whiskey mashing and fermentation to pilot scale

Why the work was done: Laboratory scale methods are useful for optimising grain spirit production. While small scale methods exist, comparisons between conventional, simultaneous saccharification and fermentation, and distillery scale production are lacking. Further, there is limited understanding of how these methods affect the rheological properties of the mash and flavour compounds from fermentation. This study compared conventional and simultaneous saccharification and fermentation mashing methods to a pilot scale distillery to establish a standard laboratory method for simulating industrial bourbon production.

How the work was done: Two bourbon whiskey mashing methods were compared: simultaneous saccharification and fermentation versus conventional mashing with a dedicated saccharification step. Laboratory scale (0.4 L) and pilot scale (1663 L) fermentations were compared. Analysis focused on mash rheological profiles, sugar composition, fermentation dynamics, and volatile flavour congeners.

What are the main findings: Ethanol yields from the laboratory and distillery methods were comparable. Simultaneous saccharification and fermentation offered advantages: lower lactic acid levels, lower viscosity during cooking, faster fermentation, and a flavour congener profile almost identical to that from the pilot distillery. While simultaneous saccharification and fermentation produced a sugar profile with higher glucose levels, total sugar concentrations were comparable using all approaches.

Why is the work important: This work provides insight into the use of laboratory scale methods for studying and optimising bourbon production. The findings demonstrate that simultaneous saccharification and fermentation, with lower complexity and process time, reliably reflect industrial scale processes, including ethanol yield and flavour compound profile. Accordingly, simultaneous saccharification and fermentation provides a reliable tool for optimising bourbon production parameters and investigating flavour development.