Optimization of Mashing Parameters Used during the Conversion of Irish Wheat Grain to Spirit Alcohol

Abstract

The Irish distilling industry is rapidly expanding, diversifying its growth with an increased interest in using different grains in whiskey production. To effectively use Irish-grown wheat in distillation, the identification of cultivars that are suited to the Irish climate and provide high alcohol yields, via a quick screening test for grain alcohol yield that is consistent with Irish industry standards, is required. The current study used response surface methodology (RSM) to optimize mashing parameters, enzyme dosage rate (α-amylase and amyloglucosidase), time, temperature, and malt inclusion rate, using a hard wheat (Triticum aestivum cv. Costello). By optimizing all factors, a maximum alcohol yield (AY) of 471 LA/tonne dry weight basis was achieved, equating to previous research. The enzyme, α-amylase plays a critical part in the process, of converting starch to sugars, and 48 U/g α-amylase was used to reach maximum alcohol yield. Furthermore, an optimal protocol was evaluated on soft wheat cultivars, producing alcohol yields in the range of 483–496 LA/tonne, suggesting the applicability of this product for use across multiple varieties and grain endosperm types. In summary, an optimal alcohol yield methodology was created, with increased AY across four distinct varieties, demonstrating the possibility for Irish cultivated wheat to be used in Irish distilleries.

Keywords:

• Alcohol yield
• process optimization
• response surface methodology (RSM)
• wheat

Acknowledgments

The authors are grateful to the Irish Whiskey Industry professionals who contributed to this research.

Author contributions

Conceptualization, SM, SW, JC and DR; methodology, SM, and JB; validation, SM and JB; formal analysis, SM JB and BM; investigation, SM and BM, data curation, SM; writing—original draft preparation, SM; writing—review and editing, JB, SW, JC, and DR; supervision, DR; project administration, SW.; funding acquisition, DR, SW, and JC. All authors have read and agreed to the published version of the manuscript.

Disclosure statement

The authors declare no conflict of interest 

Additional information

Funding

This work was funded under the Department of Agricultural, Food and Marine grant number 2019R563.