Flavors in Malt Whisky: A Review
Akira Wanikawa
Abstract
Malt whisky is made from malted barley, yeast and water, and contains volatile and non-volatile flavor compounds derived from both the raw materials and the production processes including malting, mashing, fermentation, distillation and maturation. Evaluation of the character attributes of malt whisky has mainly relied on sensory analysis and the relationships between sensory and chemical analyses are not well elucidated. Sensory analysis can outline the character and origin of flavor compounds in each process. Phenolic compounds are produced during the kilning of malted barley. Yeast and naturally occurring lactic acid bacteria affect the character during the fermentation process. Distillation in copper pot stills influences the behavior of sulfur compounds including polysulfides. Lastly, the role of maturation in oak casks involves the extraction and absorption of various compounds. Sweet volatiles and gustatory non-volatiles are extracted, while unpleasant sulfur compounds are absorbed. This review summarizes current data on the mechanisms underlying the formation of flavor compounds in malt whisky.