Flavour of Spirit Drinks Raw Materials, Fermentation, Distillation, and Ageing

Aroma compounds in distilled spirits and liqueurs, their levels, odour attributes, and thresholds are most important for quality and authenticity. Using gas chromatography and mass spectrometry, especially the composition of volatile aroma compounds in distilled spirits has been widely investigated [4-8]. By direct injection of an alcoholic distillate it is possible to determine more than 50 components within levels between 0.1 and 1,000 mg L b special methods of extraction can be used to increase this number up to more than 1,000 volatile substances [6]. However, sensory analysis is still indispensable to describe and evaluate spirit drinks. 

The following review focuses on the composition of flavour compounds in spirit drinks, their origin, and their sensory attributes like odour quality and threshold value. Important information on flavour-related aspects of technology, like distillation and ageing, as well as the main categories and brands of spirits to be found on the national and international markets are summarised. Finally, aspects of sustainability in the production of distilled spirits are discussed. 

Some of the volatile substances which are produced during fermentation, like acrolein, diacetyl, 2-butanol, allyl alcohol, or acetic acid, are a result of enhanced microbiological activities and may cause an unpleasant flavour (off-flavour) at certain levels thus, elevated concentrations of such compounds are markers for spoilage of the raw material, negative microbiological influences during or after the fermentation process, or a poor distillation technique. 

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Flavour of Spirit Drinks Raw Materials, Fermentation, Distillation, and Ageing... 

N. Christoph C. Bauer-Christoph, Flavour of Spirit Drinks Raw Materials, Fermentation, Distillation, and Ageing. In Flavours and Fragrances Chemistry, Bioprocessing and Sustainability, R. G. Berger, Ed. Springer-Verlag Berlin, 2007 pp 219-239. 

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