Nature and origins of sensory character in Scotch whisky
Scotch whisky production is central to the local economy, with an interesting history, and dominates international markets for brown spirit products. Researchers have characterised whisky congener compositions, behaviour and the nature of wood maturation of whisky. However there remain difficulties in understanding the nature and origins of sensory character in Scotch whiskies, a central issue being development of a consistent flavour terminology. A key aim was revision of the Scotch whisky flavour wheel, to optimise sensory analysis and training of assessors in the distilling industries, and for consumer studies. The nature of flavour perception in Scotch whisky was then explored, investigating flavour terms currently in use among industrial sensory assessors. This language was revised using standard reference compounds in 23% abv grain whisky to anchor individual flavour attributes. The wheel incorporates only positive attributes to meet current needs for interaction between sen sory, marketing and technical professionals. Concepts of flavour sensation and perception were reviewed with a separation into the reductionist and consideration of the holistic nature of perception. Sensation and perception are from different levels of human reliance, microscopic and macroscopic. The former is important in sensory assessment and the latter, in understanding consumer choice. Flavour thresholds and 95% recognition for standard flavour reference compounds were established in 23% grain spirit. The relationships between attribute weighting and product category in blends was explored using 40 retailed blends of four categories - Deluxe, Standard, Retailer and West Highland. Relationships between product category and headspace concentration of important congeners from solid phase micro-extraction (SPME) were explored to clarify the basis of discrimination.