Levels of higher alcohols inducing aroma changes and modulating experts' preferences in wine model solutions

Background and Aims: This study aimed to identify the minimal concentration of higher alcohols (HA) (isoamyl alcohol/isobutanol) that causes readily discernible changes in aroma properties and preferences according to a group of Spanish wine experts. Methods and Results: A group of 16 Spanish wine experts carried out several series of two-alternative forced-choice sensory tests on three wine models (WMs) with specific aroma properties (fruity, woody and animal). Control WMs were contrasted to samples containing an increasing concentration of HA. Levels of 299 and 288mg/L of HA were able to confer their spirit-like characteristic aroma to fruity and woody-like WMs and to suppress red fruit (299mg/L) and woody (281mg/L) attributes, respectively. A concentration of 365 and 375mg/L of HA increased the animal aroma generated by ethyl phenols and the spirit-like nuances of HA, respectively. The presence of HA at a concentration ranging from 284 to 358mg/L caused a decrease in the preference. In woody WMs, highly sensitive participants were able to detect and perceive as negative an addition of HA as little as 17 and 22mg/L. Conclusions: This is the first work estimating the concentration of HA able to affect aroma properties and hedonic character of red wines. Significance of the Study: These results can assist while making decisions mainly during the fermentation stage to control HA production.