At concentrations below 300 mg/l, higher alcohols contribute to
the desirable complexity of wine aroma (Rapp & Mandery, 1986).
Isoamyl alcohols are the most abundant alcohols analysed in these
wines (Fig. 1). They have a ‘‘solvent’’ aroma descriptor and at high
level concentrations contribute negatively to the aroma quality of
wines. This is the case of wines from grapes treated with kresoxim-
methyl (Fig. 1b), which showed concentration for these alcohols
excessively high, over 300 mg/l. Isobutanol concentration
was below its odour threshold in all wines (40 mg/l; Guth, 1997)
(Fig. 1a). 2-Phenylethanol is the only fusel alcohol described at a
sensory level in pleasant terms (rose aroma); in some wines it
was over its odour threshold (7.5 mg/l; Etiévant, 1991) (Fig. 1c).
Regarding n-hexanol, whose concentration was over its odour