INTERACTIONS BETWEEN ETHYL-ESTERS AND AROMA COMPOUNDS IN MODEL SPIRIT SOLUTIONS

Activities of alcohols and long-chain aldehydes in 23% ethanol were found to be additive with esters, and limits of solubility were similar. Where the solubility limit was exceeded and agglomerates were formed, the composition of this second phase depended on the relative mole fractions and activity coefficients of the solutes present. In single solutions, addition of wood extract increased the activity coefficients of aldehydes and alcohols, but in model spirit solutions wood extract had little effect on either activity. Ester activities were influenced by aldehydes, alcohols, and wood extract, with short-chain aldehydes and wood extract decreasing overall activity. Consequently, the activity or headspace concentration of a hydrophobic aroma compound in an alcoholic beverage can be determined by the concentration and nature of other hydrophobic compounds present. Also, the dissolution of wood extract during maturation influences the distribution of the compound between the agglomerate phase and the solution.