Sherry Aroma. VI. Some Volatile Components of Flor Sherry of Spanish Origin. Neutral Substances

Abstract

A 20.4 liter sample of Spanish fino sherry, withdrawn from the solera (last) stage of a fractional blending system and shipped to California in 1/5-gallon bottles, was studied with respect to its neutral volatile components. The wine was extracted repeatedly with methylene chloride, the acidic components were separated from the methylene chloride extract by extraction with sodium bicarbonate solution, and the neutral components were analyzed by gas chromatography and infrared spectrometry. Gas chromatograms of extracts from two other flor sherries — one from Jerez de la Frontera and the other from California — show that essentially the same neutral components are present in each but that there are significant differences in relative amounts of these substances.

Identified in addition to the normal fusel oil alcohols were benzyl alcohol and 2-phenethyl alcohol. Nine ethyl esters of hydroxy acids were found, among which ethyl 4-hydroxybutyrate is of considerable interest because of its known physiological effects, γ-Butyrolactone, pantoyl lactone, and γ-carboethoxy-butyrolactone were identified, and infrared spectra indicate the presence of at least three more lactones. Ethyl pyroglutamate is present in moderate concentrations in the extracts.

Sensory analyses show that the two Spanish wines have very similar aromas and tastes, a similarity reflected in the gas chromatograms of their extracts. The aroma and taste of the California flor sherry differ somewhat from those of the two Spanish sherries, a difference also reflected in the gas chromatograms. Since nearly all components are present in each of the three sherries, however, if seems reasonable that the differences in aroma and taste result from differing proportions of the same substances in the three sherries.