Читать книгу Wine Faults and Flaws - Keith Grainger - Страница 70

Primary aromas are those derived from grapes and are generally fruity or floral. A predominance of these on the nose normally indicates a wine that is in a youthful stage of development. Varietal aromas usually belong in this group. Many of the compounds that give varietal aromas remain largely unchanged by the fermentation process. Accordingly, the pronounced blackcurrant or cassis aromas contributing to the nose of a young Cabernet Sauvignon, the overt gooseberry characteristics of a Sauvignon Blanc or the elderflower fragrance of a young Seyval Blanc are considered as primary. Grape compounds contributing to individual varietal characteristics may include methoxypyrazines, norisoprenoids, furan derivatives, lipoxygenase pathway products, and phenylpropanoid pathway products [8]. Terpenes, both mono‐ and sesquiterpenes, are present in grapes and are contributors to primary aromas – they are largely unchanged by the fermentation process and have little impact upon secondary aromas. The concentration of monoterpenes declines as wines age, thus reducing the primary aromas. Maturation and ageing of the wine may also result in them being modified and accordingly contributing to tertiary aromas. Young wines made from grapes that have high levels of monoterpenes, such as the Muscat family, Gewürztraminer and, to a lesser extent, Riesling can have a nose that screams of primary fruit and show overt grape‐like aromas. By way of comparison, Chardonnay, a neutral variety may have less than 1 mg/l of monoterpenes, Riesling up to 4 mg/l and varieties of the Muscat family up to 6 mg/l.

It is worth noting, at this point, that the varieties we all know and love are only a few generations removed from their wild ancestors [8]. During the last 150 years, viticulturists have generally focused more and more on relatively few ‘elite’ varieties, much to the loss of aroma diversity, and possibly also disease resistance.