Soil or geology? And what’s the difference? Some observations from the New World

Les facteurs physiques et biologiques du milieu naturel affectant la production viticole de la R.D.O. “Condado de Huelva” et quelques relations les concernant sont étudiés dans les systèmes de la production vinicole ; le bon fonctionnement du Vignoble ayant besoin par ailleurs, du concours d’autres facteurs (Reynier, 1989 ; Paneque et al., 1996, a,b).

AIM AND METHODS: Grape withering is one of the key steps in the production of the most renowned red wines of the Valpolicella area, namely Amarone and Recioto. This practice, which was already used since Roman times, entails important modifications in grape composition and in the chemical and sensorial characteristics of the corresponding wines, especially in terms of aromatic profile. The aim of this research is evaluating the aromatic evolution during grape withering of the three main varieties used in Valpolicella wines: Corvina, Corvinone and Rondinella.Samples of the three varieties were analyzed at harvest and at different stages of withering, namely10%, 20% and 30% of weight loss. Free and glycosidically bound compounds were extracted and analyzed using Gas Chromatography- Mass Spectrometry (GC-MS). RESULTS: For all the samples the data were normalized to eliminate the effect of concentration due to grape dehydration. Terpene content and evolution varied considerably in relationship to grape variety. Corvinone was richer in cyclic terpenes (including phellandrene, limonene, and cymene) and they decreased during withering.

Red wines felt as astringent and bitter generally show high content of tannins due to grape phenolic compounds’ extraction in the maceration process. Among different enological practices, mannoproteins have been shown to improve the mouthfeel of red wines (1) and the color (2,3). In this work, we evaluated the effect of mannoproteins on the mouthfeel profile of Sangiovese wines obtained by excessive tannin extraction.

Among the macromolecules of enological interest in white wines, much attention has been paid to polysaccharides.

Wine flavor results on complexes interactions of odorous components, which come from different aromatic families like esters, thiols, aldehydes, pyrazines or lactones.