The aim of this work was to determine the effect of grape gray bunch rot, caused by Botrytis cinerea, on the composition of Gewürztraminer (Vitis vinifera L.) wine. The treatments consisted of increasing percentages (in weight) of grape gray bunch rot, i.e., 0, 2.5, 5, 10, 15, and 20%. The experiment underwent six treatments and four replications. The variables evaluated were density, alcohol, total and volatile acidity, dry extract, reduced dry extract, reducing sugars, alcohol in weight/reduced dry extract ratio, ashes, alcalinity of ashes, color (I 420), total polyphenols (I 280), total N, glycerol, gluconic acid, minerals (P, K, Ca, Mg, Na, Mn, Fe, Cu, Zn, Rb, Li), volatile compounds (ethanal, ethyl acetate, methanol, propanol-1, methyl-2-propanol-1, methyl-2-buthanol-1, and methyl-3-buthanol-1). Results showed that there was a significant linear and positive effect between gray bunch rot and the following variables: density, total and volatile acidity, dry extract, reduced dry extract, reducing sugars, ashes, alkalinity of ashes, color (I 420), total polyphenols (I 280), gluconic acid, P, K, Ca, Mn, Fe, Rb, ethanal, and ethyl acetate; there was a significant linear and negative effect on alcohol, alcohol in weight/reduced dry extract ratio, methyl-2-buthanol-1, and methyl-3-buthanol-1; a quadratic effect on total N, glycerol, and methanol; and a cubic effect on Mg, Zn, Li, and propanol-1. There was no significant effect on Na, Cu, and methyl-2-propanol-1.
viticulture; enology; grape; wine; gray bunch rot; Botrytis cinerea
