Score plot on the first two principal components (64.4% expl. variance) computed on 6 variables (3 NIR, 2 UV–vis and 1 Nose). Samples are represented by their class symbol: BT¼Bassa Toscana, CH¼Chianti Classico, T¼test set samples (of other geographical origins). The outermost points of each class are connected by lines forming the convex hulls.