Flavonoid compositional differences of grapes among site test plantings ofcabernet franc

Anthocyanin, flavonol, and tannin compositions of Cabernet franc grapes har vested from various places in the Loire Valley (France) in 1995 and 1996 we re analyzed using HPLC methods. All data were treated by descriptive statis tical method and principal component analysis (PCA) and related to previous ly established vineyard characteristics. Sites usually yielding intense and balanced Cabernet franc wines produced grapes with higher anthocyanin cont ents and anthocyanin to tannin ratios. Among tannin constituents, tannins f rom skins, prodelphinidins, and galloylated units were particularly abundan t in grapes from lower potential vineyards. Although the anthocyanin conten t and qualitative distribution of tannins were also affected by vintage, di fferences in flavonoid composition among the sites were consistent between the two vintages studied. The effects of both growing site and vintage may be interpreted in terms of vine earliness.