Abstract
A study was conducted to determine the key environmental and viticultural variables affecting the concentration of 3-isobutyl-2-methoxypyrazine (IBMP) in Cabernet franc grapes. Berries were sampled from individual vines at 30 days after anthesis (DAA), 50 DAA, and harvest from ten and eight commercial New York State vineyards in 2008 and 2009, respectively. IBMP concentrations at 50 DAA were significantly higher in the warmer 2008 growing season (2008 range = 103 to 239 pg/g; 2009 range = 12 to 87 pg/g). However, in the cooler 2009 growing season a smaller percent decrease in IBMP during the period from 50 DAA to harvest was observed, so that IBMP at harvest was not significantly different between years (2008 range = 1 to 13 pg/g; 2009 range = 5 to 14 pg/g). IBMP accumulation up to 50 DAA and log-fold decrease of IBMP from 50 DAA to harvest was modeled as a function of >120 viticultural and environmental variables (122 in 2008 and 140 in 2009). Important variables identified for modeling IBMP at 50 DAA were those associated with vine vigor, which was positively correlated with IBMP accumulation. Cluster light exposure did not explain differences in IBMP accumulation across sites, but it was important for modeling smaller differences within some sites. IBMP decrease could not be satisfactorily modeled across multiple sites, but within sites, the decrease was most consistently correlated with classic fruit maturity indices (total soluble solids (TSS), TSS*pH2). The intensity of herbaceous aromas in wines produced from each site was not correlated with IBMP concentration, but multivariate models indicated that lower vine water status was the best predictor of increased herbaceousness.
Sign in for ASEV members
ASEV Members, please sign in at ASEV to access the journal online.
Sign in for Institutional and Non-member Subscribers
Log in using your username and password
Pay Per Article - You may access this article (from the computer you are currently using) for 2 day for US$10.00
Regain Access - You can regain access to a recent Pay per Article purchase if your access period has not yet expired.