An undesirable note called “floral taint” has been detected in red wines in North America caused by large volumes of frozen leaves and petioles [materials-other-than- grapes (MOG)] introduced during mechanical harvest and subsequent winemaking late in the season.
The responsible volatiles, we hypothesized, are primarily terpenes, norisoprenoids, and esters. The objectives were to investigate volatile compounds and their glycosidic precursors that may cause the floral taint problem, and explore threshold concentrations above which the problem might manifest itself.
All replicate fermentations (2016, 2017, 2018) were based on 40-kg of Cabernet Franc (CF) and Cabernet Sauvignon (CS). MOG treatments were (by wt): 0, 0.5%, 1%, 2% and 5% petioles, and 0, 0.25%, 0.5%, 1%, and 2% leaf blades. In 2017 and 2018, different yeast strains and harvest strategies [conventional machine harvesting (MH), Braud-New Holland Opti MH, Gregoire 8 MH, MH + optical sorting, and MH with pre-harvest leaf removal] were included in the CF treatments.
Concentrations of key odor-active compounds were quantified by GCMS with stir bar sorptive extraction.
Report presented at the SIVE OENOPPIA Awards 2019. The paper reproduced in this video-seminar was presented at the 12th edition of Enoforum (Vicenza, Italy, May 21-23, 2019).
Annual Subscription to Infowine: The subscription – to the price of € 60,00 (VAT included) – gives unlimited access for one year to all the documents published on the website, historical archive included: Click here