Mariem Lamine, Paméla Nicolle, Aurélie Roland, and Karine Pedneault*
*Université du Québec en Outaouais, 78 rue Principale, Canada 
(karine.pedneault@uqo.ca)

Nordic wine regions face challenges related to seasonal climate variations, including cold nights from late August onward that may affect berry ripening, preventing the breakdown of malic acid and hampering the accumulation of aroma precursors. With climate change, large climate fluctuations during the season further contributes to variable levels of ripening in northern vineyards. In Vitis vinifera, partial grape drying and cold storage have been shown to decrease the acid content of berries and increase their concentration in aroma precursors, including thiol precursors. Enological techniques to improve berry quality are understudied in interspecific hybrid grapes. In this experiment, we evaluated the effect of postharvest processes such as cold storage (10°C) and partial grape drying at two temperatures (20 and 30°C) on the organic acid and thiol precursor content of two white (St. Pepin, Frontenac blanc) and two red (Frontenac, Marquette) Vitis sp. varieties, during 12 and 24 days. Compared to berries prior to treatment, higher temperature (20, 35°C) lowered the titratable acidity (TA) in Frontenac, but not in Marquette. In contrast, cold storage increased TA in Marquette and St. Pepin. Only the highest temperature (35°C) decreased TA in Frontenac blanc and St. Pepin.

Aroma precursors are currently being analyzed so results will be available on the poster.

Funding Support: AAFC, CGCN, MITACS