EFFECT OF FERMENTATION TEMPERATURE GRADIENT AND SKIN CONTACT ON ESTER AND THIOL PRODUCTION AND TROPICAL FRUIT PERCEPTION IN CHARDONNAY WINES
Wines with tropical fruit aromas have become increasingly more available1,2. With increased availability of different wine styles, it has become important to understand the compounds that cause the fruity aromas in wine. Previous work using micro fermentations showed that fermentation temperature gradients and time on skins resulted in an increase in thiol and ester compounds post fermentation and these compounds are known to cause tropical fruit aroma in wines³. This work aimed to scale up these fermentations/operations to determine if the desired aromas could still be achieved and if there is a perceivable difference in tropical fruit aromas, liking, and emotional response in the wines at the consumer level. Four treatments were tested at varying fermentation temperature gradients and skin contact times: control fermentation at 13°C with no skin contact (SC0FG0), fermentation at 13°C with 18 hours of skin contact (SC1FG0), fermentation temperature gradient by time (20°C for 4 days then reduced to 13°C) with no skin contact (SC0FG1), fermentation temperature gradient by time with 18 hours of skin contact (SC1FG1). A change in winemaking scale did not alter the pH, residual sugar, or alcohol of the wines. Chemical analysis and descriptive sensory analysis were conducted to determine the alterations on the composition and aroma profiles of these wines. Check-all-that-apply (CATA) showed different prominent aromas for each wine treatment, with pome fruit, stone fruit, pineapple, honeysuckle, honey, and passionfruit being the most perceived aromas. Descriptive analysis (DA) showed that SC1FG0 was significantly different from both SC0FG1 and SC1FG1. SC1FG0 presented the most tropical fruit aromas, SC1FG1 presented more stone fruit, and SC0FG1 presented more honey and lemon/lime. Understanding the causes of tropical fruit aromas in wine and processes that alter these compounds is necessary to ensure winemakers can achieved tropical fruit quality consistently.
Issue: OENO Macrowine 2023
1. Department of Food Science and Technology, Oregon State University, 100 Weigand Hall, 3051 SW Campus Way Corvallis, OR 97331
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fermentation gradient, skin-contact, CATA, sensory analysis