Project number
P04000266
Project leader
Dr Francois van Jaarsveld
Institution
ARC Infruitec Nietvoorbij, Stellenbosch
Project completed
2022
EXECUTIVE SUMMARY
Objectives and Rationale
Winter fermentation reportedly results in a high thiol count and tropical-styled Sauvignon blanc. The focus of this study was to further investigate and understand the observed differences in aroma (specifically, thiol) profiles and the obtained superior quality of the winter produced wines.
Methods
Whole and macerated grapes, must and juice at the various stages during winemaking, were chilled or frozen for different storage intervals, and compared (chemically and sensorially) to unchilled/unfrozen treatments. Organoleptic evaluations, and volatile (including thiol) and standard wine analyses were performed.
Key Results
Results show that chilling and freezing temperature treatments and the wine production stage impacted the final wines’ flavour attributes and chemical (including thiol) parameters. Sensory and chemical differences between treatments were more pronounced after four months of chilling/freezing than after immediate freezing and defrosting.
Key Conclusion of Discussion
This study shows that freezing as a delayed winemaking strategy can produce new styles of Sauvignon blanc and Chenin blanc with more intense aromas. The stage during winemaking where freezing is applied is also crucial when applying delayed winemaking methods.
Take Home Message for Industry
Freezing as a delayed winemaking strategy at the appropriate stage during winemaking can produce new styles of Sauvignon blanc and Chenin blanc with more intense aromas. Winemakers can apply immediate freezing, defrosting and fermentation, however, more defined flavour expression is observed after four months.