Day 1: Tuesday, May 4th, 2021 – 10:20 am
Influence of yeast strains and fermentation parameters on Sauvignon Blanc aromatic profiles
The study of the strain (A) in comparison with a IRC7S/IRC7S strain(B) showing a high acetate ester production capability through different fermentation temperature and nutrition regimes was performed. It clearly highlighted a higher release of thiols as well as a lower concentration of acetate esters at high temperature (i.e. 18°C vs 12°C) and confirmed the importance of the Nitrogen Catabolite Repression regulation system in yeast. The supply of ammonium at yeast inoculation indeed drastically lowered and even blocked the release of 4-MMP by the strain A when the initial temperature was 18°C then lowered to 12°C after 3 days. This latter temperature regime was rated among the best ones as minimizing defects and maximizing the concentrations of most of the aromatic compounds what was judged very positively during a preliminary tasting. Strain A was then produced and dried through the E2U™ process and its viability and population were evaluated under very different rehydration conditions interms of media and stirring regimes. It showed a high resistance in all circumstances. Finally, 32 field trials in 6 different countries completed the characterization of this strain and confirmed its suitability for thiolic varieties with complex fruity notes (especially towards exotic, citrus and white fruits), a high crispness and overall good balance and persistence in mouth.