Published in Scientific Papers. Series B, Horticulture, Vol. LXV, Issue 1
Written by George Adrian COJOCARU, Arina Oana ANTOCE
Fermentation of grape juice with various yeasts inherently leads to wines with different aromatic profiles, which get superimposed onto the varietal aroma and may or may not be well suited to the grape variety used. Determining which commercial wine yeast to use for a certain grape variety is a challenge and a risk for the winemaker, especially when working with low doses of sulphur dioxide or when the yeast was not used before in the winery. A good option to select a suitable yeast is to perform micro-vinification to compare the sensory profile of the resulted wines. The sensory analysis can then be completed by a flash GC analysis to determine the differences in the odour intensity and in the volatile profile of the wines, compared with the wine variant fermented with a classic well-known yeast. In this study 5 yeasts were compared in order to select the most suitable ones to modulate the aroma of Romanian variety 'Fetească regală’ so that the temperate climate fruits aroma, specific to this variety, is intensified. At the same time, it was important to also identify the yeasts able to minimize the oxidative aroma when the sulphur dioxide concentration used in winemaking was low. Among the yeasts used 2 were recommended for their ester producing aroma (Anchor Alchemy I and Renaissance Allegro AL-48), while the other 3 are mainly used for their ability to release thiols (Lalvin QA23, Anchor VIN7 and Renaissance TR-313). The sulphur dioxide added in all variants was only 70 mg/l in total. Sensory analysis performed 3 years after bottling showed that some, but not all, yeasts were able to produce intense fruity aroma which was well preserved. Our study shows that for 'Fetească regală’, ester releasing yeasts are more suitable to produce stable aroma, less affected by oxidation during storage under preservation with low sulphur dioxide concentrations.
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