The effect of storage on some characteristics of yeasts used for sparkling wines

Abstract

Abstract Yeasts Saccharomyces cerevisiae (oviformis) strain Varna‐1 were stored for 4 years in base wine with 23 gl‐1 sugar (fermentation blend) at 15°C, in grape juice at room temperature and in a lyophilised state at 5°C. In the first two cases the yeasts were reinoculated in fresh medium every 3 months. After the storage, the three cultures were activated by two‐fold consecutive inoculation in grape juice after which their reproduction in fermentation blend, their fermentation activity during the secondary fermentation, the chemical composition and organoleptic qualities of the sparkling wines obtained were investigated. It was established that the yeast storage in the fermentation blend and in the grape juice decreased the reproduction abilities of the yeasts but to different extents, while such a change was not observed with lyophilised yeasts. A more intensive secondary fermentation at the initial stage was carried out by the yeasts stored in a lyophilised state and at the end of the process by those stored in a fermentation blend. When carrying out the secondary fermentation with yeasts stored in a lyophilised state the total amount of amino acids in sparkling wines is 21.9% less as compared to the initial base wine, while with the other two cultures the decrease was not substantial. Sensory preference was given to the sparkling wine produced by the yeasts stored in grape juice.