How a microscopic yeast makes a big difference – how geographic limitations of yeast populations can determine the regional aroma of wine

Wine yeast strains Saccharomyces ellipsoideus have important applications in food industry and in this regard is sought isolation as pure cultures and selecting those strains, which in laboratory investigations which have great biotechnological properties This study was intended as the ratio of live cells and autolysates cells also the influence of culture medium on this report. Yeasts selected for this study were isolated from industrial strains of indigenous grape varieties, namely: Feteasca Royal (FR) Feteasca White (FA), black Feteasca (FN), Romanian Tamaioasa (TR), Babeasca Black (BN) and Cotnari Grasa (GC).

A misconception lingers in the minds of some wine consumers that Champagne wines don’t age. It’s largely a myth, certainly as far as the best cuvees are concerned. Actually, during the so-called autolysis period of time (in the closed bottle, after the “prise de mousse”), complex chemical reactions take place when the wine remains in contact with the dead yeast cells, which progressively bring complex and very much sought-after aromas to champagne. Nevertheless, despite their remarkable impermeability to liquid and air, caps or natural cork stoppers used to cork the bottles are not 100% hermetic with regard to gas transfers. Gas species therefore very slowly diffuse through the cap or cork stopper, along their respective inverse partial pressure. After the “prise de mousse”, because the partial pressure of CO2 in the bottleneck reaches up to 6 bars (at 12 °C), gaseous CO2 progressively diffuse from the bottle to the ambient air
(where the partial pressure of gaseous CO2 is only of order of 0,0004 bar).

Brettanomyces/Dekkera yeasts in wine are able to produce various spoilage compounds that are, at high concentration, detrimental to wine quality. The principal spoiler compounds associated with Brettanomyces spp. are vinyl and ethyl-phenols that are responsible for off- odours described as “animal”, “medicinal”, “sweaty leather”, “barnyard”, “spicy” and “clove-like”.

Many volatile compounds of different chemical/biochemical origin contribute to wine aroma. Certain key ‘varietal’ aroma compounds such as methoxypyrazines are formed in the grape and appear to be only scarcely influenced by fermentation.

Agro-ecological transition and adaptation to climate change are the two major challenges facing modern agriculture.