Own Cultural Yeast - an Effective Means of Achieving the Identity of Georgian Wines

Abstract

Winemaking has been the leading economic field in Georgia since time immemorial, and Saperavi is an ancient entrepreneurial grape variety, the wine made from which has high value properties: from a technological, commercial and medical point of view.

As a rule, wines made from one variety and from different places of origin should have different individuality. This regularity is violated by foreign commercial dry yeast, which was massively imported to Georgia for fermentation of grapes at the end of the last century and is still actively used today, with the help of which the individuality is absorbed and the characteristics of the wines of different origins are unified. In addition, due to the use of yeasts bought expensively with foreign currency, the cost of Georgian wines has also increased, which creates a significant problem for wine producing companies from a commercial point of view.

For the first time in the history of Georgian winemaking, a way to solve this challenge was tried in product quality-oriented "Shumi Winery": with the cooperation of scientists from Telavi State University and Free University of Brussels, for wines with three designations of origin of Saperavi - Mukuzani, Kindzmarauli, Napareuli - the dominant pure strains of Saccharomyces cerevisiae were isolated and purified from the wild yeasts present in the wine sediment fermented on natural yeast, in other words their own cultural yeasts were produced. Today, "Shumi" makes exceptionally high-quality "Mukuzani", "Kindzmarauli", "Napareuli" based on these yeasts.

In the master's scientific research, the results of which are presented in the present article, a fundamental study of the properties of wines made from the Saperavi grapes of these three microzones on their own cultural strains was conducted for the first time:

1) According to biochemical qualitative indicators;

2) According to the substances useful for health (biologically active substances, antioxidants)

3) According to the content of the substances harmful to health (radionuclides);

4) According to organoleptic characteristics;

Wines made with newly bred yeasts were compared with wines made with commercial yeasts from the same raw materials. It was established that the various qualitative indicators of wines made on own yeast are not inferior to similar indicators of wines made on foreign commercial yeast and, in some cases, are better than them.

Due to its high actuality and great importance for Georgian winemaking, the research was financed by the Shota Rustaveli National Science Foundation of Georgia.