Yeast isolation from winery

Mortimer, R.K. 1995. Genetic Investigation Yeasts isolated from spontaneous fermentation of grape musts in California and Italy. Pract. Winery and Vineyard May/June 7-10. 

Indeed, grapes are a primary source of microorganism, and many studies have shown that natural fermentation starts with those species predominant on grapes at harvest time (Fleet et ah, 2002). These can include the apiculate yeasts (Hanseniaspora uvarum and Kloeckera apicu-lata), Metschnikozvia, Candida, Pichia, Khodotorula, and Kluyveromyces. In contrast, although it is the main wine fermentation yeast, Saccharomyces have only rarely been isolated from vineyards (Martini, 1993 Martini et ah, 1996 Pretorius, 2000 Sabate et ah, 1998), since it is closely associated with the winery environment (Ciani et ah, 2004). 

Producers have adopted the use selected commercial strains of yeasts and LAB to overcome some of the problems associated with fermentation under the harsh conditions of winter. However, to achieve greater sensory individuality and enhance regional character, there is a trend by producers to select strains isolated from their local grapes and individual wineries (Bovo et al., 2005 Malacrind et al., 2005). 

I do not know of any wineries that use cultures of flor-type yeasts for the alcoholic fermentation. (Strains of yeast that have a film stage after alcoholic fermentation are called flor types.) In our winery, we are very careful to isolate the operations where the flor-type yeasts are used. We also sterilize any residues produced from the flor-type yeasts. We do not want the flor-type yeasts to become indigenous to our region since they may complicate production of table wines. 

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