Winery's own yeasts

The EU-funded project, in which several wineries in the Palatinate and a winery in the Netherlands are involved, aims to develop processes for the provision of winery-specific yeasts. At the same time, there are several fields of research for establishing molecular biological methods. First, spontaneous fermentations in the winery are sampled and the S. cerevisiae strains are isolated. Then SSR or microsatellite markers are used. These are short repetitive sequences in the genome that make it possible to create a molecular biological "fingerprint" of each strain. This technique has been successfully established at the Rural Area Service Center (DLR) Rhenish Palatinate. It is also possible to compare the pattern of a strain with the pattern of a pure yeast. This also allows a statement to be made as to whether the isolated yeasts are identical to a pure yeast. The diversity of the S. cerevisiae strains can be determined by using the molecular biological markers. Fermentations are carried out with these strains on an experimental scale. This allows the fermentation behavior to be determined for each strain. The wines from the trial fermentations are then subjected to a sensory test together with the winery using the napping method. In the end, the winery decides on a strain that will be used for the fermentations in the coming fall. The partner wineries are very satisfied with the initial results of using the winery's own yeast and wines have already been produced on a large scale.

The use of molecular biological markers to differentiate between S. cerevisiae strains and the use of the winery's own yeasts offers opportunities for numerous research projects. For example, research is being carried out into the forms of preparation, i.e. liquid yeasts or freeze-dried yeasts. In addition, the use of wineries' own yeasts is being investigated for wineries in new, fungus-resistant grape varieties (PiWis). This has already shown that the use of the winery's own yeasts in the PiWi grape variety Calardis blanc could certainly be an alternative to commercial yeast products. In addition, the winery's own yeasts were tested for the second fermentation in sparkling wine production and successfully used in a winery. It would also be an option to completely dispense with pure yeasts in sparkling wine production. In addition, the molecular biological markers are a tool that can be used to gain an insight into the diversity within the S. cerevisiae species. The number of strains in different fermentation containers was examined and general statements can be made as to whether the isolated yeasts in spontaneous fermentations are genetically identical to commercial yeast strains or not.

The project is funded by the European Union and a Dutch regional grant.