It is well known that spontaneous fermentations can sometimes deliver wines with great aromatic complexity. This is due to the fact that various yeast species take part in the fermentation, each making their unique contribution to the final wine sensory profile. However, due to the risks involved with spontaneous fermentations, many winemakers choose to inoculate their wines with commercial yeast starter cultures known for their fermentation reliability, suitability for certain wine styles and repeatability of results. These starter cultures are mostly Saccharomyces cerevisiae, commonly referred to as "the wine yeast."
In recent years wine yeast companies started to investigate the commercialization of "wild or feral" yeasts in order to reproduce the effects of spontaneous fermentations in a controlled way. Non-Saccharomyces yeasts do however require a co-inoculation with S. cerevisiae yeast to ensure fermentation reliability.
In a different approach the Institute for Wine Biotechnology, Stellenbosch University in South Africa created a hybrid wine yeast between Saccharomyces cerevisiae and Saccharomyces paradoxus – a wild yeast also associated with winemaking. S. paradoxus has the ability to partially breakdown malic acid (some strains up to 38%) as well as pectinolytic activity, two traits not normally found in S. cerevisiae yeasts.
Malic acid breakdown can assist in the biological de-acidification of wine whilst pectinolytic activity can assist in wine clarity and filterability. S. paradoxus strains have also been reported to have pleasant aromatic profiles in wines when inoculated on their own in musts. The decision was taken to use hybridization to obtain hybrids between the two species that will potentially combine the positive traits of both species. Anchor Exotics SPH proved the most suitable hybrid and has the following unique characteristics:
Interspecies hybrids (hybrids between the species of the genus Saccharomyces sensu stricto): The Saccharomyces senso stricto complex are a group of closely related species and include species such as S. cerevisiae, S. bayanus, S. paradoxus, S. cariocanus, S. kudriavzevvi and S. mikatae (Brito dos Santos et al. 2007). These species can easily hybridize in nature but produce mostly sterile offspring; meaning can only propagate asexually (Sipiczki, 2008).
Of these species, S. paradoxus is the most closely related to S. cerevisiae (Johnson et al. 2004). In 2010 Anchor Yeast commercialized the first S. cerevisiae / S. paradoxus hybrid – Anchor Exotics SPH.