Wild or Indigenous yeasts have long been talked about in winemaking since the standardisation that commercial cultured yeasts have provided. Crafters the world over let their fermentations “go wild” for both philosophical and sensory reasons with varying results. The more cynical in the trade contend that it is merely “lazy wine/cider making”. What is evident is that wild yeasts can offer high variability in product sensory characteristics. I love the idea that the indigenous yeast from the place, adds to the “sense of place in time”, borrowing from the French conception of terroir.
Employing the services of wild yeasts can be regularly problematic for a number of reasons. They are frequently made up not of one, but multiple strains, often competing and killing each other off. Or worse a weak strain that is not alcohol tolerant. What this means is that the fermentation process can stop before completion, leaving the product vulnerable to attack from a host of nasty bacteria who threaten to spoil the product. Further to this, the indigenous yeast strains can vary from year to year with no guarantee that the latest inhabitants will produce desirable residual characteristics of the previous vintage. What is rarely discussed, is the spectacular failures despite expert care, of which I’ve had my fair share. I am constantly drawn back to using wild yeasts though, as there are the spectacular triumphs, that leave me humbled to be a part of the process at all!
Please let me introduce Boris- The Siberian Marauder, Core’s very own wild yeast, or the wild yeast that has Core as his kingdom!
Boris announced his presence when I discovered that juice I had been holding at 1 deg C, had fermented completely and two other tanks were almost completely dry (all the sugar converted to alcohol) as well. In my 15 years of making wine across the world, I had never seen this. Wild yeasts were supposed to be fragile not cryophilic, hence the name. Whilst I appreciate Boris’ strength, the refinement in some of the characteristics that he offers is nothing short of charming, especially in our barrel fermented products destined for the traditional méthode of fine cider production. The restraint and balance of the resulting products excites and teases me for the time in the future when they will be drinking at their best. Until then I will busy myself as a dutiful steward in the court of King Boris.