If you use wild yeasts to vinify your wines, why do you do it, and what advantages does this approach offer? And if you strictly use commercial yeasts, why do you prefer this approach?
Manfred Krankl, Sine Qua Non (Central Coast, California). Well, that is a very complex subject for which there is no definitive or quick or catch-all answer–at least in my mind. We use both indigenous and cultured yeasts, depending on a slew of circumstances and gut feelings. Commercial yeasts are generally applied when we feel that the fermentation might be challenging, such as with very late harvested fruit: very ripe (very high sugar) fruit and/or anything else that I feel might provide a challenge to complete a fermentation or run the risk of having unwanted spoilage organisms take hold.
On the other hand, if fruit is very clean, healthy with balanced sugar, pH and acid numbers, then we’d likely ferment with indigenous yeasts. But I have no problem at all using cultured yeasts. They are no less “natural” than indigenous yeasts in my mind and I have yet to taste with anyone who could tell me which method was employed when tasting a wine. Having said all that, there is a school of thought that after a period of time the winery itself is so full of a given yeast environment that it really doesn’t matter much anyway which route one picks, as the winery environment itself dominates all. I can’t speak to that with grand authority from a scientific standpoint, but tend to agree with that thought process.
The downside—or potential downside—with indigenous or “wild” yeasts is that they are just that: WILD. We don’t know what we bring in. And thus there is a risk because one essentially flies blind. Most of the time and with the above-mentioned “right” circumstance, it works out fine and indeed can perhaps bring about extra complexity and a somewhat slower, more methodical fermentation process. But it can also produce a lot of problems and even more or less destroy the wine. Both indigenous and cultured yeasts can produce great wine. As with almost everything in wine making, it….DEPENDS, DEPENDS, DEPENDS.
Yves Cuilleron, Domaine Yves Cuilleron (Condrieu, France). I use wild yeast because I’m in a very old appellation of the crus of the Côtes du Rhône, and, for me, to have the expression of the terroir it’s very important to use the wild yeast from this terroir.
Of course, with wild yeast it’s more difficult to have a good fermentation, but for making wines of character you need to take risks.
Brian Bicknell, Mahi Wines (Marlborough, New Zealand). In terms of wild yeasts, I have now used wild/indigenous/non-inoculated/native ferments since 1992 and have had great success with them. There are a number of reasons that I use them, with the primary reason being to achieve greater interest and depth to the wines. Aligned with that is the idea of making wines that really show their place, so if you are using fruit from a particular vineyard then the next step is to use the yeast that live in that vineyard and making the wine as “hands-off” as possible, hopefully giving a truer representation of the site.
Marc Beyer, Léon Beyer (Alsace, France). At Leon Beyer, we are always using indigenous yeasts. It is only if we have some difficulty finishing the fermentation, as we do not like residual sugar, that we will eventually add some selected yeast. Eighty to ninety percent of the fermentation will have been achieved by indigenous yeasts and terroir character preserved.
Chester Osborn, d’Arenberg (McLaren Vale, Australia).With white wines we use mostly cultured yeast as this produces fresher, elegant wines with more flowery aromas and length. A small amount is wild, adding weight and complexity to these wines.
With pinot we do considerable wild yeast fermentation for extra flavor and complexity, but with all other reds we use cultured yeast. We have extensively done trials with wild yeast, but with no fertilizer in the vineyard, low pH and high-tannin fruit, and alcohols around 14%, the yeast often struggles to remove all the sugar. Delayed ferments are very detrimental to wine quality, flattening the wine, reducing fruit and leaving the wine vulnerable to spoilage organisms. For the bright expression of the fruit and mineral expression of the site, cultured yeast works best for us.
Olivier Humbrecht, Domaine Zind-Humbrecht (Alsace, France). Easy: here are the advantages of wild yeasts and the reason why I refuse to use commercial yeasts:
Multiple strains, so there are more different characteristics in the final wines and greater complexity.
Longer fermentations (less nutrients, more different yeast strains so more competition and population changes, etc.) so it is easier to keep wines on their total lees without stirring them.
Less lees, so no need for racking the wines before bottling.
And the problems with commercial yeasts include:
They all have added killer genes, so they’re alone to work in the wine: this results in reduced complexity, and the risk of development of a specific external characteristic (usually aroma).
Very fast fermentation, so it’s almost impossible to keep the wines on their total lees without stirring them (increased oxidation problems and impossible to do in large casks!).
All the wines start to look like each other.
Once installed in the cellar, they’re impossible to get rid of.
Teddy Hall, Teddy Hall Wines (Stellenbosch, South Africa). I was very keen to experiment with indigenous yeast early in my career, and did some research. Leaving barrels to start fermenting on their own, it seems that various yeast species such as Kloeckera, Hansenula, Pichia and Candida do a little relay race before Saccharomyces does its thing. Although the bulk of the fermentation almost always ended up with one of the commercial yeast strains (Saccharomyces) prevalent in the cellar, the wines did taste different. Because of potential risks involved in natural fermentation, I started off with natural (spontaneous) fermentation in only four barrels the first year. Tasting through the barrels these four barrels had more complexity and better mouth feel. The year after I doubled it eight barrels with same result. Since then all my barrel-fermented white wine is natural fermentation and I have never had problems with it. The tank-fermented wine is done with commercial yeast strains as they give you predictable flavor profile and fermentation characteristics.
Jeremy Seysses, Domaine Dujac (Burgundy, France) and Domaine de Triennes (Provence, France). We use wild yeasts for all of our fermentations at Domaine Dujac. I suppose the main reason we do it is that we have always done it and that it works well this year and I don’t see what commercial yeasts might bring to the equation that would be beneficial.
We have experience with commercial yeasts at Triennes, our Provençal estate. We have had to use them there because of fermentations that struggled to finish all the sugars. They do present the advantage of reliability and predictability. They are unquestionably a safer choice. But I do feel that safety comes at the expense of greater complexity.