By: Mackenzie Brisbois, WinemakerThe idea of selecting yeast has never appealed to me. It makes me feel like I am ‘painting by numbers’. While the end product can be beautiful, it lacks the beauty of imperfection. Great wines are not simple — the aromatics are complex, changing and opening with time, while the palate is layered, flavours are plentiful and the finish long.
One of my favourite winemaking quotes comes from Chateau Musar in Lebanon: “I once produced a wine that was technically perfect but it lacked the charms of imperfection.”
There are so many types of yeast and they can be fascinating to use, to manipulate the fermentation. Generally when we talk about wild, spontaneous or natural fermentation we describe the natural yeasts on the skins of the grapes and using these to coax out the terroir. In reality, the fermentation is often completed by a few different yeast strains present on the grapes or in the cellar.
Full disclosure: here at Trail Estate, we have had commercial yeast used in the cellar in the past so it is likely that our fermentations are a blend of various strains from both vineyard and cellar.
I describe our fermentations as natural fermentations as I do not add any packaged yeast to the juice. Winemakers may use commercial yeast because it is safe and they can more accurately determine the end product. Conversely, with a natural ferment you are never sure how things will turn out, or if you will run into problems.
Yet, even with a natural fermentation, there are still tools in the winemaking toolbox. Knowing a few things about yeast, we can make better decisions to change our juice into wine. What are some of the tricks I use to carry out these wild fermentations? For one, I use dry ice. Not only does it make your winery look like a cool science experiment, but it also protects the grapes before fermentation kicks off. The next trick is to smell and taste often. It is a rudimentary practice but it is absolutely crucial in catching any problems early. If you want to be romantic you can think of the winemaker early in the morning smelling through the fermenting tanks and wistfully raising a glass to lips. Really though, I would picture an exhausted human, dressed in sticky clothes from processinggrapes, trying to focus acutely on those few milliliters of liquid to make the crucial next choices in the wines’ life. Does the wine smell good? Is the texture developing? Is the fermentation vessel correct?
During the heart of fermentation most problems can be fixed with a bit of air. If that fails, the lees (leftover yeast cells) from one batch can be added to another. Sometimes the yeast strain in one batch is not that great. Perhaps the strain is not strong enough. Or, perhaps it is making your wine smell like vinegar. In these cases it is necessary to try and steer the fermentation in a healthier direction.
By the time fermentation completes, many different yeast strains have found their way into the wine. This results in wines with layers of complexity and ample texture. Die-hard commercial yeast users will argue that the wines will have increased faults but I think there is a fine line. A bit of fault (being a bit of volatile acidity or reduction) can create complexity in a wine. Conversely, when the fault takes over the aromatics or flavours, the wine is unpleasant. It is risky to use natural ferments because there is no guarantee of how the wine will turn out. With some careful attention and direction, beautiful wines can be crafted: wines that showcase the vintage and the vineyard, reflecting terroir.