When it comes to winemaking, yeast is the unsung hero that transforms grape juice into the intoxicating nectar we all adore. There are two primary types of yeasts commonly employed in winemaking: wild yeasts and commercial yeasts. Each brings its unique characteristics and challenges to the fermentation process. Let's delve into what sets these yeasts apart and how they impact the final product.
What is Yeast, Anyway?
Before we get into the specifics, let's briefly touch on yeast.
Yeast is a single-celled microorganism from the fungi kingdom. It consumes the sugars in grape juice and converts them into alcohol and carbon dioxide through fermentation.
This not only gives the wine its alcoholic content but also contributes to its flavour, aroma, and overall character. What is, then, the difference between wild yeast and commercial yeast?
Wild Yeast: The Unpredictable Naturalist
As the name suggests, wild yeasts occur naturally in the vineyard and winery environment. They can be found on grape skins, in the air, and even in the wooden barrels used for ageing wine. They introduce an element of terroir into the wine, giving it a sense of place.
Fermentation with wild yeasts is often called "spontaneous fermentation" because the winemaker does not add specific yeast strains to initiate the fermentation process.
Using wild yeast can be an exciting and unpredictable choice. Each vineyard and winery has its own unique blend of wild yeast strains, which can contribute to a wide range of flavours and aromas in the finished wine. Some winemakers believe that wild yeast adds a sense of terroir or reflects the specific geographic and environmental conditions in which the grapes were grown.
Regardless, there are challenges associated with using wild yeast. It is less predictable than commercial yeast, as fermentation can take longer to start and may be less vigorous. There is also a higher risk of spoilage or the development of off-flavours, as wild yeast strains vary in their abilities to produce desirable flavours and aromas. Nonetheless, for some winemakers, the rewards of using wild yeast outweigh the risks.
Commercial Yeast: The Dependable Specialist
Commercial yeasts, on the other hand, are cultivated strains that are specifically produced for winemaking. Unlike wild yeasts, they are selected for their ability to ferment grape juice efficiently and consistently. Winemakers have more control over the fermentation process, as they can choose from a wide range of yeast strains that produce specific flavour profiles.
Using commercial yeast ensures a predictable fermentation, with a faster start and more vigorous activity. This can be particularly beneficial in regions with challenging climate conditions or when working with delicate grape varieties. Commercial yeasts also have a lower risk of producing off-flavours or spoilage, as the strains used are carefully selected and tested for their performance.
Though, some winemakers argue that using commercial yeast can result in wines that lack complexity and uniqueness. They believe that the use of wild yeast allows the true expression of the grapes and the local environment. It is worth noting that many winemakers employ a combination of wild and commercial yeast to strike a balance between consistency and individuality.
A Middle Ground: Spontaneous Fermentation
Some winemakers opt for a hybrid approach, known as spontaneous fermentation, in which they initiate fermentation with wild yeast but allow commercial yeast to take over if necessary. This can offer a balance between the complexity of wild yeast and the reliability of commercial yeast.
Which One to Choose? A Matter of Personal Preference
The choice between wild yeast and commercial yeast in winemaking is a matter of personal preference and winemaking philosophy. Wild yeast offers unpredictability and a sense of terroir but with higher risks of off-flavours and longer fermentation times. Commercial yeast provides consistency and control but may result in wines that lack complexity and uniqueness.
Ultimately, the decision should be based on the specific goals of the winemaker and the desired characteristics of the final wine. Whether wild or commercial, yeast undoubtedly plays a pivotal role in shaping the flavours and aromas that make each bottle of wine a distinct and enjoyable experience.
Cheers! 🍷