If you love wine, give thanks to yeast. Explore the role it plays in fermentation, the risks involved and the debate over wild versus cultured yeast. WineEnthousiast tells you more.
What is yeast? What does it do?
Yeasts are single-celled fungal organisms. Without them, there would be no alcohol. Not wine, nor beer, nor any spirits distilled from various fermented carbohydrates, be they grape or grain, potato or agave, sugarcane or sap.
Yeasts love sugar. They feed upon it to live, hence their scientific name Saccharomyces, or sugar fungus. They convert sugars into alcohol, which creates carbon dioxide and heat. This is how the dough in bread rises, how malted grain turns into beer and grape must turns into wine.
There are hundreds of yeast species, and from them, countless strains. Some, like Candida, which convert sugars to gas and acids, exist in our bodies. While most yeasts are beneficial, some spoilage yeasts impair the flavor of food and drink. It was not until the 19th century that science began to understand the function of yeasts, but grain and fruit has been fermented for millennia.
Are there inherent risks to fermenting wine?