Final answer:
To make wine, grapes and yeast are combined to start fermentation, an anaerobic process where yeast converts grape sugars into alcohol and CO2. Unfiltered wine contains impurities that can enhance flavor, and winemaking has a rich history using natural and selected yeast strains.
Step-by-step explanation:
When you combine grapes and yeast, you have begun the process of making wine. Yeasts play a crucial role in winemaking by converting grape sugars into alcohol through a biological process called fermentation. This type of fermentation is anaerobic, which means it occurs in the absence of oxygen. During fermentation, grape juice's sugars are metabolized by yeast, producing alcohol and carbon dioxide as byproducts.
Unfiltered wine retains certain impurities and insoluble substances, like tartrate crystals, which can contribute to a wine's flavor and complexity. While water in nature contains impurities, the presence of minerals and other substances in the water used during the winemaking process can also affect the taste profile of the resulting wine. Thus, some winemakers favor leaving these impurities in the wine believing it enhances the overall sensory experience.
Throughout history, the fermentation of grains for beer and fruits for wine has been an integral part of human culture. The process uses wild yeasts from the environment, although it is now possible to select specific yeast strains to influence the flavor and characteristics of the wine. This ancient art is a dynamic interplay between nature's offerings and human craftsmanship.