Wine 101: What is Wine?

More Information on Wine
3 Wines to Pair with Grilled Foods
Pairing Wines with Spicy Foods
How Green Is Your Wine?

2. Yeast
The yeast cells turn delicious, sweet grape juice into wine. They eat sugar and produce alcohol as a by-product. Many vineyards like to use indigenous yeasts—those found on the grape skins themselves—as each vintage can bring a different combination of yeast strains, which may allow for more distinctive and complex wines. Most wineries, though, use cultivated, or commercial yeasts.

There is a distinction, however: As some wineries find that a specific yeast that was indigenous to their vines produced a better than average result, the winery may begin to cultivate the yeast. Most wineries that use truly commercial yeasts use them because they are efficient and tolerant of high-alcohol environments (aka the Achilles' heel of many indigenous yeasts; it can lead to what are known as stuck, or incomplete fermentations.)

Next: Acid »