Here is a shocker: White wine is made from white grapes. (There is an exception. Black grapes may be used if they’re not crushed and are pressed immediately.) After the sediment in the juice has settled, fermentation follows. The exact temperature and time varies with the style of wine being made.
First, the grapes have to be carefully taken from the vineyard to the winery. (And before that, they are carefully picked.) And, they must be taken as soon as possible after they are picked so they stay in tip-top condition.
Next, the grapes are lightly crushed for the juice, and that juice has to make contact with the yeast on the grape skins and stalks. The seeds are removed. Then, the crushed grapes are (usually) pumped into a tank called a Vinimatic. (We are not making up that name.) The grapes are squished and then steeped with their skins on for 12 to 48 hours to extract flavors and aromas that are stored in the skins.
Only the juice that runs off from the squishing machine—the vinimatic—and the juice from the first pressing is fresh and fruity enough to use for making white wine. The juice is allowed to sit while the sediment settles, and then it may be filtered.
Yeast is a catalyst for fermentation, and on the skin of a grape it converts sugar into alcohol, turning the grape juice into wine. At the end of the process, extra yeast may be added to cleansed wine for fermentation. Fermentation happens after the wine is put in stainless steel vats or oak casks. White wines are usually filtered and bottled ASAP to preserve their freshness.
Now. That delightful glass of white wine seems like a pretty good deal, doesn’t it? Enjoy!