Tannins are added to wine in many ways, but normally they come via aging in oak barrels or from oak chips added to fermenting wine. ... Most often, acidity is added in the form of powdered tartaric acid, which is added to the grapes before fermentation. Wine is made with grapes and the various fruit flavors we taste come from the process of making wine (and aren't blended in!). ... Let's find out what's inside a glass of wine, from the chemical compounds that give wine its unique taste, to the levels of common additives used to stabilize and preserve wine. Join us to find out more.