The Scoop on Tannins

You’ve probably heard the word “tannins” many a time, and if you asked what they are, you probably got a vague explanation like “it’s the thing in wine that makes your mouth feel dry and your lips pucker.”  While this is a good description of the sensation tannins cause in your mouth, it doesn’t really explain what they are or the role they play in winemaking. Here’s the scoop on these tangy taste changers.

What are tannins and where do they come from?
Tannins are phenolic compounds that cause the sharp, bitter taste found in some wines.  They are present in grape skins, stems and seeds (as well as in tea and coffee beans), and in the oak barrels that wine is stored in for the fermentation process.  Grape tannins affect our top gum and upper lip, while wood tannins (from oak barrels) are more noticeable in the back of our mouths.  Different types of grapes have varying amounts of tannins, and red grapes have more than white grapes. 

What role do tannins play in the winemaking process?
Tannins are a natural preservative. Many wines, usually reds, have to age to fully develop. The presence of tannins helps ensure that the wine won’t go bad as it ages.  And while wines with too much tannin will make your mouth feel dry, in the right amount, tannins add to the flavor, texture and structure of wine.

How do tannins evolve as wine ages?
During the aging process, tannic compounds polymerize, or group together to form large molecules. The number of tannins doesn’t change, but the larger molecules are perceived as softer to taste buds, turning the tannins from bitter to silky.  This is why wines high in tannin, such as Cabernet Sauvignon, need to be aged the longest. The color of the wine changes during the aging process, from purple or ruby to brick-red, and the flavors and aromas deepen in complexity. The more slowly wine ages, the more complex the flavors can become, which is why proper storage is important. The ideal climate for wine is cool, damp and dark, like a basement or wine cellar (55 to 65 degrees is best.)

How do tannins impact food pairing?
Tannins are attracted to protein molecules, which explains why wines high in tannin go well with red meat – pairing these wines with red meat will “calm” the taste of the tannins, allowing the other flavors in the wine to come through.  Similarly, wine and cheese are often paired together because the cheese’s fat and protein balances out tannin’s harsh flavor.