David’s article as prepared for the Duluth News Tribune for the article which ran on 4/29/2015:
The Key Components of Wine, Part IV: Tannins
All grape juice is white. When I first learned this, very early on in my wine education, I was completely dumb struck. This was counter to everything that I had learned up to then which could be neatly summarized as: wines come in three colors, red, white and pink.
It made perfect sense to think that white wine comes from white grapes, red wine from red gapes and pink from, what else, pink grapes. This is so neat, perfect, and sensible, that it must be true. But like most things in our world, just because it sounds right and looks right, doesn’t mean it is right.
All grape juice is white and it is only through contact with the skins of the fruit that pigmentation is extracted. White grapes don’t contain much pigmentation and therefore the white grapes make white wine, actually it’s a shade of yellow, from greenish yellow to deep golden. Different red grape varieties have slightly different skin color and the thickness of the skin will vary. To extract the color the winemaker leaves the juice in a vat with the skins for an extended period of time. This is called maceration.
Maceration is the process that turns white juice into red juice. Fermentation is the process that turns juice into wine. But during maceration more than just color is extracted from the skins. Grape skins contain phenolic compounds (also known as polyphenols) which are minute molecules that can have a major impact on the sensory profile of a wine. Two of the most important polyphenols in red wine are anthocyanins and tannins. Anthocyanins give red wine its color, a range from red to purple. Tannins give red wine its signature texture or grip.
Anyone who has ever tasted a red wine will know what tannins feel like. It is that drying sensation in your mouth. You get the same sensation from drinking green tea or eating a green banana. While this sensation might make you think the wine is dry (in the world of wine, dry means “not sweet”) it is actually a tactile perception rather than a taste perception. Your senses are being fooled into thinking it’s dry because your mouth has lost all of its slippery.
When you drink red wine the tannin molecules enter your mouth and attach to the most readily available protein molecule they can find. They bind with this molecule and you swallow it along with the wine. If your mouth is empty, save for your saliva, then the saliva is the only available protein. This removes your mouth’s natural lubrication and now you notice your tongue banging around your mouth rather than sliding around smoothly. The wine isn’t actually dry. The tannins are fooling you into the perception of dryness in an un-lubricated mouth. This makes you think the wine must lack sweetness but that isn’t the case at all. What you are really feeling is your tongue and lips and they don’t feel very nice. Thank goodness for saliva.
Let’s do a little experiment. Take a sip of red wine. Notice the drying sensation on your tongue. Now eat a piece of cheese. Take another sip. Notice how the wine feels smoother, velvet like and less dry. This is because the tannin molecules have attached to the fats in the cheese rather than your saliva. Tannins clean your mouth of the sticky, greasy, fats (which taste so yummy) and refreshes your palate. This makes the wine taste better, because you no longer perceive it as dry, and it allows for you to take another bite as if it was your first, with a clean and refreshed mouth.
Try different red wines. Try lighter styles, deeper colored wines, and try them with different styles of fats, from creams, butters and cheeses, to poultry, pork, beef and sausage. The wine, and its level of tannin, will respond differently to each fat.
Now that you know what tannin does. Next time we will put all the key components of wine together: alcohol, acidity, sugar and tannin. As you learn how to understand these key components you will be able to pair any wine to any meal.
David Devere is a certified specialist of wine. He teaches wine classes mainly in the Duluth, MN area. Contact him at firstname.lastname@example.org.