Posted on 16th Feb 2020
You may have heard about tannins in wine. What are they, where do they come from and what purpose do they serve?
Tannins are a phenolic compound found in the skins of a grape that actually ripen over the course of time. Ok, did your eyes just glaze over and you found yourself back in high school chemistry class? Don’t panic, we’re going to break this down.
What is the purpose of tannin? What is the purpose of life? The former is easier to answer, so we’ll go with that. Tannins have multiple roles to play in a wine, including stabilization, ability to age, complexity, and taste profile.
Tannins are molecular compounds found in the skins, stems and seeds of a wine grape. They are also found in very innocent sources such as blueberries, but I’d rather have my daily dose of tannins in a glass of wine and not in a muffin. Coffee, tea and even chocolate contain tannins. For those of you that aced chemistry, here is the molecular form:
Fact of fiction? Tannins are only found in red wine.
Tannins are primarily found in red wine, although you may run across a few errant ones in rosé wine. Red wines are fermented on their skins allowing the tannins to seep into the wine. Rosé wine is only fermented for a short time on the skins so just a few tannins sneak into the finished wine. For the vast majority of white wines, the skin is removed prior to fermentation, thus no tannins. Tannins are also found in oak barrels used to mature a wine. There are some that argue white wines aged in oak barrels contain noticeable tannins. Just nod, pretend to listen, and continue drinking your glass of red wine, full of tannin.
Is the thickness of the skin the only thing that determines tannin? Grape varietals have different skin thickness which contribute to tannin level, color and flavor. For example, Cabernet Sauvignon has a thick skin while Pinot Noir has a thinner skin. The thicker the skin, the higher the level of tannin and often the deeper color of the wine. This makes absolute sense from a pure chemical point of view. However, Mother Nature has quite a role to play. Wind, heat, hail, rain, soils and much more can affect the level of tannin. Not to forget the wine making process! There are techniques that extract more or less tannin and in some regions of the world, you can even add tannin powder. Is that cheating? Perhaps, perhaps not, it depends on who you ask and how many glasses of wine they have already consumed.
The region and “terroir” can also influence tannin. For example a red Burgundy made from Pinot Noir, may have higher tannins than a Pinot Noir from Oregon, or maybe not. There are many mysteries found in wine and if you find someone who can definitively answer the multitude of questions, then run away, fast. Nobody can know everything.
How can you detect tannins in wine? A chipmunk has all the answers.
Take a small sip of wine and hold it between your upper lip and upper gum for fifteen seconds, just like a chipmunk. Swallow the wine and notice how it makes your mouth feel. Does it suck out the moisture leaving a dry and dusty feeling in your mouth? Do you feel like there are scratchy wool sweaters on your teeth? The stronger the sensation, the higher the tannins. Tannins bind into your saliva receptacles and wick away the moisture in your mouth. They can be bitter and aggressive, perhaps a result of an incident on the playground, we will never know. To combat the tannins eat fatty or salty foods that will bind into your saliva receptacles leaving no room for the tannins.
What is that black stuff at the bottom of my bottle?
As a wine ages, the tannins link together and become heavy, falling to the bottom of the bottle and creating black sediment. The weird black stuff is thick, bitter and unfriendly, so you need to remove it. After all, nobody wants to chew on their wine. Wine should be stored on its side so the liquid is in contact with the cork. Place the bottle upright for a minimum of 24 hours prior to opening and consuming. This means you will have to think in advance about what you are going to drink! Decanting is a process of removing the tannins and is often performed in front of a candle to look sophisticated and elegant. More on decanting wine in another post.
Have something interesting to add about tannins? Let us know!