Tannins - What Do Wine and Leather Have in Common? February 11 2015

One of the fascinating things about wine (aside from its uncanny ability to help ease us over annoying Dow Jones industrial average related unpleasantries) is its ability to change flavor and even texture as it sits in your glass.  Especially red wine.  Wine, like most foods, is a complex mixture of chemicals that change with temperature and exposure to air.  But wine has a particular class of compounds, called tannins, that almost magically transform from something that can seem harsh and unyielding to something softer and far more flavorful.

The name “tannins” is actually based on tanning hides – the same compounds help turn relatively fragile animal skins into more durable materials like leather.  They’re part of a group called phenolic compounds and are found in the skins of red wine grapes, in coffee, tea, chocolate, and in certain leaves and vegetables.  What they share is an ability to cause astringency, which is a tactile property, a sort of dry and rough feeling in your mouth, sometimes described as “puckery,” that comes when you eat certain foods.  It’s not acidity, although highly acidic foods can cause a similar sensation.  Think of drinking black coffee or a freshly-opened red wine – it feels a little rough in your mouth and almost leaves you thirsty.  That’s because of the tannins, which also contribute some bitterness to the flavor.

The tannins bind to the proteins in your otherwise slick saliva (we know we know – eew) , and join the proteins together to form larger molecules.  These larger molecules have a rougher feel to them.  They contribute to what you perceive as the substance of the wine – you may have heard some wines described as “chewy,” and that’s because the larger molecules bump into each other and slow down the movement of liquid.  The tannins, combined with the alcohol and some other components in wine, help create the impression of fullness of texture.  They also help keep the flavor of the wine going while you’re eating food, rather than the wine being swept out of your mouth by your meal.

So what happens to wine when it’s exposed to air?  Oxygen changes the tannins into compounds that are less bitter and less astringent, essentially softening them.  This allows other flavors in the wine to come through, while still making the wine seem substantial.  (You can also soften tannic foods by introducing other proteins for the tannins to bind with – this is what happens when you add milk to coffee, for example, and it seems easier to swallow than black coffee).  Other flavor components in wine also develop with exposure to oxygen, but softening the tannins allows some of the more subtle flavors to emerge and all the other flavors to assert themselves.  Aging wines in oak also helps soften tannins, both because a small amount of oxygen gets into the barrels, and also because some of the compounds found in the wood react with the tannins.

The amount of tannin people like in wine is a matter of personal preference – and what you’re serving with the wine.  So if you need another fun parlor game to add to your repertoire, begin by gathering your finest leather accessories for the complete tannin experience.  (And by “leather accessories,” we mean your Avallone handmade leather bag or wallet, so get your mind out of the gutter!)  Then you can try an experiment with two bottles of first vine wines, the Cave la Vinsobraise Diamant Noir and Emeraude.  Both wines are 60% Grenache and 40% Syrah, and both have a fair amount of tannins, mostly from the Syrah.  Open them, pour a glass of each, and taste them (with a little water and bread in between to clean the palate).  The Emeraude is aged in oak and will seem less tannic than the Diamant Noir, which is aged in concrete.  Then let them both sit in the glass for half an hour or so, swirling them for aeration a few times during the wait.  When you taste them again, you’ll find that they both are much less tannic, and some flavors that seemed muted before are now out in front.  Also, the oak now seems to affect the Emeraude differently.   Some describe the Emeraude as more elegant, perhaps because the oak reduces the tannins more.  (If both wines still seem too tannic to you, check out the everyday reds category for wines with softer tannins.)