What are tannins? 

Put simply, a tannin is a compound found in the skins and seeds of grapes (you’ll also find it in bark, wood, leaves, tea, dark chocolate and nuts), and you’d know them from two familiar scenarios: that drying feeling you get in your mouth from wine, and the crust that sometimes remains on an old bottle of red.

wine

red

Put less simply, tannins are part of a larger group of compounds called phenols, which are important contributors to wine colour, flavour and mouthfeel. These phenols can then join together into long chains called polyphenols, the longest of which are tannins (a subset of flavonoids, in case you were wondering). So tannins are big, in molecular terms, which is why they impact mouthfeel so much, particularly in terms of astringency (that drying sensation) and bitterness. 

Are tannins in wine a good thing?

While bitterness might not sound immediately appealing, tannins are integral to the balance of many wine styles because they help with structure and flavour. And structure and flavour are happy things, in our book. Tannins essentially act as a counter to the fruit sweetness and intensity of big reds, while adding layers of complexity (just think of all those happy little molecules having a party on your tongue!). If you must know, they’re also inhibiting your salivary lubrication by binding to the salivary proteins in your tongue. Try say salivary three times quickly.

Remind me where they come from?

As mentioned, tannins are evolved versions of the phenols in grape skins and seeds (unless you’re Alicante Bouschet, which is a freak and has high quantities in its pulp as well). Or oak, which has distinctly different types of tannin. That’s why oaked wines don’t always taste like someone just cranked the dryness up to 11, they often have very different mouthfeel to boot. Oak tannins can add to the viscosity and complexity of wines, white and red alike, as well as particular flavours like vanilla, coconut, smokiness and nuttiness. 

Alicante Bouschet

white

The winemaker has a lot to answer for too. Things like temperature, how long a wine’s kept on skins and other winemaking treatments can make big differences in phenolic extraction during and after fermentation. 

Not to mention that the other attributes of the wine, like viscosity, flavours, alcohol, acid and sugar levels all interact with how you perceive tannin. Then there are vineyard variables like terroir, vintage, vineyard layout and practices etc which all impact phenolic levels in grapes… so yes, you’ve opened a can of worms. Wriggly, deliciously bitter worms.

terroir

Do all wines have tannins?

Different grape varieties have different levels of tannin. Big reds tend to have a lot, things like shiraz, cabernet, tempranillo and nebbiolo. On the other hand, wines like pinot noir, zinfandel (aka primitivo) and barbera are pretty low on the tannin front.

You’ll notice tannins are usually associated with reds, but they’re also found in whites aged in oak barrels, thanks to tannin extraction from the wood itself. The most common example of this is chardonnay, and the fashion trends that follow the ups and downs of oak use and malolactic fermentation, which is why you’ll find everything from vibrant, unoaked Chablis to big, buttery, sunshine-in-a-bottle versions.

What do tannins taste like? 

The first thing you’ll notice when you drink a tannic wine is dryness and astringency in the front of your mouth. For a more literal comparison, have a sip of strong black tea or lick the inside of a banana skin, go on. The first thing you’ll notice when you drink a tannic wine is dryness. For a more literal comparison, have a sip of strong black tea or lick the inside of a banana skin, go on. Especially a nasty green one, just to get it drilled into your mind. That rough, dryness you’ve got going on now - that’s tannin. Obviously without any of its delicious counterparts, so take that flavour with a grain of salt (not literally). That dryness, anecdotally at least, lets the wine have more flavour without tasting like a cordial fruit bomb (alcohol and acid obviously help too). So bigger wines often have more tannin, which is why you’ll get a big mouthful of fruit flavour and be left with dry mouth afterwards.

Waiter, my mouth is too dry

There are basically three ways to counter a wine which is a bit too tannic for you. If it’s a young wine, decant it or let it age. Either of these processes oxidises the tannins or at least lets other elements come to the fore so the tannin’s not so obvious. Ageing has the added benefit of oxidising other components of the wine slowly, so they can interact and if you play your cards just right, you’ll end up opening that one bottle at its peak potential and have that glorious moment of everything in the right place. Not that you’ll really know until you open the next bottle and wish you’d opened it the year before.

But the best way is to have your big, ballsy red with a juicy, raw-as-possible bit of red meat. The fat and proteins of a good rare steak will nicely counter the tannins and acid, giving you a much fruitier and more vibrant perception of the wine in question.  

Novelty bonus fact: Apparently wine tannins resist oxidation in the body and are thus very good for your health. Therefore, wine = health. 

So eat, drink, think and be merry.

To your health!