What are wine tannins?

Tannins are a naturally occurring group of ‘bitter,’ and ‘astringent’ compounds found abundantly in nature. Tannins are not harmful.

‘Bitterness’ refers to how a wine tastes, while ‘astringency’ refers to the tactile sensations it creates.

Prosecco does not have a high tannin concentration; instead, higher tannins are in red wines, black teas, and colored sodas.

Tannins give you a dry, astringent, mouth-coating feeling similar to biting into an unripe pear or plum or the mouth-drying effect when drinking wine.

Tannins are present in various plants, such as wood, bark, leaves, and fruit. When managed in tea, coffee, dark chocolate, and wine, bitterness and astringency can be enjoyable.

Tannins help define a red wine’s weight (light-bodied, medium-bodied, full-bodied) and its perceived sugar balance (sweet, semi-sweet, medium-sweet, or dry).

The texture helps describe the quality and quantity of tannins. For example, tannins are silky, plush, or velvety.

‘Grippy’ describes a wine that has a pleasant amount of tannins.

‘Green describes tannins that are slightly bitter or have unpleasant astringency.

‘Polished’ or ‘elegant’ describe tannins with a fine-grained texture, which is often noticeable but pleasant.

‘Resolved’ tannins are smooth, soft, and no longer astringent best describe mature wines.

Ask questions when you describe a wine:

Do the tannins immediately coat my mouth, or do they appear slowly?
Are the tannins integrated and gentle, or assertive and harsh?
Do the tannins dominate the wine, or do freshness and fruit match them?

The collective term ‘tannin’ applies to all phenolic compounds with one thing in common, they all bind to and separate proteins.

Human saliva is full of slippery protein. Red wine with high tannins will bind to saliva, causing the mouth to feel dry, which is why this protein-binding quality makes red wine and steak an excellent pairing – the wine’s astringent qualities counteract the fattiness of the meat.

Wine varieties such as Merlot and Sangiovese. Malbec, Cabernet Sauvignon, Nebbiolo, Mourvèdre, Tannat, Syrah, Shiraz, and Tempranillo have more tannins than other wines. In contrast, grape varieties such as Pinot Noir, Gamay, and Grenache grapes are less tannic because they have thinner grape skins.

While grape variety provides a good idea about tannin concentration in a wine, the grape’s ripeness also matters.

Plenty of white wines reach a majestic age without tannin. However, mouthfeel changes as a red wine mature.

The tannins leached into a bottle of wine are small molecules. Over time, tannins combine and form larger chains through the polymerization process.

The aging process reduces the tannins’ reactive surface area to produce what is known as a softer mouthfeel.

Some tannin chains become so long that they fall out of suspension, which creates and forms a sediment deposit in some bottles.

However, if a bottle of red wine has a harsh, bitter, and unbalanced tannic structure, then no aging will help even them out.

Some white wines undergo a short maceration period known as ‘skin contact.’ Freshly harvested grapes are crushed and left for a few hours or longer on their skins before fermentation to pull flavors out of the grape skins.

There has also been a recent rise of “orange wines,” amber-colored bottlings made from white grapes that use a vinification process with complete skin contact, like red wines. These wines have a tannic element, though not as strong as they can be in red wines.

The pressing regimen for high-quality sparkling wines is crucial because the bubbles in sparkling wines act like millions of little magnifying glasses, highlighting each aspect of the wine. Since these bubbles provide a textural element, and bottle-fermented wines also have texture from aging on yeast, additional texture from tannins usually comes across as bitter, and the bubbles exacerbate astringency.

A few dry, red sparkling wines, such as Lambrusco, or Shiraz, counteract bitterness with a bit of sweetness.