What are Tannins in Wine?

If you’re a wine lover, you’ve likely heard the term ‘tannins’ thrown around in tasting notes or wine descriptions. But what exactly are tannins, and why do they matter?

Tannins play a significant role in the structure, taste, and ageing potential of wine. In this feature, we’ll break down everything you need to know about tannins – what they are, where they come from, how they influence wine, and whether they’re good or bad for you.

So, what are tannins?

Tannins are naturally occurring compounds found in plants, including grape skins, seeds, and stems. They belong to a class of chemical compounds called polyphenols, which contribute to the bitterness and astringency in wine. Tannins create that dry, puckering sensation in your mouth when you sip a bold red wine, much like the feeling you get from over-steeped tea or dark chocolate.

Tannins are crucial to a wine’s structure, giving it body and complexity while also playing a vital role in its ageing potential. Wines with higher tannins tend to age well, as tannins act as natural preservatives, helping the wine develop more nuanced flavours over time.

Where do tannins in wine come from?

Tannins in wine primarily originate from four sources:

1. Grape Skins – Red wines, which are fermented with their skins, extract tannins from the grape’s outer layer. Thicker-skinned grape varieties produce wines with higher tannins.

2. Grape Seeds – The small seeds inside grapes contain concentrated tannins, which can add bitterness if over-extracted during winemaking.

3. Grape Stems – If stems are included during fermentation (as in some whole-cluster fermentation methods), they contribute additional tannins.

4. Oak Ageing – Wines aged in oak barrels can pick up tannins from the wood, especially when new oak barrels are used. Oak tannins are generally softer and more integrated, adding to the wine’s complexity.

How do tannins affect wine?

Tannins influence a wine’s taste, texture, and ageing ability. Here’s how:

• Texture & Mouthfeel – Tannins create a drying sensation in the mouth, adding to the wine’s structure. The more tannic a wine, the more noticeable the grip and astringency.

• Bitterness & Astringency – High tannin levels can sometimes make a wine taste bitter or harsh, especially when young. However, as the wine ages, tannins soften and become more integrated.

• Ageing Potential – Wines with high tannins tend to age gracefully. Over time, tannins polymerise (combine into larger molecules), making the wine smoother and more balanced.

• Food Pairing – Tannic wines pair well with fatty or protein-rich foods, such as steak or aged cheese, because the tannins help break down fats and enhance flavours.

Which Wines Have the Highest Tannins?

Some grape varieties are naturally more tannic than others. If you enjoy bold, structured wines, you’ll want to explore these high-tannin varieties:

1. Cabernet Sauvignon – One of the most tannic wines, known for its bold structure and ageing potential.

2. Nebbiolo (e.g., Barolo & Barbaresco) – Highly tannic with intense acidity, producing wines that soften beautifully over decades.

3. Syrah/Shiraz – Can have firm tannins, especially in cooler climates like the Northern Rhone in France.

4. Malbec – Naturally tannic, but with a velvety texture that makes it approachable.

5. Petit Verdot – Often used in blends for its deep color and strong tannins.

6. Tannat – As the name suggests, this variety is extremely tannic and is the backbone of wines from Uruguay and France’s Madiran region.

7. Sangiovese (e.g., Chianti & Brunello di Montalcino) – Medium to high tannins with bright acidity, giving it strong ageing potential.

In contrast, wines with lower tannins include Pinot Noir, Gamay, Grenache, and most white wines, which have minimal tannins since they are fermented without grape skins.

Are tannins bad for you?

No, tannins are not bad for you – in fact, they have some potential health benefits. As polyphenols, tannins have antioxidant properties that may help reduce inflammation and protect cells from oxidative stress. Some studies suggest that moderate red wine consumption can support heart health due to these antioxidants.

However, some people are sensitive to tannins and may experience headaches or discomfort after drinking highly tannic wines. If this happens, try drinking wines with lower tannins or pairing tannic wines with food to soften their impact.

So there we have it, tannins are a key component of wine, contributing to its texture, structure, and longevity. Whether you enjoy bold, tannic reds or prefer smoother, softer wines, understanding tannins can help you better appreciate what’s in your glass. If you’re new to tannic wines, try pairing them with rich foods to balance their astringency and allow your palate to adjust.