What are wine tannins, and how do they affect wine?

Ever heard people talk about “tannins” in wine and wondered what they mean?

Tannins are significant for wine flavour, especially in red wines. They give wine its fullness, structure and feel in your mouth, and help determine how long a wine can be kept.

Read on for a breakdown of everything you need to know about tannins when choosing the perfect wine for your tastes.

Discover our full range of premium red wines.

What are tannins in wine?

Tannins are natural compounds found in plants, including fruits, vegetables, tea, coffee and chocolate. Known as polyphenols, these compounds act as a plant’s natural defence mechanism against threats like bacteria, fungi and insects.

In wine, tannins mostly come from grape skins, seeds and stems. They create that dry, bitter feeling in your mouth when you drink wine.

Different wines have different amounts of tannins, depending on the grape variety and the production process.

Red wines have the most tannins because the grape skins and seeds are left to soak with the juice (a process known as maceration) for a long time. In contrast, white wines have lower tannin levels because they are typically produced from grape juice alone.

Rosé and orange wines have some tannins from brief contact with grape skins, but they still have fewer tannins than red wines.

Ageing wine in oak barrels can add more tannins, enhancing its complexity and overall character.

Why do some wines have more tannins than others?

Several things affect how many tannins end up in wine:

• Harvest timing – Early-picked grapes may have harsher, more astringent tannins, while those harvested later tend to have softer tannins.

• Grape variety – Thick-skinned grapes have more tannins than thin-skinned grapes, such as Pinot Noir.

• Climate – Warm regions like Australia’s Barossa Valley or McLaren Vale produce grapes that fully ripen, resulting in higher tannin levels. Grapes grown in cooler climates, such as Tasmania, ripen more slowly and generally have fewer tannins.

• Winemaking techniques – If the grape skins, seeds and stems remain in contact with the juice for long periods, the tannin levels increase. Ageing in oak barrels leads to additional tannins in the wine.

High-tannin red wines

Some red wine varieties known for their high tannin levels include:

• Shiraz – Full-bodied with firm tannins, especially Shiraz wines from Barossa Valley and McLaren Vale. The wine often mellows with oak ageing.

• Cabernet Sauvignon – Loved for its velvety texture and deep, full-bodied flavour, Cabernet Sauvignon from Coonawarra and Margaret River can be particularly tannic.

• Durif/Petite Sirah – Known for its intense tannins and deep colour, Durif has a bold and robust structure.

• Sangiovese – Sangiovese features firm tannins and excellent ageing potential. It’s increasingly cultivated in Australia for its balance and complexity.

Low-tannin red wines

Here are a few low-tannin red wines:

• Grenache – Known for its relatively low tannin content, Grenache is a softer red with a smooth and fruit-forward profile.

• Merlot – With its smooth and supple texture, Merlot typically has lower tannin levels than more robust red wines.

• Tempranillo – While it can vary, home-grown Tempranillo often leans towards a softer tannin profile.

• Montepulciano – This variety often features moderate to low tannin levels. Montepulciano can be smooth and approachable with fruity and soft characteristics.

Do white wines have tannins?

Yes, some white wines have tannins, but this is down to winemaking techniques rather than nature.

Oak barrel-aged white wines, such as an oaked Chardonnay or Viognier, can pick up tannins from the barrels.