What are tannins?

Time and again you hear wine drinkers say things like “it has a velvety tannin” or “the tannin is still quite green”.
For people who are not yet very familiar with the subject, this is often the moment when they either answer “that’s right” as confidently as possible or simply openly admit that they have no idea about tannins.
This is how it is for most people.
So it’s time to add another skill to your wine knowledge: talking about tannins.

What are tannins?

Tannins are plant-based phenolic compounds. They are found in white and red grapes, mainly in the seeds and stems. If wine is fermented on the mash, meaning the complete stem structure and not just the crushed grapes, the tannins are released along with the pigments. The level of tannin content depends on the grape variety.

Strukturformel Tannin — Tannins - Thanks to the structural formula, everything is suddenly clear!

White wines are gently pressed first, and then only the juice is fermented. This results in less tannin in the wine, making it lighter and fresher. This also explains why white wine is chilled and red wine less so. If heavy red wines with a lot of tannin are chilled, they quickly taste bitter and harsh.

How do tannins taste? How can I tell if a wine has tannins?

If you taste a red wine and after the first sip you have a velvety feeling on your tongue, that's tannin. The more astringent and bitter the mouthfeel, the "younger" the tannin. The smoother and softer the wine feels, the "riper" the tannin.

When a heavy red wine matures in the bottle over years, the small, short-chain tannin molecules connect and become longer and longer. The longer these tannin molecules become, the rounder and softer the wine tastes.

When you feel a slight pulling sensation at the back of your mouth, this is called astringency. This describes the puckering sensation in the mouth due to bitterness. Another technical term when it comes to tannins.