A while ago I said I was going to start a wine education series. As you may have noticed, I didn’t get very far with that idea– I think I did only one entry on malolactic fermentation. So I am recommitting myself to this effort through Education Tuesdays. Every Tuesday I will post on a topic, term, or subject that I think needs to be more talked about or better explained.
To start off the series, today’s bit is on tannins. The term tannin is used a lot when describing a wine, whether it is to talk about the mouthfeel (soft, harsh, firm, gripping, etc.) or to determine it’s aging ability. So what is a tannin?
The technical definition for a tannin is a plant-based polyphenol that binds and precipitates proteins, and is found in grapes skins, seeds and stems as well teas, and other fruits and plants. The name “tannin” is actually derived from the tanning process of animal hides. The non-technical answer is that tannins are the substance in wine that makes your mouth feel dry and if too pronounced, can provide a bitter taste. If tannins are excessive as they might be in a young wine, it feels like someone sucked all the moisture out of your mouth. If the wine has been aged, or did not have prolonged contact with the skins, the tannins will be much softer and give you what is described sometimes as a velvety feel in the mouth.
Other than the skin and seed contact that can give red wine its tannic structure, oak and other wood barrels that red wine is commonly aged in can provide some tannins as well.
I mentioned that tannins can be reduced over time with aging, and that pronounced tannins in a particular wine can relate to its ability to age well (in addition to fruit, acid and alcohol levels). So how does this work? What are the tannins doing in that bottle of wine over time?
First, the reason that the wine has better age ability with increased tannins is due to the chemical’s natural preservative effects. Second, the reason that wines taste less tannic and feel less harsh over time is that the tannins gradually polymerize (fancy word for join up) and when joined together in long chains give a much softer mouthfeel.
This was a bit of a technical description but was more in my terms, so I hope it made sense. If you have more questions about tannins or need some more clarification please shoot me an email.