You often hear people say, “errr, there is so much tannin in this wine…” What is tannin really? Is it bad to have tannins in the wine? Do we really need tannin in the wine? Can we simply take it out? Let’s examine this very important element in our wines.
How do you “feel” tannin? What does it taste like? When you swirl the wine inside your mouth, you would especially feel the tannin on the middle part of your tongue and front part of your mouth. It’s almost like something is “attacking” your gum. This is due to a chemical reaction between tannin and protein present in your saliva. It tastes very dry and astringent in your mouth. If you want to get a good taste of tannin, try drinking some black tea and focusing on the sensation in your mouth; you will feel it immediately and clearly.
Where does tannin come from?
Key source of tannin is the outer, thicker layer of the grape’s skin. Red wine has high tannin level as red wine is made via skin contact during maceration, whereas almost no tannin in white wine. The longer the time the grape juice is soaked with the skin, the higher is the tannin level in the wine. Different grape varietal has different thickness of skin, thus explaining why the grapes with thicker skins such as Cabernet Sauvignon, Nebbiolo and Syrah produce more tannic wine than Pinot Noir, Merlot, Grenache or Cabernet France. Seeds inside the berry will also release a small amount of tannin when crushed, although impact is far less than the skin contact.
To destem or not destem, this is a decision every winemaker needs to make when making the wine. Tannin is present in the stem and winemaker decides if they want to make wine from whole bunches or just from the berries. Stems are often used when making wines with varieties low in tannin such as Pinot Noir. This lends additional tannic structure, but would also absorb some color and alcohol. Thus you would notice that red wines made without stems tend to be fruitier and darker in color. It’s important not to use unripe stem, which can bring out “green” aromas and harsh, undesirable tannins.
3) Wood barrel
Wine is often aged in wood barrel. The tannin in the wood would dissolve into the wine through contact during the ageing process. On top, oak barrels used would also impact additional wood notes and flavors depending on the type of oak used. Producers would decide the percentage of new vs. used oak barrels to age the wine (new barrels tend to give out more tannins) and the size of the barrel (smaller the size, higher the wine/wood ratio thus higher tannin). Of course, ageing in oak barrel is a luxury for wines targeting lower price point. Winemakers can also add oak chips into the wines to get those tannins; only 300 grams of wood chips are required for 100 liter of wine.
Ultimately, winemakers have all the necessary techniques to determine the level of tannin they desire. Blend of grape varietals, duration of maceration, amount of stem (if at all), percentage of new wood barrel, size of barrel – all these contribute to the level of tannin in the wine.
Why is it important to have tannin in red wine? Tannins form the backbone of red wines, giving it structure and ageing potential. It creates a full-bodied and mouth-filling sensation. Tannins also function as a natural preservative, preventing oxidation and spoiling of wine during the ageing process. As wine ages, so do the tannins; the once drying and astringent young tannins would become softer, rounder and more elegant and approachable. When you get a chance, have a nice, fully mature Bordeaux or Burgundy Grand Cru and you will immediately fall in love with that sensation.
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