We store our wines in cellars for years – decades even. But do wines really improve with age? How long can you keep a wine before it starts losing quality? The answer to this question may surprise you.

First of all, which wines are meant to age? We like to believe all wines improve as they get older. And that idea makes sense: it is highly recommended to keep a wine untouched for a short period of time after it is bottled. The wine is then considered “sick”, due to the process of bottling. After this so called “Bottle Shock” period, the wine has dissolved all oxygen to which it was exposed during the bottling process and is ready to be consumed.

So how long does the Bottle Shock last? It is hard to give a concrete number of days, but a few days to a couple of weeks should be more than enough. And after that, don’t wait too long before opening the bottle! Most wines are meant to be consumed within one year (max. two years) after bottling.

But what exactly makes a wine suitable for ageing? How do you know whether a wine should age or not? The duration of a wine can be broadly divided into three phases, the first of which is the youthful phase. Young wines normally have bright colours and primary aromas. The aromas of middle-aged wines are more developed and their colours start getting a brownish shade. This change carries on through the next phase: the old age. That is when the wines get their last hint of brown, changing a red wine into a purplish tenné and giving white ones a goldish green shade.

However, the time it takes to reach the old phase differs from wine to wine. It depends on three very important key components of the wine: acid, tannin and sugar.

A high acid level means a low pH degree, which makes the wine more stable: it slows down the degree to which chemical oxidation reactions take place. These chemical reactions mature the wine and, therefore, high acid levels allow wines to age more slowly than wines with a low level. Examples of wines with a low pH are Riesling and Pinot Noir.

Tannins are polyphenolic compounds that naturally occur in wood, plants, leaves, seeds – and fruits. The tannins in grapes play a crucial part in the ageing process of wines. Basically, what they do is they protect the wine from oxygen. Oxygen accelerates a wine’s maturation, and so a high level of tannin can extend the life of a wine. Tannins are mostly found in red wines (that’s why it is usually red wines we drink at an appropriate age), but some white wines also contain tannins. Wines with a high tannin level are Tempranillo and Cabernet Sauvignon.

During the fermentation of wine, yeast cells convert sugar into alcohol. But once the beverage reaches a certain level of alcohol, the fermentation stops. A high level of sugar from then on ensures that a refermentation cannot take place. Refermentation is fatal to a wine’s life: it makes a wine age very fast. Therefore, a high level of sugar protects a wine from ageing.