The Science of Ageing: How Time Transforms Vintage Wine

The idea of ageing a wine is an integral part of the joy of collecting and enjoying wine for scores of oenophiles the world over. In this article we’ll explore the factors behind this ageing process, including what precisely happens to the wine over time and look into how and why some wines improve with age. We’ll discover how time can impart both depth and character and turn fantastic young wines into exceptional vintages.

How Does a Wine Age?

Wine is a mixture of acids and proteins that can react with each other and change throughout its time in the bottle. It is a complex process that’s influenced by several factors but ultimately can transform the wine’s flavour, aroma, and texture.

Youthful wines contain what are known as primary flavours. These are flavours from the grapes and manifest as fresh fruit and floral notes. They can also contain secondary flavours which are added through processes in the winery, such as sweet spices from oak ageing.

As the wine ages, these flavours evolve as key components such as tannins, acids, sugars, and phenolic compounds interact in the bottle, leading to gradual changes. The tannins, primarily found in red wines, soften with age, reducing bitterness and contributing to a smoother mouthfeel. The acidity in the wine also stabilises, balancing the wine’s overall profile. This also affects the colour of the wine, as the fresh, vibrant, deep colours of youth give way to lighter garnet shades in red wines and deeper, luxurious gold and brown in white wines.

What Happens to The Flavours of Wines as They Age?

During ageing, those initial primary fruit and floral flavours from the grape shift to become tertiary aromas due to chemical reactions within the bottle. This development brings with it layers of complexity, such as earthy, nutty, and spicy notes in white wines, and dried fruit, tobacco and leather in reds.

The secondary flavours are added to the wine from the fermentation and ageing process, including vanilla, toast, liquorice, and caramel, particularly in wines aged in oak barrels. These secondary notes develop and are enhanced by the ageing process, becoming more integrated in the balance of the wine’s flavour with time in the bottle.

A well-aged wine, with a blend of primary, secondary and tertiary notes, can reflect not only the passage of time, but also the winemaker’s skill and the terroir they work with.

What Are the Perfect Conditions for a Wine to Age?

The storage environment plays a crucial role in allowing for the desired chemical reactions. These include cool, consistent temperatures, adequate humidity, and minimal light to prevent spoilage and unwanted oxidation.

In terms of temperature, consistency is the key. A consistent, cool temperature, ideally 13-15°C, gives the wine every chance to age gracefully. Large fluctuations in temperature, however, can accelerate spoilage and disrupt that ageing process. Humidity levels, too, should be kept as consistent as possible, at around 70%, to prevent corks from drying out and allow air to seep into the bottle, which could oxidise the wine. This is also why bottles are stored horizontally, to keep the corks moistened with wine.

Read our blog post “The Best Ways to Store Your Wine” for more wine storage insight!

A small amount of oxygen is beneficial. This is present in both the small amount of ullage (trapped air) in the bottle and through the cork that allows for a small amount of oxygen exchange over time. Too much oxygen, however, or exposure to reactive UV light, can degrade the wine’s compounds, leading to premature ageing and spoilage.

For anyone looking to buy older vintages, it’s important that you know how the bottles have been kept since leaving the winery to ensure you get the best quality experience possible. The best bet is to only buy from a trusted team of wine professionals!

When Should You Drink Your Ageing Wines?

This is a very difficult question to answer and depends on several factors, including the wine’s varietal, vintage, and storage conditions.

Generally, red wines with robust tannins and high acidity benefit from ageing, softening and integrating over time. For example, the likes of quality Bordeaux blends, Burgundies, and Barolos can improve with several years in the bottle. White wines with high acidity, such as Riesling and Chardonnay, can also develop complexity with age, with tertiary honeyed, nutty, or mineral notes, although again the storage conditions these wines have been subject to will have made a big difference.

There is also a matter of personal taste. Just because a wine can age, doesn’t mean you need to. Some drinkers prefer primary fruit flavours to tertiary, and so will naturally drink their wines earlier than those who enjoy the earthy, aged notes.

The only way to be certain is to taste the wines periodically. We would always suggest buying at least a case of wines you intend to age so that you can open a bottle every few months or years to track its progress. Tools such as a Coravin can do this more regularly without having the open the bottle at all!

Are All Wines Suitable for Ageing?

Simple answer, no. Not all wines are designed for ageing and that’s ok. In fact, the vast majority of wines are made to be consumed within a year of leaving the winery. It doesn’t mean that they’re not perfectly enjoyable. Delicate white wines and light-bodied reds are typically enjoyed in their youth to preserve fresh, fruity characteristics. That’s what they’re designed for and would lose their vibrancy if stored for too long.

Those looking for wines that are suitable for ageing, however, need to think about the structure of the wine. Wines with high acidity, good flavour concentration and ripe tannic structure (for reds at least) have got every chance to age very well. Add that to the wine’s varietal, vintage reports, and production methods and you can start to build a fuller picture of its aging potential for cellaring and long-term enjoyment.

Our collection of library vintage wines

This Blog post is written by Mike Turner
Freelance wine writer, presenter and judge

Mike is a regular contributor for The Buyer magazine and is a certified educator and ambassador for Bordeaux, Rioja, Ribera Del Duero, Barolo and Barbaresco, running trade and consumer events across the UK from his base in the East Midlands.

Next on our expert advice series: The Best Ways to Store Your Wine