Opening a bottle of wine at its perfect moment, when acid and fruit are precisely balanced, the oak elegantly integrated and the aromas and flavours have opened up is a rare privilege. The path to perfection is not the same for all wines, some wines will develop positive characteristics as they age, and some will deteriorate. Some wines might take decades to hit that sweet spot, others get there more quickly. And of course, that moment when everything comes together will vary depending on the taster. With some knowledge, and experience, and by training your palate, it is possible to predict the development of a wine. Changes depend on the grape variety, where the grapes were grown, and the wine style, in white wines, particularly sweetness levels and acidity.

Let’s examine the changes that can occur as a white wine develops …

• Colour

As a wine develops, it changes colour. Typically, white wine moves from pale lemon to deep gold and onto amber or brown if very old. This is due to the effect of oxidation, rust and the browning that occurs on a cut apple are other examples of oxidation reactions.

• aroma and flavour

The wine’s aromas and flavours change. A youthful wine will exhibit fresh fruit aromas, lemon, green apple, pineapple, and peach for example. These are described as primary aromas. As the wine ages, multiple complex chemical reactions occur changing the composition of the wine’s 400 or so organic compounds, which include alcohols, acids, phenols, aldehydes and lactones. The organic compounds that came from the grape and were created during the winemaking process are transformed into new volatile organic compounds, such as phenylacetaldehyde which has an aroma of honey, sotolon smells of roasted nuts and toast and furfural smells like caramel.

Collectively these are referred to as tertiary aromas and flavours.

If most of the aromas and flavours in the wine are primary but there are some tertiary aromas, the wine could be described as developing.

The development of tertiary aromas and flavours can be extremely positive, bringing increased complexity and enjoyment. When a wine hits that sweet spot where there are still primary aromas and flavours but there are additional aromas and flavours from ageing, this can be a gratifying experience.

The evolution of tertiary aromas and flavours is not always positive. When the tertiary aromas start to dominate, the wine can be described as fully-developed. When phenols oxidise they can become bitter and unpleasant, the wine can lose its freshness and vigour, and it becomes tired or past its best.

Understanding the influences on the development of a wine …

• wine style

The vast majority of wines are not suitable for ageing and should be drunk immediately. For example, an IGP Veneto Pinot Grigio or most Marlborough Sauvignon Blancs are supposed to be fresh and fruity and tertiary aromas and flavours do not suit these wines, and would most likely result in a negative tasting experience.

• storage conditions

Oxidative reactions (liquid - oxygen) occur whilst the wine is in the barrel, and reductive reactions (liquid - liquid) occur whilst the wine is in the bottle. Some oxidative ageing can occur in the bottle, as there is always a little oxygen dissolved in the wine and in the headspace. Also, oxygen can enter the bottle through the closure, more through a natural cork than a screw cap. They are most noticeable in wine that has been asked in barrel and bottle for two years, and they become more pronounced the longer the wine is aged.

• Grape Variety

Some grape varieties will produce wines that are better for ageing than others. Chardonnay is well-known for its ability to age positively. The wine pictured is the 2016 Chardonnay from Red Hook Winery, located in the Finger Lakes, USA (the picture was taken in 2023). It was fermented in open-topped fermenters and it spent approximately 2 years in large neutral barrels before bottling, so there was an extended opportunity for oxidative reactions to occur. In its youth, it was most likely a medium lemon colour with lemon, sweet apple and peach notes. Now it is a deep golden colour and pronounced aromas of dried peach, dried apricot, honey, and ginger, have developed. The dominance of the tertiary aromas and flavours indicated that it was fully developed and not suitable for further ageing. It was the last bottle I had, so I’m glad I opened it and was able to enjoy it before it became too dried out and the savoury aromas and flavours of hay, nuts, and mushroom notes overwhelmed the fruit aromas and flavours. This wine was only seven years old, but another example of Chardonnay, that went through less oxidative winemaking processes, might last 10 or 15 years in a bottle.

The more aroma and flavour a wine has in its youth, the more potential it will have for the chemical reactions that result in the tertiary aromas and flavours. Chardonnay is well known for producing wines with an intense concentration of flavour which is why it can age positively. Similarly, Viura, responsible for the white wines of Rioja, and Viognier, the grape variety used in the Rhone to make Condrieu produce concentrated wines that develop positive aromas and flavours as they mature.

• Acidity

Acidity acts as a preservative, slowing the rate of oxidation. This allows more time for the development of more positive aromas and flavours. As the wine ages, acidity reduces, it becomes more integrated and the wine can take on a richer, creamier mouthfeel which can also be very attractive. Riesling is known for having a very high acidity and as such it can age considerably longer than Chardonnay, 30-50 years without a problem. Recently, I had the privilege of tasting a Riesling from 1964. Savoury aromas and flavours of beeswax, marzipan, hay, toast and mushroom dominated, but there was still sufficient lime peel, dried apple and marmalade for balance and whilst it was fully developed, it certainly wasn’t tired or past its best.

Wines produced in cool climates can have very high levels of acidity, and this contributes to reasons why Champagne and English Sparkling Wines can age positively.

• Sweetness

A high level of sugar will also be of benefit to a wine intended for ageing. Sauternes, Tokaji and Auslese Riesling are wines that have high levels of sugar. In a similar way to acidity, the sweetness acts as a preservative, slowing the oxidation and enabling more reactions and therefore the development of more positive flavour changes. The wine will feel drier as it ages. The sweetness doesn’t actually change but as the savoury flavours develop they distract the taster from noticing the wine’s sweetness. Bitterness levels will increase, which balances the sweetness and the wine will appear drier as it ages.

Predicting how long to keep a bottle of wine …

Mostly, trust your wine merchant. Wines sold in supermarkets are intended to be drunk either immediately or within 6 months of purchase. You can assume they will have been aged to an appropriate level by the winemaker before they are put on the shelves.

Price is a rough guide. Wines with the required high levels of concentration, acidity and sweetness can be linked to price, with the potential for positive ageing increasing as wine costs. Consider ageing a £10-15 wine for 3-5 years, a £15-25 wine for 5-10 years, and a £25 plus wine for ten years or more.

If you buy from a specialist such as The Wine Society or your local independent merchant, ask them for their advice. They’ll have already tasted the wine and made an assessment for you as to when it should be drunk.

Taste more! As you become more experienced at assessing a wine and assessing it rigorously and tasting youthful, developing and fully developed wines, you’ll better understand the qualities a wine needs to age positively, be able to assess a wine’s potential for ageing and be able to predict the changes that might occur.

The WSET Level 3 Systematic Approach to Tasting has been developed to help tasters, professional and enthusiast, to better understand the criteria used to assess and evaluate the development and potential for ageing of a wine.