What Really Happens as Wine Ages?

By Andrew Donaldson
What Really Happens as Wine Ages?

Like a great old vintage, we thought this article from Anne Krebihl MW was too good not to share.  Read below some straightforward insights into the ageing of fine wine.

Most wines sold in the world today are made for immediate consumption without the need for cellaring (our Pinot Noir Blanc for example). Some wine lovers, however, prefer to "lay wine down," or store bottles for a few years in order to enjoy them when the flavours have evolved.

So what happens as wine ages, and how do its flavours change? Which wines should be aged? And, most importantly, why do we age wines at all? Here’s what you need to know.

What happens to wine’s flavour as it ages?
When wines are young, we taste their primary flavours, like grassiness in Sauvignon Blanc, plum in Merlot, apricot in Viognier or citrus in Riesling. We may also notice some secondary notes associated with winemaking techniques, like the vanilla flavour of oak or buttery nuances from malolactic fermentation.

When wines age, we start speaking about tertiary notes, or flavours that come from development. This could mean young, bold notions of fresh fruit that become gradually more subdued and reminiscent of dried fruit. Other flavours, previously hidden by bold primary notes, come to the fore, like honey, herbal notes, hay, mushroom, stone and earth.

What causes these changes? Nothing in wine is ever static. Acids and alcohols react to form new compounds. Other compounds can dissolve, only to combine again in another fashion. These processes happen constantly and at different rates. Every time you open a bottle, you catch the wine at another stage in its development, with new and different nuances. While the proportion of alcohol, acids and sugars stay the same, the flavors continue to change.

How texture develops in wine
Texturally, the wines also change. Dry, aged white wines can become almost viscous and oily, while reds tend to feel smoother. This is due to phenolic compounds like tannins falling out as sediment over time.

In a young wine, these compounds repel each other, staying small enough to remain suspended in the wine. As the wine ages, they lose their charge and start to combine, forming chains and becoming larger and heavier. This reduces the surface area of the tannins, causing them to taste smoother, rounder and gentler.

Once these combined compounds become too large, they fall out of suspension as sediment. Some red wines throw heavy sediment, others almost none.

How wine colour changes with age
One of the most visible processes in an evolving wine is slow oxidation. Colour is the most obvious indicator of this.

As white wines age, they often evolve from pale lemon or golden to amber and even brown. Vivid salmon-hued rosés can take on onion skin tones as they age. As reds develop, oxidation often moves them from the purple end of the spectrum toward tawny or brown hues.

While young reds can be opaque when held against a white background, mature reds often show a lighter colour around the edges. This is known as "rim."

The rate of oxidation depends on the amount of air left in the neck of the bottle after it was sealed, and how permeable the closure is. Traditionally, natural cork has allowed minimal oxygen exchange, which is why most wines deemed age-worthy are still bottled under cork. However, since cork is a natural product, there is no such thing as uniformity. This can cause considerable bottle variation in the same case of wine.

Which wines can age?
It’s often assumed that only the finest, most expensive wines can age, but any well-made wine stands a good chance of developing.

Entry-level wines from good wineries can easily age from three to five years unless they’re made for primary, aromatic appeal like an easy Moscato. Wines that have real concentration of flavour, with a good balance of alcohol, acidity and texture, should age well.

But some wines are made specifically for extended ageing, like very extracted reds with bold tannins that need some time to mellow. These comprise many of the fine wines of classic European and New World regions..

White wines that can especially benefit from ageing include Riesling, Sémillon, Chenin Blanc, Furmint, white Bordeaux-style blends, white oak-aged Rioja, oak-aged Sauvignon Blanc and good Chardonnay. Some Albariño, Garganega and other lesser known regional grapes can also age well.