What happens as wine ages?

Everyone knows wine undergoes complex changes with age - aromas, flavours and colours can transform to reveal a completely new character. Anne Krebiehl MW walks us through the process....

What happens as wine ages?

As an aqueous solution of alcohol, acids, phenolic and flavour compounds, wine is a complex liquid undergoing constant changes. Its different elements constantly react with each other: water, glycosides, phenolics, alcohols and acids connect and disband, break down and hydrolyse, only to reconnect all over again, at varying speeds and in varying combinations.

Read Anne Krebiehl MW’s feature on ageing your wine in the December issue of Decanter, on sale now. Subscribe to Decanter here.

In this respect wine is like a kaleidoscope: the same elements constantly form new and often beguiling images. At no two junctures will a wine be the same.

That certain flavours emerge and develop is nothing short of alchemy and not yet fully understood. Fresh flavours evolve to evoke dried and even candied fruits; while hints of earth and stone, honey and mushroom, petals and herb appear magically.

Anson: How Bordeaux 1982 wines taste today

Credit: Patrick Grabham

Even decay can smell sweet. In red wine, importantly, phenolic compounds de-nature over time causing them to form long chains. This process of polymerisation decreases their reactive surface and makes the wine less astringent: this is why reds become smoother with age.

Ageing gracefully: Laying down Champagne

Credit: Patrick Grabham

Some of these phenolic chains become so large they eventually precipitate as sediment. With time, the vibrant purple and crimson hues of a red wine turn into vermilion and garnet, while the bright straw colour of white wine becomes increasingly golden and eventually amber. The passage of time thus affects the look, smell, taste and texture of wine.