Provided wines are given the right storage conditions as they age, a number of positive things can happen. The flavours develop and mature, the tannins soften and the colour changes. Yet some wines actually deteriorate, losing the charm and fruit flavours they had when young.
A revolution started by Napoleon
Louis Pasteur was the first scientist to study what happens as wines age. At the time, Napoleon wanted to know why wines were deteriorating on their way to market, so he asked Louis Pasteur for some answers. Pasteur investigated the effects of air contact as wines age; too much oxygen exposure oxidised the wine leading to the growth of vinegar bacteria. However, a little air contact actually improved the wine. He then discovered that by sealing the bottle more effectively, wines last longer.
Showing their age
Higher quality wines age better than inferior ones because they have more acids, sugars, tannins, minerals, pigments, esters and aldehydes. As wines age, tannin levels diminish and acid levels reduce.
In terms of flavour, different wines age in different ways. For instance, with a Cabernet Sauvignon, the ‘grippy’ effect of the tannin diminishes, the fruit flavours increase while the oak integrates with the wine and balances with the fruit flavours.
As wines age, ‘secondary’ flavours emerge like toast, toffee, cashew and bacon, in addition to a maturing of the rich berry flavours. Chardonnays tend to develop flavours like caramel, butterscotch vanilla and cashews, while the acids diminish and oak flavours become less dominent.
Not all wines age and improve. Many wines today, even some reds, are made for immediate drinking. Wines like Sauvignon Blancs and Rosés are best enjoyed in their youth when their zesty fruit flavours are at their peak. Yet most other wines age and improve, even for just a few months after purchase. Truly great wines age and continue to improve over many years, some for many decades.
As wines age, the colour changes. Reds change from a vibrant deep burgundy or crimson colour to a lighter brick red. Whites darken moving from pale yellow and green hues to deeper golden tones, while Chardonnays and botrytis-affected Semillons move towards dark honey and toffee colours.
The closure affects the way wines age. Corks allow more air to enter the bottle than screwcaps. In additions, storage conditions affect the rate at which wines age as will the cellaring temperature and atmospheric conditions.