Aged wines are a bit of a rarity and usually command a higher price when compared to young drink-now wines… up until optimum drinking, from there they can lose value quite quickly.
Young drink-now wines are typically driven by their fresh primary fruit whereas aged wines tend to be more complex showing flavours that can only be achieved with time. The fragrance of young wine is often referred to as aroma whereas aged wine as bouquet.
Wines that are produced to be consumed young are unlikely to be good candidates for considerable ageing. The best candidates will likely be a bit too sharp in acid or a bit too dry with tannin when young. Ideally there should be some good background fruit as well.
Whilst Riesling, Chardonnay, Semillon and Chenin Blanc can develop very enticing secondary characters, it is usually reds that are thought to be the best candidates for ageing. As wines age monomers polymerise, that is, small molecules grow bigger as they find mates they can join on to. These longer molecules add to the viscosity of the wine and in red wines often become too large to stay in suspension and will ultimately form a crust in the bottle.
The quantity of acid in the wine doesn’t change much with time but the perception of the acid does due to this polymerisation. Acid and tannin protect the wine so wines with levels of acid and tannin that are a bit offensive early on will likely age better than wines that are very easy drinking when young.
Red wine colour is the result of pigmented tannin. These are formed from catechins (colourless tannins) and anthocyanins the colour molecules (“cyan” in the middle gives a clue). Anthocyanins are abundant in nature and are responsible for the red to blue colour of many flowers and leaves. Grapes and very young red wine tend to have a more blue/purple colour from the anthocyanin monomer. In the presence of acid and oxygen during fermentation and maturation the catechins react with the anthocyanins to form pigmented tannins which take on a more red hue and contribute to improved mouthfeel.
Tannins are abundant in both red and white grape varieties, but only red varieties have anthocyanins. If a white wine is macerated in the same manner as a red it will simply be too bitter to drink as it lacks the benefit of the tannin mediating anthocyanin.
Wines that are fermented and/or matured in oak barrels also seem to age better. Whilst I haven’t brushed up on the science behind this, I suspect it is due to the addition of wood tannin and molecular oxygen to the wine that sets it up to go the distance.
I think I have talked enough about tannin, but oxygen is worth exploring a little here. Anthocyanin and catechin form more desirable polymers in the presence of oxygen and the oxygen that migrates from oak staves into the wine is in the desirable molecular form that does not contribute to oxidised characters. Wines that are protected against oxygen during processing are typically more delicate and easily damaged by oxygen later in their evolution than wines that have been exposed to oxygen during processing and maturation.
Some grape varieties age better than others and wines from certain regions age better than others, but I won’t explore this at this time.
The ideal temperature for ageing wine seems to be around 12C to 14C. Wines will age quicker when stored at higher temperatures but some of the more complex flavours are often lost. At 12C to 14C the wines should develop uniformly and show their best… if you are patient.
Wines with natural cork closures are best aged on their side or upside down to keep the cork from drying out and losing its ability to seal the bottle.