What happens when you age a wine?
Updated: Jun 6
An incredibly complex chemical process, a lot of which is still not understood, where the various components in wine react to produce new compounds, which then again react with each other, producing new compounds again.
Ageing wine is practice that has been around since antiquity, the Romans realising that storing wine in barrels could improve its flavour. Even the Bible gives a nod to the potential quality of aged wine, written in the Gospel of Luke, “No one that has drunk old wine wants new; for he says, ‘The old is nice’”. The idea of wine improving with age is strangely embedded into our culture. If you’ve ever bought a birthday card, you’ve probably seen the cards telling you ‘Wine improves with age, I improve with wine‘ or the alternative, ‘Just like a fine wine, you get better with age’. And then, we assume whatever that means to be true and thought nothing more. But what happens when a wine ages? Does every wine get better with age? If it does, what is improving and if it doesn’t, why not? Is that 20 year old bottle of plonk that you found in your mum’s cellar going to be the best thing you’ve ever tasted? Spoiler alert: probably not. Here, we answer the questions above and break down, what happens when a wine ages.
What is in wine
The scientific understanding of the chemical evolution occurring over time within a bottle of wine is incomplete. The picture has been filled in partially, but plenty of gaps remain over time. But numerous changes occur over time, between many of the different components inside the bottle. Some things however stay the same: the alcohol content will remain unchanged (although its perception might change); the sugar content will stay the same (there shouldn’t be any yeast left to ferment the sugar into alcohol); the acid levels will decrease only slightly (and hopefully integrate better into the wine) and the water content (approx 85% of the bottle) should remain the same. But everything else is fair game.
What happens when wine ages
There are two key things to note. One: oxygen is vital in the interaction of chemical compounds contained within wine. Two: the elements in wine which change over time evolve individually, but are all inter-related. So which elements change over time? Lets start with the most obvious: colour.
All wines with age will tend towards brown. White wines begin life (to generalise) a straw-like yellow. With time and age, the colour will deepen, taking on amber, orange and then a brown colour. Red wines start out ruby red or with a touch of purple. It will gradually transition towards brick red, then tawny and then brown. Reds differ from whites as a result of anthocyanins, which are colour compounds responsible for the colour of red wines. They’re located in the grape skins and vary per grape variety.
Relevant principally for red wines (although the same will happen for orange wines too), tannins are another compound found in the grape skins. They act as a preservative and anti-oxidant and are the main reason red wines can typically live longer than white wines. When drunk young, a wine high in tannins (Cabernet from Bordeaux, Nebbiolo from Piedmont, Malbec from Argentina, Tannat from Madiran) can be a challenging proposition, the extremely high tannin content resulting in an extreme dry mouth and a pretty unpleasant experience. Over time, tannins polymerise (combine) with other tannins, to form larger chains that eventually drop out of the wine. Which is to say, as time progresses, the tannins will feel softer and softer and the wine a smoother drinking experience.
Tannins also affect colour development in red wines. They combine with anthocyanins, thus as tannins drop out of the wine, so does the colour.
Aroma chemistry in wine is a vastly complex field. Aroma chemistry in aged wine is doubly so. Put simply, primary aromas (those associated with a fresh fruit character) fade with time, to be replaced by a more savoury class of aromas known as tertiary aromas. In white wines, notable tertiary aromas include petrol, honey and nuts. In red wines, eucalyptus, black truffle, forest floor and leather are some aromas to evolve during the ageing process.
Does this happen with all wines? No. The vast majority are intended to be drunk over a 3-4 year time frame, before they start to fade. They lack the complexity and concentration of flavours to evolve in an interesting way. When the primary aromas begin to fade, they are not replaced by tertiary aromas. Instead, the structure of the wine (i.e. acidity, tannins, sugar) become more prominent and eventually, the bottle will taste of vinegar and not much else.
Question of taste
So lets say you have an ageworthy bottle at home. Should you definitely age it? It all comes down to personal taste. If you prefer the fresher fruit that young wines offer, drink it young. Big reds might need some time in a decanter, but if that’s the style you love, power to you. If you’re interested by the savoury complexity that an aged wine can offer, keep it for a few years and sample the magic at a later date. There are no guarantees with ageing a wine: it can develop slower or quicker than you expect.
Not many have the luxury of a temperature-humidity controlled cellar to store their wine. So if you do have a few fancy bottles that you want to keep for a few years, consider the following. The best temperature for long-term storage is generally recognised to be around a constant 13°C and large swings in temperature deleterious for the quality of the wine. So keeping bottles in the kitchen or the garage, both susceptible to large temperature changes on a daily or annual schedule, may not the best. Find the coolest, darkest spot in the house away from radiators. Store them on their side so the cork stays moist – if stored vertically, the cork will dry and shrink, causing premature oxidation of the bottle and ruining your precious bottle. If you have a wine-fridge, these will do. A regular fridge will be too cold for any long-term storage, so keep this for chilling the bottles before you drink them.
In summary, ageing wine is a complex and fascinating process that can result in some unique wines. Few other products exist that can connect you in 2023 with a time and place, far across the world. At Bar Aspen, we offer a range of aged wines for you to try, each with its unique character and flavour profile. Explore the world of old wine with us and discover your new favourite vintage.