Have you ever noticed how red wine changes in the glass, often improving over time? It starts to smell better, the tannins soften and the fruit becomes more pronounced. What causes this development is increased contact with oxygen, which helps the wine to ‘open up’.
This is one of the reasons for decanting a wine, which is essentially the process of pouring the contents from one vessel (typically a bottle) into another vessel (often a decanter). In doing so, you are allowing the wine to come into greater contact with oxygen, letting it ‘breathe’ and show its best side.The other main purpose for decanting is to separate the wine from any sediment that has developed in the bottle over time (a common symptom of extended ageing).
Before you decant a wine, there are a few things to consider that will enhance the outcomes, such as its variety, style and age. If possible, decant in front of a light source or against a white backdrop ‒ this will help you identify any sediment and prevent it from being decanted along with the wine.
How long should you decant your wine for? This will depend largely on the age of the wine you wish to decant, and the variety to a certain extent. As a general rule, we suggest the following as a guideline.
Less than 10 years: 1 to 4 hours The younger and more tannic the wine, the longer you will need to decant. Many young wines can be tight or closed on the nose or palate. When the wine is decanted, it takes in oxygen, which helps release the aromas and flavours. Full-bodied, highly tannic varieties, such as cabernet sauvignon, nebbiolo and mourvedre, benefit from longer decanting in particular. By contrast, light and middle-bodied grapes like pinot noir, gamay, sangiovese, cabernet franc and merlot, have naturally lighter tannins and require less time to open. In either case, don’t leave it too long though as over-extended decanting eventually diminishes the aromatic properties of a wine.
10 to 20 years: 30 minutes to 1 hour For wines that have already matured for over a decade, it’s important not to decant too long prior to drinking. In these instances, the unopened wine is effectively dormant due to the limited contact with oxygen, eg., the small amounts a cork transfers. In addition to releasing aromas and flavours compounds, increased contact with oxygen speeds up the rate at which the chemical reactions that cause wine to deteriorate occur. This is often signalled by acetic aromas and the development of sharp, volatile flavours.
20 years and older: open immediately before serving With extended time in bottle, these wines are typically more delicate ‒ both in terms of flavour and structure ‒ and are best opened right before serving; if you decant for too long, the incredible aromas and flavours will disappear.
If your reason for decanting is to remove sediment, the gentlest way to do this is to stand the bottle upright and allow the sediment to fall naturally to the bottom of the bottle. This can take time, so allowing two days before decanting is optimal, however, even thirty minutes helps. After the deposits have settled, decant gently in one steady stream and stop pouring when you see sediment.
What happens if you decant wine for too long? Too much exposure to oxygen can cause an increase in levels of acetic acid (the same acid found in vinegar) and a sharp, volatile smell develops. This is a good indicator that the wine has become oxidised.
Should all wines be decanted? Decanting is not always a necessity; white, rose and sparkling wines rarely require decanting (an exception might be when a wine is suffering from pronounced reduction and gives a rubbery, struck match smell). As for reds, in some cases it’s better to simply let a wine evolve slowly in your glass rather than risking over-exposure to oxygen. If you’re not sure whether to decant or not, it’s best to taste the wine first and determine if it appears closed and there is something to be gained from more contact with air.