They say that moving house is among the most stressful experiences of adult life – something that, after a supposedly idyllic move out of London and into the country last summer, I can certainly vouch for. I didn’t make things easy for myself, however. With more space at my disposal, I had giddily decided to consolidate my sprawling wine collection, bringing it in from various merchants and an entirely unsuitable London flat into our new rural retreat. With no cellar on the property, I decided to go the whole hog and have purpose-built storage constructed.
So far, so good. Until – and I’m rather ashamed to admit this – I came to consider the spirits. Those who know me will know that spirits, notably whisky, are by no means an afterthought in my collection – indeed, I have more than a few bottles, including some older, rarer whiskies. But when considering storage, it was wine that had preoccupied my thoughts. Why? And should I simply store my prized Scotch in the same place as the classed-growth Bordeaux?
We all know that wine needs certain conditions to age to best effect, especially if it is being stored for a long time. What is less well known and understood is how best to treat bottles of spirits. Unlike wine, spirits don’t evolve in the bottle, and most people probably feel they’re sufficiently durable to be just left alone in a kitchen cupboard. But do they benefit from certain specific storage conditions? The short answer is yes. But like everything about wine and spirits, there’s more to it than that, and understanding the whys and wherefores helps us find the best solution.
Do you need to worry about the bottle’s seal?
It’s true that spirits don’t evolve once bottled, but certain factors need to be constant to ensure this. Primarily, the closure needs to be sound. During the 19th century, cork was the only option – if spirits were bottled at all. (Most merchants would purchase a barrel, and customers would bring their own containers to fill.) From the early 20th century, spring caps were used on many bottles, especially whisky. These caps were pretty reliable and created a good closure. Then came screwcaps, which also tend to have a good seal. But more recently, the cork seal has made a comeback. There is a certain romanticism surrounding the opening of a bottle that has a cork seal, and in the age of premium spirits, cork is almost always used. With wine, cork imparts a benefit when storing bottles over a long period of time, because the wine breathes through the cork and ages accordingly. With spirits, however, the cask is for maturation and the bottle is for preservation, and a cork closure can create problems if the bottle is stored badly.
Spirits that have great age and are cork-sealed are likely to lose liquid through evaporation. It’s easy enough to replace the cork, in the same way that many high-end wines will have the cork replaced over time. But for a belt-and-braces approach, an extra seal should be added – even rudimentary applications such as clingfilm or electrical tape – to ensure that the seal is sound.
As far as the actual storage goes, a cork can be corroded by spirits, especially those of high alcohol levels, so it is strongly recommended to store the bottle standing up – the opposite of wine. Standing up, however, the cork may dry out over time, so the humidity of the storage area needs to be considered: too dry, and the cork crumbles; too damp, and the cork becomes mouldy and loses its integrity.
What humidity and temperature levels are best?
Like wine, spirits (especially barrel-aged spirits) benefit from being kept out of sunlight and are best kept in cool conditions to help prevent evaporation. Like wine, spirits can be stored in quite a range of humidity – around 50–80% relative humidity – and as long as that humidity is constant, the corks shouldn’t expand and contract, and the seal should last. However, the closer to 80% you get, the more likely corks – and labels – will be affected. I would suggest trying to find a happy medium for both wine and spirits to be stored in the same place, with a relative humidity of around 60–70%.
Air conditioning needs to be considered carefully. Choose a unit that won’t struggle to keep the area cool, therefore making it easier to be constant, which will also be more energy efficient. Humidity presents a different kind of challenge – as I discovered. By chilling the area, the air can hold less water vapour than when warm, and the relative humidity can rise easily, getting over 80%, so a dehumidifier should be used. The dehumidifier needs to turn on automatically when a certain percentage of humidity is reached and off again when that humidity has reduced.
For spirits, the cool temperature that wine is stored in (10–16°C) is perfect, and as long as the humidity can be kept at 60–70%, the spirit inside will last a lot longer. This I found was the trickiest – but, to be honest, one of the least important – issues to monitor. I bought a dehumidifier that needs to be emptied every day or two, which means that when I go away for more than a couple of days the humidity rises above optimum levels. Fortunately, our builder had at least thought about damp and lined the floor with a damp-proof course and used thicker than normal insulation, so that the air conditioner doesn’t have to work so hard.
Damp can be an issue, so where the humidity can’t be controlled, take the bottle out of any packaging, to avoid the latter being affected by damp, and wrap the bottle in clingfilm to prevent any damage to the label. Electrical tape on the cork, clingfilm on the labels, and no fancy packaging: it might not make for the most photogenic of storage conditions, but it’s the safest.
How should opened spirits be stored?
One last point: most people assume whisky does not deteriorate once opened and exposed to the elements. This is not the case. Like wine, whisky will oxidise, although it does take a very long time. There are two processes I use to manage this. If it is a rare bottle that I don’t intend to open often, I use a Coravin Pivot, squirt a little gas in the bottle and replace the cork. Once the bottle is down to around a third of its original contents, I decant it into a smaller bottle to reduce the head space and, therefore, the exposure to oxygen.
Of course, ultimately, the easiest way to prevent any such issues is simply to drink it.