Making a Wine Cellar
There are whole books written on the construction of an ideal wine cellar, so it is clearly a process which many people take very seriously. When selecting a location in the home for a wine cellar, which in many cases is above ground and not a true cellar at all, temperature control is the main concern (read more on the importance of temperature in my feature on the ideal wine cellar). Before commencing it is wise to purchase a thermometer which records maximum and minimum temperatures. This is the most essential piece of equipment for any cellar.
Those who have the luxury of several rooms to themselves may wish to devote one entirely to the storage of wine. Turning off the radiator and drawing the curtains are excellent first steps towards achieving a cool, stable temperature. In all locations a container of water will help to maintain a slightly improved level of humidity. For those who demand perfect, long-term storage, a dedicated, insulated, humidity and temperature controlled air-conditioned room is the ideal. This is especially important in warmer climes, where summer temperatures may be baking hot, but in the UK and other temperate regions this is not at all essential.
For most people, however, the search for a location for a wine cellar usually involves otherwise little-used areas and cubby-holes, as well as the attic, sheds and other outbuildings. I strongly advise against the temptation to store wine in the attic. Just a short period of monitoring reveals that attic temperatures fluctuate wildly, reaching sweltering levels at times. Outbuildings, such as sheds, garages and old outside toilets are always tempting locations, but these should be approached with caution. Here the risk is freezing, as temperatures may drop extremely low during the winter months. There are also security issues with storing your wine in what is a traditional target for the burglar or opportunist thief.
The best option for many is the under-stairs cupboard, and in older houses the larder area. For those in flats with no such facility the insulation of a freestanding cupboard or wardrobe may be the best option, but in these conditions wine should be kept for only mid-term storage, perhaps five years or so. For bottles demanding more age than this other solutions should perhaps be sought.
Other such solutions include a temperature-controlled wine cabinet, a piece of kit rather like a refrigerator, but operating at a temperature suitable for the storage of wine. Such units offer an excellent solution and guarantee piece of mind where wine storage is concerned, although you must always be sure to purchase one with a sufficient capacity for your needs; otherwise after a few years your next concern may be where to locate your second such cabinet. A similar option is to pay for professional storage of the wine. Many merchants will offer this service, although it is important to ensure that your wine is clearly labelled and kept separate from the merchants stock, in order to ensure it isn’t sold, and that it can be rescued in the event of the merchant's business folding. There are other businesses offering specialist facilities for wine storage, although these tend to be aimed at the wine trade itself and are consequently unfavourably priced for the wine drinker wishing to store just a few cases.
These common-sense measures are the first and most significant steps to constructing a suitable area for wine storage, but are there any other methods we can use to encourage temperature stability? When considering methods of influencing the temperature within an above-ground wine cellar, it is worth considering the physics of how heat is transferred. These are as follows; conduction (transfer of heat through materials in contact), convection (transfer of heat by movement of molecules), radiation (transfer of heat by electromagnetic radiation) and evaporation (which consumes latent heat, and is not of great concern when discussing wine cellars). Taking conduction first, this is transfer of heat from materials in contact with one another. Hence warmth from the air outside the cellar is transmitted to the wall, which warms up, and consequently the air within the cellar warms up also. 'Heat differential' has a significant effect on heat transfer into the cellar, i.e. the warmer it is outside the cellar the quicker it will warm up inside. When choosing a location for an above-ground ‘cellar’, the heat differential can be reduced by locating the cellar somewhere that has an outside wall, where it will usually be cooler, especially if it is north facing. Insulating the walls and doors with materials, such as polystyrene, foam or pillows of loft insulation, will slow the transmission of heat into the cellar. Moving on, convection is the transfer of heat by mass movement of substances - in our case the movement of air through a draughty cellar. Blocking off gaps around the door will thus reduce heat transfer into the cellar.
Suitable insulation and draught-proofing reduces heat loss by conduction and convection, but what role do the other methods of heat transfer have to play? In the case of evaporation, very little, but manipulation of heat loss by preventing radiation can have a significant effect. The internal temperature of a room or building can be markedly influenced by changing the colour of the inside and outside surfaces. Black or dark surfaces absorb heat, whereas white or light-coloured surfaces reflect heat. Painting the outside surface of a cellar white will reduce heat absorbed from the outside, whereas painting the inside black will reduce the emission of heat into the room. I know from personal experience that whitewashing the roof of my first ever ‘cellar’, which was an outbuilding constructed of stone covered in a bitumen roof, resulted in a reduction of the average internal temperature by 2ºC. That’s a big difference.
Other than temperature, the only characteristic of a cellar that is of great concern is humidity. As mentioned above, low humidity is not a problem, as it is easily corrected by placing a container of water in the room, the aim being not to make the room damp, but rather to improve on the very dry air that occupies many centrally heated homes. Very high levels of humidity, however, can be a problem. In a very damp cellar, paper, cardboard and similar materials quickly moulder and rot away to nothing. If the wine is stored in cardboard boxes, which isn’t ideal, care should be taken when moving them. It’s very likely that the box will fall apart when moved, with the risk of subsequent breakage of the precious bottles within. This can be easily avoided, however, by storing the wine in wooden packing cases (which will still rot, but over a much longer time period) or preferably a wine rack constructed of some resistant material, such as pressure treated timber or galvanised steel.
A much more serious consequence of humidity, however, is its effect on wine labels. As most of these are made of paper (some nowadays are plastic or plastic-coated, and are thus resistant to rot), they quickly moulder away, as with the bottle shown here on the left. Once a label is damaged in this way, there are two problems. First, and most importantly, the identity of the wine is lost. This makes opening it something of a lottery. Secondly, for those who have suitable bottles, the resale value is lost. The wine aftermarket greatly prefers bottles with pristine labels, and will pay a premium for such wine. Many wine writers recommend spraying the labels with hairspray, which supposedly forms a lacquer-like coating over the paper label, thus protecting it. In the past when I had a very humid cellar I never found this technique to be of any great success. It also introduces unwanted odours into the cellar. A quick wrap of Clingfilm around the label, however, has in my experience always been effective, and is also odour-free.
Light & Vibration
The internal light is easily moderated. External windows, if any, should be covered to exclude light. Vibration is not a great concern. (Updated 26/11/11)