A good cellar
What criteria does a cellar need to be considered suitable for keeping wines?
Fundamental conditions are:
- Little or no light
- No vibration
- Regulated hygrometry
- Moderate, stable temperature
- Absence of parasitic adours (fuel, fruit, rotten wood)
- The cellar should be cleared of anything not related to wine, including crates and boxes, apples or other substances that could cause odours or encourage mould or insects.
Passages of light should be blocked so that only low or indirect lighting is used. Wine can actually lose its colour. Avoid neon or white lights at all cost..
Some cellars are subjected to vibrations caused by a nearby subway or roadway. Wines do not like vibrations. In a traditional underground cellar, vibrations are transmitted through the walls. Because of this, in certain cases racks are fixed to the ground, not to the walls. If there is a real problem of this sort, the racks can be set on rubber silentblocks that absorb the vibrations.
A cellar needs a certain amount of humidity, somewhere in the vicinity of 60 – 90%, ideally between 70 – 80%. Below 60% puts the corks at risk, as they will tend to shrink and become porous. This may result in an all-too-easy air passage for the bottles. Above 85-90% may cause the wine labels, thankfully not the wine, to decay or come unglued. The constant presence of a hygrometer is the most efficient way to evaluate the humidity and to keep abreast of eventual fluctuations.
Although the ideal temperature for storing wines is 12°, few cellars maintain a consistent temperature. Naturally wines can tolerate a few degrees of variation over and above this ideal point as long as those variations occur progressively.
What wine does not tolerate however are abrupt changes in temperature, in other words temperature shocks. Slow changes of 8°C over a year are far more preferable than 4°C changes between night and day.
The warmer the cellar the quicker the wines will age.
Poor hygrometry & temperature: what to do?
Before anything else, install a hygrometer and a thermometer in your cellar (preferably electronic which is more reliable) in order to measure the variations it withstands over the longest possible period. Be aware of confusing sensations: when you enter a cellar whose temperature is 20°C while outdoors it is 30°C, you will naturally have the sensation of a being in a very cool place..
Cellar too humid:
Verify the air vents of the cellar. It is possible to privilege good ventilation on one side and low ventilation on another. Airing should be light in order to cause as little variation in temperature as possible indoors. A ground covering of sand or gravel will help regulate the hygrometry of the cellar.
Cellar too dry:
Same advice as the above paragraph (sand or gravel) except that it should be watered periodically.
Cellar too warm or too cold:
The causes and solutions are the same. The room is too sensitive to the outdoor or indoor environment of the house. However insulation is necessary. Begin by correctly insulating the openings (doors and windows) as well as any source of heating (hot water pipes, heater).
If this is not sufficient, the walls and ceiling (unless the cellar is vaulted) must be insulated. Be sure to use appropriate insulating materials such as polystyrene extruder.
At each stage, observe the changes.
Furthermore, to stabilize the temperature and humidity of your cellar, it is preferable to use elements (compartments, wall decorations, ground cover) in natural or reconstituted stone, or in concrete. These materials will absorb and smooth over the changes. The more mass in your cellar, the better. In fact, it is better to arrange your bottles grouped together rather than individually in separate rack holders.
At this stage, if the conditions of your cellar are still not satisfactory, or if you are aiming for perfection, then the only solution left is to install air conditioning.
Several manufacturers of ready-for-use cellar conditioners exist.
These conditioners are quite simple to mount and do not require complicated service lines.
They will permanently maintain a room of 10³ to 100 m³ at ideal room temperature (ex: 12°) and insure good hygrometry. Whatever the case, this equipment does not allow you to dispense with cellar insulation. Quite the contrary! Before starting up the air conditioning, the cellar, openings, walls, ceiling, and occasionally floor, should be well insulated according to norms prescribed by the manufacturer.
No air intake is required because the air conditioner continuously controls and renews the ambient air.
The room must be impermeable. A quality conditioner adapted to a well-insulated room will consume about as much electricity as a freezer. Do not try to adapt a classic air conditioner that cannot go lower than 16-18° because it could cause your cellar to dry out.