What temperature and humidity does wine need?
For storage, around 10–15 °C and humidity between 55 and 65 per cent suit it. Those figures come from the wine-storage system maker Wine Guardian. Stability matters even more: abrupt temperature swings make wine contract and expand, the cork shifts and air gets in.
Heat, light and vibration harm wine more than a degree of inaccuracy. So in a cellar project the main thing is not the number on the thermometer but that the temperature stays even through the year and the room is dark and quiet.
Can I build a wine cellar in a flat without a basement?
You can, even in central Barcelona. Three options work: an insulated room with its own climate, a glazed volume in the living or dining room, or a climate cabinet. The choice depends on the number of bottles and whether the flat has a windowless room.
The best spots in a flat: a windowless interior room, a large store cupboard, the space under the stairs in a duplex, part of a corridor closed off with a wall. Stay away from heat sources: the kitchen, boiler, washing machine, a south-facing outer wall. A room on the north side of the building is colder and the climate unit works less hard.
For a small collection a row of wine cabinets solves it without building work. A room pays off when the collection exceeds a few hundred bottles or you want to see the wine as part of the interior. For a capacity estimate, by eye about 80–100 bottles per linear metre of two-metre-high shelving in a single row.
How does a climate room differ from a cabinet?
A cabinet holds a limited number of bottles with built-in cooling, whereas a room needs insulation, a vapour barrier, its own cooling system and an airtight door. A room gives more space and the feel of a collection, but costs more and is more complex to design.
Cabinet: a finished product, plugs in, holds from a few dozen to a couple of hundred bottles. No building work but a recess for built-in installation and ventilation to remove heat. Room: a fully designed space whose walls, floor, ceiling and door are insulated, with cooling sized for the volume.
The line depends on the aim. If there are few bottles and you drink them within a few years, a cabinet is enough. If you are building a collection for many years, you need a room with a stable climate. For a showcase in the living room there is a third way: a glazed volume with its own cooling, which is also part of the interior.
How do I insulate a cellar and avoid condensation?
Insulate every enclosing surface and put a vapour barrier on the warm side. Condensation appears where warm, humid air meets a cold surface. The issue is not that there is cold, but where and how it touches the warm side.
In practice: walls, ceiling and floor with rigid insulation of the required thickness, a continuous vapour barrier towards the living rooms, and joints and service penetrations sealed. The door airtight with a perimeter seal, ideally a purpose-made cellar door or a glass one with double or triple glazing. The glass must be multi-chamber; otherwise it condenses on the cold side and mists on the warm.
Do not run underfloor heating from an adjoining room beneath the cellar. More on insulation principles in the article on thermal insulation. In an Eixample flat with high ceilings, the space for insulation is taken from the ceiling and walls, not from the clear height.
Do I need a separate cooling system?
Yes. An ordinary air conditioner does not suit: it dehumidifies, cycles and causes temperature swings. You need a system made for wine rooms or a climate unit with precise temperature and humidity control.
The system is sized to the volume, heat gains and amount of glass. Its compressor and condenser reject heat: usually outside, through ducts or on the facade. An outdoor unit in Barcelona may need a facade installation permit, as in the article on air conditioning on the facade. So the machine's location is planned in the design, not after the walls are built.
Allow for noise and vibration. The compressor goes on anti-vibration mounts, away from bedrooms and the neighbour's wall. The condensate drain needs an outlet. If humidity falls too low a humidifier is needed; in the damp coastal climate, by contrast, dehumidifying is the more common task.
What lighting does not harm wine?
Direct sunlight, ultraviolet and the heat of lamps harm wine. LED lighting in a warm tone, around 2700 kelvin and without ultraviolet, switched on only while visiting, is suitable. Sources must not warm the bottles.
Ultraviolet triggers chemical reactions that quickly change the taste and aroma of wine, as Wine Guardian warns. So the cellar window is closed, and glass doors use laminated glass with a UV filter. LED strips in niches and shelf lighting neither heat nor emit ultraviolet, but are best on a motion sensor or switch so they are not on all day.
On lighting scenes, more in the article on interior lighting. For a cellar two are enough: a working one for choosing a bottle and a soft one for display. Incandescent and halogen lamps are not used, because of the heat.
Which racking should I choose and what should the design consider?
Choose timber or metal racking with bottles lying horizontally, with spare height and depth, mounted apart from vibrating surfaces. Plan with room to spare: the collection almost always grows.
Check in order: the load capacity of the slab (bottles weigh more than they seem), access to service the cooling equipment, drainage and a dedicated electrical circuit with its own breaker. The racking timber is chosen with humidity in mind: untreated solid wood absorbs it, lacquer holds it back. With the neck tilted down the cork stays moist, so horizontal storage is a must. For display shelves, think about lighting and mirrors that visually enlarge the volume.
We run renovation and interior design. One person responsible for the site stays in touch in Spanish and Russian, payments follow stages under the contract and we give the exact price after the visit and measurements. If you want a cellar, we will tell you where it fits in your flat and agree the location of the equipment before work begins.
Frequently asked questions
What temperature and humidity does wine need?
For storage about 10–15 °C and 55–65 per cent humidity, according to the wine-storage maker Wine Guardian. Stability matters more: swings harm the cork. The room should be dark and free of vibration. Light and vibration matter too: the room should be dark and calm.
Can I have a wine cellar in a flat without a basement?
Yes. Options: an insulated room with its own climate, a glazed volume in the living room or a climate cabinet. Best spots: a windowless interior room, a large store cupboard, the space under the stairs. Keep away from the kitchen, boiler and south wall.
What lighting does not harm wine?
LED at about 2700 kelvin, without ultraviolet, on only while visiting, ideally on a motion sensor. Windows are closed and glass doors have a UV filter. Incandescent and halogen lamps do not suit because of the heat. Light it only while visiting.
Do I need a separate cooling system?
Yes. An ordinary air conditioner dehumidifies and lets temperature swing. You need a wine-room system or a climate unit with precise control. An outdoor unit may need a facade permit, and the compressor goes on anti-vibration mounts. That keeps temperature and humidity steady all year.