Wine is a living product, extremely sensitive to environmental conditions. A variation of just a few degrees at the wrong moment can alter fermentation, accelerate ageing or ruin months of work.
That is why temperature control in a winery is not an add-on: it is one of the most important technical decisions that directly affects the quality of the final product.
Temperature during fermentation
Alcoholic fermentation is an exothermic reaction. The tanks generate heat which, if left uncontrolled, can raise the temperature to levels that kill yeast or produce off-flavours.
For white and rose wines, fermentation is controlled between 14 C and 18 C, which preserves the fruity aromas and freshness. For reds, the typical range is 24 C to 28 C, since greater extraction of colour and tannins is desired.
Maintaining these temperatures requires refrigeration systems capable of absorbing the heat generated by fermentation continuously and steadily. Abrupt fluctuations are just as damaging as extreme temperatures.
Ageing and maturation
In the barrel room, thermal stability is paramount. The ideal temperatures for barrel ageing range between 12 C and 16 C, with a relative humidity of 70% to 80%.
Excessively high temperatures accelerate the wine’s evolution in an uncontrolled manner, while temperatures that are too low slow down the processes of micro-oxygenation and maturation. In either case, the result moves away from the profile the winemaker is seeking.
Humidity is also critical: if it is too low, evaporation through the barrel (known as the “angel’s share”) increases and volume is lost. If it is too high, it encourages mould growth.
Storage and conservation
Once bottled, wine remains sensitive to temperature. Storage cellars and bottle racks should be maintained between 10 C and 14 C to ensure slow, controlled evolution.
Sudden temperature changes are especially harmful at this stage, as they can cause expansion of the liquid that compromises the cork seal and facilitates oxidation.
HVAC systems for wineries
The thermal requirements of a winery are very specific and cannot be met with conventional HVAC equipment. The most common systems include:
- Water chillers: these generate chilled water that circulates through the jackets of fermentation tanks and through the coils of room air handling units. They are the heart of a winery’s refrigeration system.
- Glycol-water circuits: in applications where temperatures below 0 C are needed (such as tartaric stabilisation), a water-glycol mixture is used that allows operation without risk of freezing in the circuit.
- Low-temperature (LT) equipment: required for processes such as cold stabilisation, where the wine is brought to temperatures of -4 C to -6 C for several days to precipitate tartrate crystals before bottling.
- Room air handling units: units that simultaneously control temperature and humidity in barrel rooms and storage areas.
The importance of bespoke design
Every winery has unique conditions: geographical location, orientation, production capacity, types of wine and the stages of the process that take place on-site. An effective HVAC system must be designed specifically for each case.
Over-sizing is just as problematic as under-sizing. An excessively large unit starts and stops constantly, generating temperature fluctuations. An undersized one cannot maintain the required conditions during peak demand, such as during the harvest.
Climate control that respects the wine
At Acoval we have extensive experience in the design and installation of climate control systems for wineries in the Valencian Community and other wine-producing regions. We work with chillers, glycol circuits, low-temperature equipment and room air handling units, adapting each installation to the specific needs of the winery.
If you are planning a new winery or need to upgrade your temperature control system, we can help you find the technical solution that your wine demands.
