WINETECH Technical Yearbook 2020

the wine, is also an alternative for cold stabilisation. If the mentioned alternatives are not necessarily applied, an innovative approach should be followed to apply cooling as effectively as possible: ● Compressors can for instance be upgraded with variable speed and the manner in which they are utilised, can entail a significant saving in electricity. ● The temperature of the refrigerant is also an aspect that influences the efficiency of cooling. It may for example be unnecessary to operate cooling for the entire year at -8°C. ● If only one container must be cooled, a heat exchanger can be used, instead of

Underground building costs are however high and it is difficult to adjust to existing structures. It is easier to replace the cold stabilisation for tartrate stabilisation by using additives like carboxymethylcellulose (CMC) or potassium polyaspartate (KPA). In the case of young red wines these additives will not stabilise their colour like cold stabilisation. The additives also do not remove the excess tartrates, but prevent their crystallisation. From a financial point of view, CMC (AUS$10/1 000 L) is much cheaper than cold stabilisation (AUS$45/1 000 L) or cold stabilisation with cream of tartar seeding (AUS$80/1 000 L). The mechanical process of electrodialysis, which removes potassium ions from

the use of the complete cooling system. In the same way the cooling system does not need to run continuously if it is not required in the entire cellar. ● If differential electricity tariffs exist at different stages, the brine solution can be over cooled during the lower tariff stages. ● The temperature increase of properly isolated double-jacket tanks is slow and can be seen as a cooling battery. ● Cool ing systems funct ion more effectively in terms of electricity usage per cooling output during the night, when the exterior temperature is lower. ● The ultimate temperature of the brine solution must be adjusted according

to the cooling requirements. The temperature control of fermenting grape juice requires for example a higher brine solution temperature than the brine solution required for cold stabilisation at -4°C. It must always be attempted to use the brine solution at the highest possible temperature, without forfeiting the cooling aims. REFERENCES Mick, H., 2019. Turning down the heat on refrigeration costs. Australian and New Zealand Grapegrower and Winemaker , June 2019: 76-79. Seabrook, A. , 2019. Alternatives to refrigeration. Australian and New Zealand Grapegrower and Winemaker , June 2019: 80-85.

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