Vacuum cooling is mainly used for cooling of bread and bakery products. Sometimes it is used in other industries. As hot products can’t be placed in refrigerated chambers, it must be cooled.
Advantage of this method is quick cooling of bakery products. Fresh bakery products are cooled:
- on shelves at room temperature – 5-6 hours;
- in the chambers with coolers – –1,5-2 hours;
- in vacuum chamber – 10-15 minutes.
Vacuum cooling: operational concept
Operational concept of this method is based on the cold, which is produced during moisture evaporation. When evaporating, great number of heat is removed from the remaining fluid. For example, when water boiling, all excess heat is absorbed by evaporated moisture. Heat is absorbed from bakery products in the same way. The temperature of evaporation at low pressure is much lower than 100°С. So, if the pressure in chamber is reduced up to 12 mBar, the water is boiled at the temperature 10°С.
Advantages of vacuum cooling
- Time of products cooling is reduced;
- Economical operation;
- High efficiency;
- Quality and tastiness of product are preserved as the moisture from bakery products is evaporated. When usual cooling and freezing, the moisture is frozen unequally that negatively effects the tastiness of the product.
- Storage life is significantly increased. Active generation of bacteria and mould occurs in the temperature range from 70°С to 25°С. When using other ways of cooling, the bakery is in this temperature range from 1 to 6 hours, while vacuum cooling requires 10 minutes.