Vacuum Coolers for Cooling Vegetables
Vacuum Coolers essentially create a vacuum in a sealed chamber with the produce, usually leafy vegetables such as lettuce, where a great deal of the surface area of the tissues are exposed to the vacuum.
As the pressure falls, water in the tissues literally begin to boil and turn to vapor. This energy is known as the Heat of Vaporization. The change of state must pull heat from somewhere, so it pulls it from the plant tissue – rapidly, depending on the vapor-pressure.
This is fine for rapid cooling, but it also is stressful to the plant tissues and excess water can be driven off by the process – resulting in a loss of sellable weight.
Vacuum Coolers are structured for the forces from the vacuum pump removing air from the chamber.