From a physical perspective, cooling is a straightforward process. However, in practice, breweries have the option to employ different methods of heat transfer. This can be achieved through the use of either single-stage plate heat exchangers, which rely solely on chilled water, or multiple-stage plate heat exchangers, which use a combination of ambient water and glycol. When the wort enters the heat exchanger, its temperature ranges from 96 to 99°C, and it exits the exchanger cooled to the desired pitching temperature.
To accomplish the cooling process with a single-stage system, breweries utilize a cold-water tank jacketed with glycol to effectively cool the wort.
In a two-stage system, the first stage employs water as the primary coolant to remove the majority of the heat, bringing the incoming wort to a temperature within 3°C of the fermentation temperature. Subsequently, in the second stage, the wort is further cooled to the desired fermentation temperature using a secondary refrigerant, such as glycol or ammonia.