Lesson 6 - Refrigeration Theory and Cycle

Refrigeration is defined as the process of removing heat from an enclosed space, or from a substance, for the purpose of lowering the temperature. It utilises many of the same principles discussed in the unit on Heat Transfer. Refrigeration is needed all over the world to inhibit the spoilage of perishable foods, and it is also used in many places throughout a brewery.

Refrigeration is expensive, and is often one of the largest single uses of electricity within a brewing and packaging facility.

In a brewery, refrigeration is needed in many areas. For example, it is essential for the storage of raw materials like yeast, and to cool wort or beer in fermenters and maturation tanks.

In early times before refrigeration technology was developed, many forms of natural cooling were used to keep things cool. Ancient civilisations used ice and snow, transported from the mountains. Older breweries, such as the original MillerCoors brewery in Milwaukee, Wisconsin, used underground caves for cold storage – which you can still walk through today!

Thankfully, artificial cooling using mechanical refrigeration has been developed to better manage cooling operations. Mechanical refrigeration is used via compression chillers and specific fluids called refrigerants, to keep things cool around the brewery.

It might be helpful now to point out the difference between cooling and attemperation. Cooling is the act of lowering the temperature of a desired space or fluid. Attemperation is the regulation of a space or fluid to a constant temperature. As an example, after boiling, wort is cooled to the target start of fermentation temperature. Throughout fermentation, the wort/beer is attemperated to the desired fermentation temperature. The rest of this lesson will describe the refrigeration process used to achieve both cooling and attemperation.