The Role of Glycol in Temperature Control for Craft Beer Production

Glycol is a type of antifreeze liquid that does not become ice when cooled below 0 degrees C. It is added to the chiller system which controls the base temperature of the glycol running throughout the brewery constant without freezing over like water. It is mixed in a certain ratio with water for efficient heat transfer. It is used to regulate the temperature of Fermentation Tanks , Brite Beer Tanks and the Chill Water Tank.

One of the main benefits of glycol is that it helps in maintaining consistent temperature. The reason that we need consistency of temperature is that the wort needs to be kept at a fixed temperature to produce high quality beer. Once fermentation is over, we need to chill the beer to 2 degree C or lower and keep it at that temperature, the glycol helps achieve this as the chiller keeps the glycol cool throughout the process.

Glycol is always mixed with water in a ratio of around 30/70 or 50/50, which varies depending on the specific needs of the brewery, the temperature range being targeted and the density of the glycol itself.

This mixture is circulated through a series of pipes that are connected to the ‘inlet’ and ‘outlet’ of the jackets on the fermentation tanks. The glycol absorbs heat from the fermenting wort, and the warm glycol is then returned to the chiller where it is cooled before being re-circulated back through the fermentation tanks. This process helps to maintain a consistent temperature for the fermentation process, ensuring the yeast has an optimal environmental temperature to produce the desired flavors and aromas in the finished beer.

We generally use propylene glycol which is a colorless, nearly odorless, and tasteless liquid that is widely used in the brewing industry. It has a lower freezing point than water and is often used as a refrigerant in brewery cooling systems. One of the suggestions that worked for me in the breweries in , that we work at is getting coloured glycol. This really helps in differentiating between any leakage of glycol in the lines vs condensation.

Overall glycol used in the chilling system is an essential part of the brewing process, indirectly allowing control over the temperature of fermentation and keeping the beer at lower temperatures for longer periods of time.