As we all know, beer fermentation needs to be carried out at a relatively low temperature, so the temperature of the fermentation tank must be controlled within a certain range. Fermenting in an unconditioned space can cause temperatures to drop so low during the winter months that the fermentation process can stall or slow down significantly. On the other hand, allowing temperatures to rise during the warmer summer months can also slow down fermentation and result in off-flavors. This temperature issue means that spirits produced in winter may have a completely different flavor compared to those produced in summer. Therefore, the obvious solution to maintaining consistent flavor profiles throughout the year is to keep the fermentation temperatures as stable as possible.
So how do we keep the fermenter temperature stable? Using a Cooling Jacket on a Fermenter
The fermentation cooling jacket is an additional layer that wraps around the main vessel. Essentially, it acts like another tank that surrounds the internal wall of the fermentation vessel. There are inlet ports and outlet ports that allow a cooling medium to circulate through the jacket. Typically, controlling the flow rate of the cooling medium helps regulate the fermentation temperature. The jacket functions as a heat exchanger, transferring heat between two fluids – the cooling medium and the fermenting beer or wine.
Could we use a large immersion coil to circulate the cooling medium? Yes, but the downside would be that we might need to increase the flow rates of the cooling medium or lower its temperature to achieve the same efficiency as the much larger surface area provided by the cooling jacket. Additionally, cleaning the cooling coil could add unnecessary labor hours for cleaning and sanitizing the fermentation tank. As mentioned in previous blog posts, labor hours will almost always cost more than the specific equipment designed to reduce those labor hours, over the course of one, two, or three years. Having the right equipment for the job makes the workplace safer, more productive, and ultimately reduces the operating costs of your distillery.
Some fermenters are designed for solid grain fermentation, while others have the more traditional conical shape often seen in breweries. In both designs, having a cooling jacket helps ensure that fermentation completes successfully, minimizes off-flavors caused by stressed yeast, and reduces the labor hours needed to clean and sanitize the vessel.