How does a fermenter cooling jacket work?

As we all know, beer fermentation needs to be carried out at a relatively low temperature, which requires the temperature of the fermentation tank to be controlled within a certain range. Fermenting in an unconditioned space can allow temperatures to drop so low during the winter months that the fermentation can stall or severely retard completion. On the other hand, allowing temps to spike during the warmer summer months can retard completion and impart off-flavors. This issue of temperature can mean that spirits produced during the winter months may very well have a completely different profile compared to spirits produced during the summer months. So, the obvious solution to help maintain uniform flavor profiles throughout the year is to keep fermentation temperatures as consistently as stable as possible.

So how do we keep the fermenter temperature stable? A Cooling Jacket on a Fermenter

The fermentation cooling jacket is an additional skin that wraps around the primary vessel. Essentially, a cooling jacket on a fermenter acts like another tank that wraps around what will become the internal wall of the fermentation vessel. There are inlet ports and outlet ports that allow for a cooling medium to be circulated through the jacket. Typically, the flow rate of the cooling medium can be used to control the temperature of the fermentation. The jacket, simply put, is a heat exchanger that transfers heat between two fluids. One fluid being our cooling medium and the other being our fermenting beer or wine.

Could we use a large immersion coil to circulate our cooling medium? Yes, but the downside would be that we could have to increase the flow rates of our cooling medium or reduce the temperature of our cooling medium to be as efficient as the much-larger surface area that the cooling jacket provides. Additionally, cleaning the cooling coil could amount to an unnecessary addition of labor-hours needed to clean and sanitize our fermentation tank. As mentioned in previous blog posts, at the end of the year (or two or three), labor hours will almost without exception cost more than the actual equipment that is specifically designed to reduce the very same labor hours. Getting the right equipment for the job makes the workplace safer, more productive, and ultimately reduces operating costs of your distillery.

Some fermenters are designed for grain in solids fermentation and others are designed in the more traditional conical shape often seen in breweries. In both designs, having the cooling jacket will help to ensure that the fermentation finishes to completion, minimizes off-flavors associated with stressed yeast, and reduces labor hours needed to clean and sanitize the vessel.