We all know that beer fermentation requires a lower temperature. During the fermentation process, the metabolic activity of yeast increases the temperature in the tank. Therefore, artificial control is needed to maintain a suitable temperature throughout fermentation.
1. Cooling Methods
First, let’s look at the two cooling methods for conical tanks: indirect cooling and direct cooling. In the indirect cooling method, a refrigerant mixture of ethanol or ethylene glycol and water is used. It is cooled in the evaporator box of an ammonia refrigerator, with a temperature generally controlled at around -5°C. The refrigerant flows in from below and flows out from above. On the other hand, in the direct cooling method, liquid ammonia evaporates and absorbs heat directly in the cooling jacket of the conical tank to cool the wine in the fermentation tank. Liquid ammonia enters from above through the distribution pipe and flows downward.
2. Comparison of Two Cooling Methods
Compared with the indirect cooling method using ethanol or ethylene glycol, direct evaporative cooling of liquid ammonia has the following advantages:
(1) It saves energy by approximately 20%. The compressor in direct evaporation only needs to work at around -5°C, whereas in the indirect cooling method, the compressor needs to work at a much lower temperature, resulting in lower cooling capacity of the refrigerator. Additionally, the delivery volume of liquid ammonia as a refrigerant is significantly less in direct cooling.
(2) It requires less equipment. Direct cooling saves the alcohol water or glycol water required for the evaporation of liquid ammonia and also eliminates the need for an evaporator in the cooling process.
(3) It requires less thermal insulation material and has lower installation costs. With reduced liquid ammonia flow, the diameter of the pipes used becomes smaller, and the number of containers is reduced. This reduces the consumption of thermal insulation materials and saves installation costs.
ACE 5BBL Conical Fermentation Tank
3. Precautions for Using Liquid Ammonia
Due to the significant advantages of direct cooling, more and more breweries are adopting the direct evaporative cooling method using liquid ammonia. However, in the craft brewing industry, many breweries still use the indirect cooling method with ethanol or glycol due to the safety concerns associated with liquid ammonia.
Liquid ammonia is a pungent and toxic substance that can be flammable and explosive under certain conditions. Therefore, its safety must be considered in equipment design. Additionally, liquid ammonia has high working pressure and strong permeability, which requires the fermentation tank jacket to have high-quality welding to prevent any leakage. Failure to ensure proper welding can lead to serious quality and safety issues.
If you plan to use direct evaporative cooling with liquid ammonia for your brewery fermentation tanks, make sure to find a reliable manufacturer to purchase high-quality brewery brewing equipment.
The above information covers the temperature control of conical fermentation tanks in craft beer equipment. I welcome everyone to discuss craft beer knowledge with me! If you need beer brewing equipment or are planning to build your own brewery, please contact ACE.