Immersion wort chillers are the simplest form of all wort chillers, but they have a few important factors that need to be considered to assure the quickest, most efficient use of your wort chiller and chilling water source.
The flow rate of your source water is extremely important in deciding which chiller is right for your needs. An immersion chiller’s performance can vary greatly depending on the amount of water it is given. If you are using a kitchen sink or utility room sink, they will typically be about one-third to one-half the flow rate of a garden hose spigot. This will result in longer chill times if the immersion chiller’s volume is not fully utilized. However, if the chiller’s volume is proportionate to the source water flow rate, the chiller can operate at an optimized state, reducing chill time and waste.
Your source water is another key part of the chilling process. As the temperature of the wort gets closer to the temperature of the source water, there is less energy floating around that is capable of being removed per gallon of source water used. Of course, this will increase the chilling time as well as increasing the water usage.
SOURCE WATER TEMPERATURE:
Wort is a better insulator than one might think. The wort closest to the coils can reach your water source temperature very quickly, resulting in very little chilling taking place, especially during the last part of the chilling process. To keep this from happening, you simply need to move the chiller around the brew kettle or stir the wort throughout the chilling process. This reduces the time needed to chill the wort from boiling to yeast pitching temperature greatly, by more than 50%. In our testing we also found that using pump for wort movement was less effective than manual agitation.
For any chiller, it is important to limit the length of the feed hoses. This allows for increased source water and discharge water pressure, resulting in a greater flow rate. It is less important for a lower flow chiller, but will help keep your flow rate as high as possible.