A Few Notes on Optimizing Wort Chiller Performance
Immersion wort chillers are the simplest form of all wort chillers, and there are a few important factors that need to be considered to assure the quickest, most efficient use of your wort chiller and chilling water source.
SOURCE WATER FLOW RATE:
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, it will typically have about one-half to one-third the flow rate of a garden hose spigot. For example, our triple feed chillers, such as the Hydra, work best at a 6+ gallon per minute flow rate which would be achieved with a garden hose spigot whereas a kitchen faucet typically outputs 2 gallons per minute resulting in much slower chill times. Conversely, our double feed chillers, such as the Mantis, are restricted to a 2 gallon per minute flow rate and are, therefore, uniquely designed to optimize a kitchen faucet’s flow rate.
Side note: higher flow rate is not always better. It’s only better if you have the right chiller. Running more than 2 gallons per minute into a chiller designed to handle only 2 gallons per minute will only achieve the chilling performance of a 2 gallon per minute flow rate.
SOURCE WATER TEMPERATURE:
Your source water is another key part of the chilling process. The colder your source water, the better performance (speed and water usage) you’ll see out of your chiller. This is because the chilling process slows down as the temperature differential decreases between your wort and the chilling source water.
If you’re chilling with warm groundwater, we have some specific tips to help overcome this challenge. Start by adding 12lbs of ice to 5 gallons of tap water and give the water a couple stirs as the ice melts. Run the chiller off of a garden hose spigot fully open to 10F above your tap water temperature (92F in this example). Then switch over to a utility pump submersed in the ice water that you have ready and run the bucket dry. We recommend a utility pump because the pump needs to have enough head pressure to push a large volume of water through the chiller, whereas a pond or aquarium pump typically won’t have enough pressure to push water through when a restriction, such as a wort chiller, is put on the end. Our testing with this setup was able to chill 5 gallons of wort to 70F in 5 minutes using 82F tap water. Also, remember to only pump the ice water through once in order to have the largest temperature differential between your chilling water and the wort.
Wort is a better insulator than one might think. When chilling, the wort closest to the chilling 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. Moving the wort while chilling helps to break up all the hot and cold spots and reduce the time needed to chill the wort from boiling to yeast pitching temperature greatly. In our testing, we found that chilling efficiency is best achieved by continuously stirring the wort, followed by moving the chiller up and down, whirlpooling with a food grade pump and lastly, not agitating the wort at all.
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. We recommend the shortest hoses possible. For example, in our testing, we use six foot hoses for both input and output.