Fdit 4 Inch Stainless Steel 1/2in Thermowell Kit Fast Ferment Thermometer Stainless Steel Thermometer Homebrew Fitting Accessories

This is a great thermowell, but installing it in my plastic 5 gallon beer fermentation bucket was a problem until I figured it out. I also saw online installation directions from a thermowell manufacturer, and here it is: The silicone O-ring should go on the inside of the bucket, and the large steel washer should go on the outside of the bucket. The trick to avoid leaks is that the threads must also be wrapped with PTFE plumbers tape (available in the hardware store... very cheap). PTFE tape is sanitary, so it won't adversely effect your brew. I found the silicone O-ring to be a bit too small in outside diameter, so I also bought one silicone garden hose washer to replace the O-ring. Be sure to buy a silicone washer (not a standard hard or soft rubber one), as it is suitable for direct contact with food items.