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December 12, 2017
Last updated

How to Insulate a BIAB / Brewing / Boil Kettle

Owner of Clawhammer Supply
how to insulate a brewing kettle

Achieving a vigorous boil with only 1650 watts can be tricky, but with kettle insulation as well as very precise lid placement, it isn't a problem. In this quick tutorial we add add insulation to Clawhammer Supply's 10.5 gallon BIAB Homebrew System.

For the full (and very nerdy) article on boil mechanics, brew chemistry, etc. Check out our article on brewing with 120 volts.

Materials needed

  • One 4x8 sheet of R-3 foil faced polyisocyanurate insulation board
  • One small roll of foil faced bubble wrap.
  • One small roll of foil HVAC tape

Tools needed

  • Straight edge
  • Sharpie marker
  • Scissors
  • Utility knife


  • Place the kettle on the insulation board and trace separate 3 circles, using the inner curve of the kettle bottom as a guide. Cut the circles with a utility knife. Stack them on top of one another and tape together with foil tape.
  • Cut a piece of bubble (using scissors) wrap that measures 45" long x 16" tall.
  • Also, place the lid right side up (like you would normally place it on the kettle) on the bubble wrap and trace the inner circle, under the lip of the lid, with the sharpie. Cut the circle with scissors.
  • Attach the sheet to the kettle using foil tape, cutting holes for bungs and handles. Attach the circular piece of bubble wrap to the lid, using foil tape.

Once insulated, and with the lid resting on top of the kettle, using only the hop basket to provide an opening, a full, rolling boil will be achieved.

Kyle Brown is the owner of Clawhammer Supply, a small scale distillation and brewing equipment company which he founded in 2009. His passion is teaching people about the many uses of distillation equipment as well as how to make beer at home. When he isn't brewing beer or writing about it, you can find him at his local gym or on the running trail.

  • Outstanding. I appreciated all the help from emmet.
    I assembled the system without difficulty. Yes, I did a few modifications, adding a sight glass to watch the wort as it flows out of the pump. my old 40 plate chiller (my old system burned out—won’t say the brand), a couple of right angle stainless steel angles.

    Yeah, I could have bought the basic system, but I really like to have a few extras. You never know…😉

    Can’t wait for my first brew day with this system.,

    Posted by Tristan on October 18, 2023
  • What is the size of the port for the heating element? 2"?
    I already have a 5500w/pid controller 240v system and would want to use it so need to know size?

    Posted by Dan on June 24, 2020
  • I’d like to try the insulation part on my kettle, and I think I’ve found the right Foil, but I am not sure the fooil will withstand boiling temperature. Are there ones that don’t? Can you Recommend A Brand or Kind?

    Posted by Markus on July 22, 2019
  • What is the max grain bill i can use with this and still achieve 7.5 gallons pre mash

    Posted by Chris on June 27, 2019
  • Is the chiller that efficient that it only needs the one pass to cool to pitching temp? Or do you recirculate the into the kettle until it reaches the correct temperature?

    Posted by George Reinhart on April 23, 2019
  • Can you use a induction plate in conjunction with the element to reach boil faster

    Posted by John o on April 11, 2019
  • Is a 220 Volt version available? Maybe one that just plugs into my dryer outlet? I live in the states and see where this would eliminate the issue of insulation or worrying about getting up to temperature during the winter months. I like the concept of your product.

    Posted by Johnny on March 01, 2019


    Posted by Rob P on July 09, 2018
  • system ordered! I cannot wait for it to arrive. brew club dying to put it to the test! to answer a previous question, i see no reason that you could not do high abv beers with this setup, looks like there is plenty of room for large grain bill and adding a little sugar or honey to the boil always kicks up the fermentable sugar which yields a higher abv. hoping I get mine soon to still enjoy some sumertime brews on it. getting tired of brewing on my old propane system.

    Posted by Joe S on June 14, 2018
  • Hello, I am Considering your Clawhammer Brewing – Version 2.0 for an indoor cold weather Electric brew system. I have not found reference of the max gain bill recommended? With my current propane 3 barrel (Keggle) system I prefer to brew from 6% to 10% beers and would like to know what to expect from your system. Also do you ship from Colorado or Asheville, NC? Noticed your YouTubes were recorded in Asheville.

    Posted by Joe G. on June 05, 2018
  • I’ve brewed with my kettle about 4 times. I live in Florida at sea level and I’ve never had trouble reaching a vigorous boil. I haven’t done the foil wrap yet but I just wrap mine with a couple towels to hold in some heat. Works great. Very happy I purchased one of these. Makes brewing so much easier.

    Posted by Michael on May 14, 2018
  • I was hoping you would go more in depth in the altitude statics. I moved form CO to OR 6 months ago and was wondering if I would need to insulate. Wish i would have known about ya’all when I lived in greenwood village :D

    Posted by Dino on April 09, 2018

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