Reflectix Insulation Jacket for your Mash Tun

Do you want to make your mash tun or electric kettle look like it’s been prepped by SpaceX and give it some good thermal characteristics?  Read on…
Sorry if I offended both SpaceX or NASA employees in one statement.

Difficulty: level_5

This is pretty easy.  It just requires some simple measuring, cutting and taping.  The patience portion of this may not be so easy depending on how good you are at measuring, measuring, calculating, measuring, measuring, marking, checking, measuring and cutting.

Time Required:

maybe an hour at the most.  Depending on how meticulous you are and how many do-dads are sticking out of your mash tun.


In my last post, Mash Tun Insulation Comparisons I ran an experiment on various forms of insulation for your mash tun.  My platform was the new Brewer’s Edge Mash & Boil.  Even though the jacket was made specifically for the Mash & Boil, I’m also going to lay out how to measure out your Reflectix insulation jacket.



Tools/Materials Required:

  • Reflectix
    • I purchased a 24 inch wide x 25 foot long roll for mine.  It is about enough for 6 layers , plus lids on a 12 inch diameter mash tun.  I’m only making 3 layers here.

  • Reflectix tape
    • Any other HVAC metallic tape will serve the same purpose
    • I just chose the Reflectix brand, because it didn’t have any writing on it.

  • High temp hook and loop
    • The normal Velcro brand adhesive only listed something up to 140 degF.  Since I was going to possibly be boiling with mine on, I wanted to find something rated higher.  This brand (although pricey for what you get) is rated up to 212 degF (100 degC)
  • Utility knife, get a fresh blade.
    • Believe it or not, the Reflectix dulled a blade from cutting 2 jacket’s worth
  • Long straight edge (great cutting guide) or tape measure

Method /How it’s made:

Here are the basic principles of measuring out a jacket for your mash tun.
  1. Choose a reference start location for your measurements, both in height and distance around the kettle
    1. You’ll want to choose something that you will want to stop and start at (spigot, sight glass, etc)
    2. I chose the spigot for the perimeter and the top lip for the height
  2. Try to sketch out what the jacket will look like rolled out with windows for all of the obstacles (look at my provided template)
  3. Remember, it’s easier to remove material than add, so as they alway say, “Measure twice, cut once!”
  4. When adding an additional layer, remember that the cutout locations will move further from your reference at each layer, due to the additional diameter added with each layer.
    1. For the Reflectix, it averages out at about 0.225 inches thick, so here is quick table that shows the amount of additional length to add for each layer length to just make it around.  If you want to add a tab for velcro, I’d use about 2 additional inches as I did.
    2. The formula for this addition is: 2*Pi*0.225*(layer number)
  5. 025-Layer Offset Chart
  6. Then for each cutout, it will be a ratio of the table above, depending on how far around the circumference it it.
  7. In all reality, you might outsmart yourself with the math, so there is no shame in just doing it all by hand.  Just go one layer at a time, then tape it all together when you are done.
  8. For the lids, I just set the lid on top of the Reflectix and traced around it with the utility knife.  Then I just cut a little tab to go through the handle on the top.
  9. When you are done,  you can simply tape all of the ends together to make it nice and neat.  I chose to just tape the very ends, since on the curve the stiff aluminum tape was going to look pretty wrinkly

Completed Jacket:

Here is the dimension scheme for a 3 layer Reflectix jacket for the Brewer’s Edge Mash & Boil.  Mine sits just on top of the display panel and just under the top lip.  I also rounded dimensions to the nearest 1/4 inch to make measuring and cutting easy.
025-Reflectix Insulation Jacket
The hook and loop was pretty straightforward
I didn’t want to mess with finishing all of the edges, so I just picked key areas.  I can always go back and add it if necessary.
025-Finished Edge
And here is the completed Reflectix jacket
025-Completed Jacket

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5 thoughts on “Reflectix Insulation Jacket for your Mash Tun”

  1. Do you think it’s worthwhile to use this stuff as fermenter insulation? With the same basic approach, one could make basically self insulating fermwraps.

    1. yea, I don’t know why it wouldn’t work equally well for fermenter insulation. I like the name too 🙂

    1. Thanks! The brand of the hook and loop is “Coil n’ Wrap”. It appears they cater to the RV crowd.

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