Igloo Cooler Mash Tun Conversion

DIY Igloo Cooler Mash Tun Conversion for All Grain Brewing
The below step by step procedure should give you all the information you need to build a cheap mash tun for all grain brewing.

Part List:

  1. 10 Gallon Igloo Cooler - You can get these coolers many places.  I got the one I used significantly cheaper on eBay but many other coolers can be substituted to build an effective Mash Tun.  I opted to used a round cooler but rectangle coolers can work well too.
    10 Gallon Igloo Cooler Mash Tun Conversion
  2. Cooler Bulkhead - I have seen other tutorials online with cheaper options but I have not had much success stopping the cooler from leaking with those so I spent the extra money and got a bulkhead that works really well.  Not only did it stop the leaking problem it also helped keep the mash from loosing temperature.  In previous designs I was typically loosing about 4 degrees during the hour mashing process.
    Igloo Cooler Buikhead
  3. Brass Barb x MIP Adapter (2) – You will need 2 of these for use inside of the cooler to connect to the Braided Stainless Steel (step 4) that will be used to filter the wort as it drains through the grain bed.
    Brass Barb MIP Adapter
  4. Stainless-Steel Braided Faucet Supply Line - I bought the 16 inch length so I had extra to use in the event I made any mistakes or needed to make any repairs.  During initial construction you will only need about half.
    Stainless Steel Braided Faucet Supply Line
  5. Brass Square-Head Plug - This will be used secure to one end of the stainless-steel braided faucet supply line.
    Brass Square-Head Plug for DIY Igloo Cooler Mash Tun Conversion
  6. Wire Ties (2) – These will be used to secure the steel braid (item 4) to brass barb MIP adapter (item 3) and to the brass plug (item 5).
  7. Teflon Tape – This will be used to wrap around the threads of the brass barb MIP adapter (item 3) that will be screwed into the cooler bulkhead (item 2).
  8. Ball Valve (1/2 inch) – This will be used to stop the flow of wort out of the cooler easily.
Igloo Cooler Mash Tun Conversion Installation Instructions:
Parts Lineup:
Step 1: Remove spigot from cooler
Step 2: Use hacksaw and cut braided steel.   Once you have cut a length that will fit inside you cooler make sure to pull out the plastic inner lining in the direction that does not un-braid the steel.  See image below.

Step 3:  Install Brass Plug into one open end of braided steel and fasten with a wire tie.

Step 4: Wrap threads of Brass MIP with Teflon tape.

Step 5 – Screw brass MIP (above) into Cooler Bulkhead.

Step 6 – Install Cooler Bulkhead into cooler from the inside.

Step 7:  Wrap the other end of the cooler bulkhead with teflon tape and then from the outside of the cooler secure the bulkhead with larger rubber gasket and nut.  Be sure to make sure the rubber gasket is against the cooler.

Step 8:  Screw ball lock valve onto end of bulkhead.

Step 9:  Screw the other brass MIP to end of ball lock to easily connect tubing for hot liquor or wort removal.

Fairly simple process that yields great results.  I’m sure there are cheaper ways of building something comparable so if you have any better options for parts listed above feel free to add a comment below or send me an email.  Enjoy your new mash tun and more importantly your homebrew!

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All Grain Oatmeal Stout

All Grain Brewing Oatmeal Stout Recipe – This Guy Oatmeal Stout

Original Gravity: 1.061All Grain Oatmeal Stout Recipe

Final Gravity: 1.020

ABV: 5.5%

SRM: 30°

IBU: 46.1

Boil Size: 6.5 Gallons

Batch Size: 5 Gallons


Grain Bill:


  • 60 Minutes – Chinook - Pellets – 11.7 AA
  • 1 Minute - Chinook - Pellets – 11.7 AA



I was extremely happy with how my Oatmeal Stout came out.  Before sampling the first thing you would notice was the nice creamy head and dark rich color.  Aroma coffee like as anticipated from the roasted barley.  When sampling you will notice a mellow bitterness and silky smooth texture that comes from the addition of oatmeal to the mash.  Chocolatey undertones are also very prevalent which also adds to the bitterness of the stout.  I will definitely be brewing this beer again.

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