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DIY: Making Your Own Cooler Mash Tun

Making your own mash tun out of a cooler is an easy process and ensures that your mash process is insulated and evenly heated. Here’s how to do it.

Jester Goldman Sep 9, 2016 - 7 min read

DIY: Making Your Own Cooler Mash Tun Primary Image

Making the leap to all-grain brewing gives you finer control of your recipes and can also save you some money on ingredients, but it does require special equipment. You need a container to hold all the grain while the starches convert, and you need a way to rinse the sugars from the malt. It’s a simple problem with a multitude of solutions. Some people use a brew-in-a-bag setup, which is fairly simple, but it does require some muscle. The more traditional path is to use a mash tun with either a false bottom or some kind of manifold. Here, I’ll show you how to build a mash tun from a 10 gal (38 l) drink cooler (pictured above).

Parts List

  • 10 gal (38 l) cylindrical drink cooler (Igloo or RubberMaid, for example)
  • Tapping hardware
    • Adapter: ½ in (13 mm) copper pipe to ¾ in (19 mm) FPT
    • Bottling spigot
  • Manifold parts
    • Three ½ in (13 mm) copper tees
    • Four ½ in (13 mm) copper end caps
    • About 6 in (15 cm) of straight ½ in (13 mm) copper pipe
    • About 6 ft (1.8 m) of ½ in (13 mm) copper tubing

Like any good DIY project, there are many paths to get to the completed project. This project in particular makes several design trade-offs. You could just use a stainless steel kettle as the vessel, but a cooler has built-in insulation, which will help to better maintain the mash temperature. Also notable is that a cylindrical drink cooler works better than a rectangular one because the geometry provides a good grain bed and efficient draining.

I’ve chosen to make the manifold from copper tubing. Other alternatives would be to make or buy a screened false bottom that fits the cooler (12 in/30 cm round for a 10 gal/38 l cooler) or to use a stainless steel braid as a filter.


  • Pliers
  • Plumbing torch
  • Lead-free plumbing solder
  • Flux
  • Dremel tool with a cutting blade
  • Pipe/tubing cutter

Build Steps

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