How to Build a Mash Tun – Start All Grain Brewing!


What’s a Mash Tun?

A mash tun is a container that holds grain and warm water.  The warm water activates enzymes in the malt and converts complex carbohydrates to yeast-friendly simple sugars.

A mash tun can be as simple as a bucket. Many homebrewers convert coolers to mash tuns.  Those have the advantage of insulation. That insulation helps maintain a steady temp throughout the mash process. Kettles are also regularly used as mash tuns and there are also some purpose built stainless mash tuns. An example of that is Ss Brewtech’s InfuSsion Mash Tun.

Components of a Mash Tun

  • A container – Examples: bucket, cooler, kettle, keggle or a purpose built vessel
  • Filter device/mechanism – Examples: false bottom, bazooka screen
  • Ball valve and tubing
  • Optional – sparge arm, thermometers

Coolers to Consider

A key feature to look for when considering a cooler to convert to a mash tun is a built in drain.  It’s possible to drill a hole in some coolers, but it’s generally, much easier if the cooler has a drain.


Mash Tun Conversion Kits

False Bottoms

Ready Made All Grain Brewing Setups

Popular (and Simple Design) via Denny Conn and the AHA

How to Build a Mash Tun

This setup is based on Denny Conn’s great design.  Denny is a legendary homebrewer. Among other things, he is the co-author of Experimental Homebrewing and the keeper of Wyeast 1450 Denny’s Favorite 50.  Check out Denny’s Author Page on Amazon see more of his books.

See the AHA’s Article on this: How to Build a Mash Tun – via the American Homebrewer’s Association


cln_img_0353Taking mash temp with my Thermapen Mk4.  Notice the backlit, rotated display.

Or… Brew BIAB Style

BIAB uses a low cost cloth bag as a filter.  This allows you to brew all grain beer using a single kettle.  It’s easy and cheaper to get started vs a dedicated all grain setup.

Do You Need a HLT?

A hot liquor tank is a container that holds hot or warm sparge water.

Many of the cooler all grain system systems on the market include two coolers.  One functions as a Hot Liquor Tank (HLT) the other as a Mash Tun (MLT).  If you’re a batch sparger, you may be able to get by with one cooler if by using a spare kettle for your hot liquor tank (HLT).  When I first went to all grain, I used my 5 gallon extract kettle to piggy back the first runnings.  Doing this allowed me to temporarily use my boil kettle as a HLT.

It worked something like this…

  • Heat strike water in boil kettle
  • Drain strike water into cooler mash tun and mash
  • Heat sparge water in boil kettle
  • Recirculate and drain first runnings into 5 gallon extract kettle
  • Empty sparge water into cooler mash tun
  • Dump first runnings from 5 gallon kettle into boil kettle
  • Recirculate and drain second runnings into boil kettle
  • Boil!

Obviously, this is batch sparge method.  This method would not work with fly/continuous sparging.  If you are fly sparging… you need a dedicated HLT.

Having a dedicated HLT is preferable, but this piggy back method got me started in all grain at a reasonable cost until I could pick up another kettle.

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Check Out These Related Reviews

Everything All Grain!

Our resource post on all grain is the source for everything all grain!

Make sure the components you use are compatible and rated for your intended application.  Contact manufacturer with questions about suitability or a specific application.  Always read and follow manufacturer directions. toppost:makingamashtun tag:tpr

9 thoughts on “How to Build a Mash Tun – Start All Grain Brewing!

  1. David K

    How is the street elbow attached to the false bottom? I tried to upgrade mine last night with a street elbow and had to rig it together. Is there some sort of hollow male threaded bolt that screws into the elbow clamping it down to the false bottom?

  2. EG

    I have the same exact cooler and conversion kit, and my dead space is around a pint (not a quart), as long as I don’t lose siphon. When you drained it did you attach a tube that emptied below the level of the valve?

    1. admin Post author

      Interesting. Thinking about the siphon effect… I did use a tube when doing this test. It had a drop of 2 or 3 feet (from my table to a keg sitting on the floor). In the interest of getting a reasonable and realistic result, I did not tip the cooler in any way. That would probably help to get more liquid out. That’s something I would probably do on most brew days. Beyond that.. I’m trying to think of what the difference would be.

        1. admin Post author

          Great question David. I’ve added that to the review. I’d say 1/4″ gallon would be a great figure.


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