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Bulkhead for Cooler style Mash / Lauter Tun

Monday, January 12th, 2009

If you are converting a cooler into a mash / lauter tun this guide will show you how to install a bulkhead and ball valve. On the outside of the cooler, a ball valve attaches to a bulkhead. The bulkhead passes through the wall of the cooler. On the inside it connects to the manifold or braid so the wort will drain in a uniform fashion, with the flow controlled by the ball valve. Nuts and washers on either side of the bulkhead pipe (called a pipe nipple), compress against the walls of the cooler and form a water tight seal. Be warned, this is a fair bit of work to get done and may require several trips to the hardware store.

The bulkhead looks awesome when it is installed. It is something you can be proud of. The first time you open the ball valve to drain wort it is exhilarating, like that first ever sip of home brew. Your friends will be amazed by your dedication to the art.

The finished product:
mash tun ball valve

mash tun bulkhead inside

The first step is drilling the hole in the cooler. For a 1/2” nipple make a 3/4” hole.

mash tun bulkhead inside

In this design I am not using nuts to tighten down the washers. By choosing a very short nipple, the ball valve and the copper converter act like nuts compressing the washers against the walls of the cooler. I added some silicone sealant underneath the washers and inside the opening before assembling, then wiped away the excess after tightening.

mash tun bulkhead inside

Test assembled:
mash tun bulkhead inside

You will need to improvise based on what is available at the hardware store. The hardware guys will look at you like you are nuts when you try to explain what you are doing. A quick note about metals, I would not use anything but stainless steel, copper, or brass for the bulkhead. Palmer’s book How To Brew, has a lot of great information about using metals in the brewery.

On the end of the ball valve, you can convert to vinyl tubing easily with a barbed hose fitting.

3/4” hole saw, spade bit or forstner bit
Medium size crescent wrench
Channel locks

Materials outline:

Ball valve – accommodating 1/2” pipe, stainless steel or brass
1/2” brass or stainless steel pipe nipple, short as possible for your cooler – usually 1”
2 stainless steel washers
Rubber washer for outside
Pipe thread to copper converter
Silicone sealant

One place you can get the parts online is They are expensive, but this site has everything under the sun, including stainless steel parts.

There is one alternative to the bulkhead approach if you are using a cooler. Some people siphon wort through an outlet in their manifold. I find siphoning to be a clumsy approach. The wort is HOT (around 165 F) so you don’t want to be handling it. I have also seen plastic valves instead of the copper ball valve which attach to a hose.

This site has a related article on how to build a copper manifold for this cooler.

You are welcome to ask questions by commenting below.

  1. 14 Responses to “Bulkhead for Cooler style Mash / Lauter Tun”

  2. I recently sought out to do something similar. Unfortunately my donor cooler has very thick (1.5″) walls. I started with the short nipple similar to yours, but the threads didn’t clear both sides.

    The next size up (2 1/2″?) will clear the wall, but I’m worried if I’ll run out of threads before tightening down enough.

    I suppose if I went too big, I could improvise with additional washers, or possible tap additional threads into the smooth portion of a longer nipple.

    Last thing I want is a leaky mash tun.
    Any suggestions?


    By Sean on Jun 18, 2012

  3. Stainless steel washers will do the trick just fine!

    By Larry on Jun 19, 2012

  4. Perfect! very helpful thank you.

    By Dan on Jul 5, 2012

  5. so when you say 1/2″ diameter nipple for a 3/4″ hole is that 1/2″ ID 3/4″ OD? Or is it 1/2″ OD and it has to squeeze in?

    By Dan on Jul 14, 2012

  6. It is 1/2″ pipe, which is the inside diameter, and that is approximately 3/4″ thick on the outside. Makes for a tight fit, but some silicone sealant is needed too. I’d measure everything you buy to make sure you are cutting the right size hole.

    By Larry on Jul 15, 2012

  7. Great thanks. I thought that I had the same cooler you use here, but mine comes with a spigot that I had to remove, and the existing hole is a bit bigger… might have to get some larger piping and such. this hole is 1.5″. I suppose I couldn’t rely on just the washers, it still needs a snug fit

    By Dan on Jul 17, 2012

  8. Or drill on the opposite side and leave the build in one closed (or better yet, seal the built in one shut).

    By Larry on Jul 18, 2012

  9. Ok, trying to figure this out, but I am trying to do this without welding or soldering. Your bulkhead connects to the elbow on your manifold just by sliding on? I guess all I need now is a special copper elbow/S bend…

    Thinking about using a hose barb on the inside end of the bulkhead, and then a short foodsafe rubber tubing piece to connect to the manifold… Not sure how well the tubing connects to the copper manifold, and I was hoping to use all metal as you’ve shown here…

    By Dan on Jul 24, 2012

  10. Correct, the manifold slides over the bulkhead for easy dis-assembly. It doesn’t need to be air tight, just needs to allow the fluid to drain. I ended up cutting a small slit in the bottom of the inside copper piece that screws into the manifold. This allows me to drain the mash tun with less tipping.

    For other ideas, google for ‘bazooka screen’. There are lots of examples of those out there, you can probably connect that directly to the manifold.

    By Larry on Jul 25, 2012

  11. Awesome. Just wanted to say thanks, I finally got this together. A piece of advice everyone, keep in mind that the spigot is above the bottom of the cooler so you will need a short copper ‘s’ bend or tubing to make the dive down an inch or so (as can be seen in Larry’s manifold article, he used a tee and an elbow) to reach flush with the bottom. Thanks Larry!

    Also, here’s a good kit for most standard horizontal coolers. If you don’t want the satisfaction of slappin your own together ;)

    By Dan on Sep 13, 2012

  12. Shouldn’t the rubber washer go on the inside (liquid side) to make a better seal?

    By Brian Haley on Jun 9, 2021

  13. Brian, I believe you’re correct, but I’m not 100% sure on that. I *think* our mash tuns (10 gallon cylindrical cooler style) have washers on both sides of the valve, inside and out, but I’ll check the next time I’m at the brewhouse.

    By Jim Vondracek on Jun 10, 2021

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  2. Jan 29, 2009: Building a Mash Lauter Tun Copper Manifold | Brewer's Friend
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