70 Quart High Gravity Mash Tun

We found out pretty quickly that our 10 Gallon Mash Tun would not work for High Gravity or Large Grain Bill brews.  I told my brew partners that we would probably need a Coleman Xtreme 70 Quart rectangular cooler for our next Russian Imperial Stout.  Immediately, my brother-in-law pulled up a picture on his phone and with amazement declared, “I have that cooler in my garage!  I’m not even using it”.

Once he got home and measured it, we compared that to the measurements on the Amazon page for the cooler.  It was, indeed, the exact cooler for which we were looking.  Score!  It was missing a handle and, of course, since it had been sitting in his garage for a few years, was quite dirty.

I filled the bath tub in my guest bathroom with a hot water and Bar Keeper’s Friend mixture to soak the cooler.  In order to do this the easiest way possible, I removed the 4 screws that attached the lid to the body.  This way, I was able to soak both the cooler and the lid at the same time.

As I took it apart, I noticed two crucial things about the cooler.  The missing handle is on the same side of the cooler as the drain spout.  Easy fix.  The cooler lid will open facing the HLT.  This is the side we needed it to be on.  What does this mean?  We can leave the lid screwed in to the hinge once the cooler is assembled.


Now for the parts list:

Coleman Cooler Handle – $4.99

Home Depot:
1/2″ x 10′ CPVC Pipe – $3.55
1/2 in. CPVC CTS Slip Cap – $0.21 x 2
1/2 in. CPVC CTS Slip x MPT Male Adapter – $0.25
1/2 in. CPVC CTS 90-Degree Slip x Slip Elbow (10-Pack) – $1.97
1/2 in. CPVC CTS Slip x Slip x Slip Tee (10-Pack) – $1.79

Bargain Fittings:
Premium LONG Bulkhead kit for coolers – $25.94

Total Cost:  $38.91

Yeah, I was blown away by the price, too.  Of course, having the cooler already saved $70.

Pretty simple replacement for the handle.  It came with the two pins that hold it on to the cooler.  Remove the one pin that was left in the cooler, hold the handle in place and push the two pins in through the handle bracket to the handle.

Next remove the drain spout by opening it and rotating the cover clockwise to unscrew it.  The inside just pulls out from there.

I must admit, I did not plan far enough ahead and when the bulkhead arrived, I noticed that it was not long enough.  The bulkhead would not fit onto the nipple inside the cooler and the valve would not close all the way because it would hit the cooler wall.  I had to order the 2.5″ closed nipple that comes with the long bulkhead kit referenced above.  Now I have an extra closed nipple.  It’s not like I won’t find a use for that!

Here are the two nipples side by side.  You can see quite the difference!

Short Nipple:

Long Nipple:

And now the valve can close all the way.  The recess for the drain is pretty deep into the wall of the cooler.

Now that we have that installed, let’s move on to the new manifold for this Mash Tun, shall we?

Here we have all the pieces cut and laid out.
7 Tees
6 Right angles
2 Slip Caps
1 Slip to MPT Adapter
6 lengths cut to 3-7/8″
3 lengths cut to 5″
2 lengths cut to 1-3/4″
2 lengths cut to 5-3/8″
2 lengths cut to 9″
2 lengths cut to 9-7/8″

Not shown is the length of CPVC to connect the manifold to the Slip to MPT adapter as that had to be be figured out once the manifold was built and in place.

Now we drill the holes using a 3/32″ drill bit.  Send a bottle brush through these lengths of pipe to clean out any debris left over from drilling.

Since I wanted to do all the work inside, I used my Craftsman Handi-Cut hose cutters to cut the CPVC.  It worked like a charm.

I assembled the cross pieces using the 3-7/8″ pieces.

Put on the first side pieces using the 5″ sections:

The next cross piece and side pieces.  These are the 5-3/8″ pieces.

The last cross piece.  The open Tee will be used to connect the manifold to the bulkhead. The long side sections are 9-7/8″.

Short legs (1-3/4″):

Returns at 9″ and the caps.

I put the manifold in place to test the fit.   Then I measured the distance between the open Tee and the Slip to MPT adapter.  That length ended up being 8-1/2″

Cut the CPVC and put it in place.  ***NOTE*** This piece does NOT have holes drilled.

You can see the assembled manifold and all the drilled holes below.

Of course, I had to add my own touch to the cooler.  I mean, who wants a Coleman label on their brewery Mash Tun?

Now THAT’S what I’m talking about!  Of course, this was built before the logo and name change, but this can be fixed.

I still can’t believe the luck of being able to build a 70 Quart (17.5 Gallon) Mash Tun for under $50.  This one was less than $40!!

If you’re gonna brew, might as well Brew Happy.

6 Replies to “70 Quart High Gravity Mash Tun”

  1. For the bulkhead kit what did you select for the Valve, Inside Option, Hose Barb, and Extra Locknut options? Want to make sure I get the right thing.

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