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Mash Tun
Home > Gear > Mash Tun

So you want to brew your own beer from malted grain? A mash tun is an important part of the process. It is a vessel to hold the ground malt and water to convert the starches into fermentable sugars. Many homebrewers use coolers to mash in, because you want to hold the grain at a constant temperature for about an hour.

This is my second mash tun built using the same process. I upgraded from a 48 qt standard Coleman cooler to a 70 qt Coleman Xtreme cooler. The Xtreme cooler is nice for two reasons. They claim that it is better insulated than the cheaper ones, and the drain is very low, allowing for more thorough drainage. This mash tun using the stainless braid popularized by Denny Connso it is best suited for batch sparging.

Coleman Xtreme Cooler and parts for Mash Tun Parts

Braided Stainless Steel Water Supply line
3/4" Stainless Steel Washer
3/4" Zinc Washer(s)
1/2" x 1.5" Brass Nipple (You may need a longer nipple if your cooler walls are thicker)
1/2" Ball Valve
1/2" Hose Barb Adapter (1/2" Barb x 1/2" FIP)
Stainless Steel Hose Clamp
Teflon Tape

Make sure that the braided water supply line is actually stainless steel before you buy it. Some, though they look like stainless, are actually plastic, and will not work. I got all of my parts from Lowes, but I'm sure you can find the same things at any big hardware store.

These instructions should work for any cooler, but you may need to adjust the length of the nipple, or the number of washers if your cooler is different.

Next you'll need to take out the old drain hardware. On my cooler it was easy to unscrew the drain plug from the outside. You will need to save the rubbery washer that came with the cooler. Slide the rubbery washer to a little less than the half way point of the nipple. Around where the smooth part starts should be good.

The washers need to fit fully over the brass nipple. For some reason, the zinc washers fit over it well, but the stainless one didn't fit. I spent a couple minutes working on it with a rotary tool to enlarge the hole enough to fit.

Coleman Xtreme Mash tun Drain parts

Coleman Xtreme Mash Tun Lauter manifold parts The picture to the left shows how all the plumbing will eventually be connected.

Ball Valve -> Zinc Washer(s) -> Cooler Wall -> Rubbery Washer -> Stainless Washer -> Hose Barb Adapter

Leave the rubbery washer on the nipple and wrap the threads of the nipple with teflon tape. Put the stainless washer on the nipple up against the shoulder of the rubbery washer. Tighten the Hose barb adapter up against the stainless washer. Put the nipple through the drain hole from the inside of the cooler.

When I tried to insert it into the drain hole from the inside of the cooler, it would no longer fit. I had to enlarge the interior wall of the drain hole a little bit with a rotary tool

Coleman Xtreme Mash Tun plumbing

Coleman Xtreme Mash Tun Drain Ball Valve Put the zinc washer(s) over the exposed nipple outside the cooler and screw on the ball valve. Use enough washers so that the ball valve is tight and no longer rotates. I used two washers.

At this point, you may want to attach a 1/2" Male Hose Barb Adapter to the output of the ball valve. I will be using a special quick disconnect fitting, so I didn't picture it.

Cut the ends off the braided hose with a hack saw.

Carefully fold one end of the braid away from the hose.
Grab the hose with a pair of pliers and gently slide the braid off the hose. If you grab it and yank, the braid will tighten up on the hose like those Chinese finger traps.
Fold one end of the hose back on itself several times and crimp it down with a pliers.
Coleman Xtreme Mash Tun Stainless Braid

Coleman Xtreme Mash Tun Stainless Braid in cooler Finally, slip the open end of the hose braid over the hose barb and clamp it down with the stainless hose clamp.

Mash On!

Copyright © 2008 Stephen Small. All rights reserved.