Since I've been getting into brewing my own beer lately with Scott, naturally we started small with extract kits and then decided to dive right in with the more experienced process. This means to go to all-grain brewing where we need to use a mash tun. A mash tun is basically a vessel that combines the grain and hot water for a long period of time to extract the sugars from the grain.

Looking around on the internet, pre-made ones can be a little expensive, but there are a bunch of people online that are just creating their own. Christi and I have two reg igloo coolers, both without spigots on them, and have always wanted to get rid of these and get ones that have a drain on the end. Since I have the cooler, and I'm a DIY type of guy, I just dove in head first.

Looking at what others have done online, most use a manifold in the bottom to suck the water out. Basically it's a weaving of CPVC (so it can withstand more heat than PVC) with a bunch of small slits in the bottom so only the water passes through and the grain doesn't get stuck. Knowing this, I figured that 1/2" sections of CPVC would be wide enough for the water flow.

To connect the inside to the outside, we need to drill a hole. Since our inside connection is 1/2", a 3/4" bit was the absolute perfect size to use. Obviously, start small and work your way up since you can always expand it, but you can't ever make the hole smaller.

The toughest part was figuring out how I would drain the water, while connecting to the CPVC inside the cooler (without producing a leak). I bought a 1/2" ball valve, 1/2" female barb adapter (to drain the water on the outside), 1/2" brass nipple and a 1/2" CPVC female adapter to connect everything together.

In the picture above, it goes (from left to right): Barb -> Ball Valve -> Nipple -> CPVC Adapter. Make sure when connecting everything to use some teflon tape for secure connections. To get a secure, water tight fit, I used a rubber washer for garden hoses. I knew I needed something of the sort, and in my head, this seemed to be the best fit .. and it was.

The final step was creating the CPVC structure that you see in the top picture. Basically I cut 4" sections at a time, with a Dremel drill, and then used the same drill to create all of the tiny slots in the bottom.

Once everything is assembled, the last thing to do is pray that the water doesn't leak out. Everything is always perfect in your head until you actually try it. Luckily for me, I filled up the cooler with about 130° water and it all stayed on the inside. The last modification that I need to do is add some sort of weight inside my back piece of the manifold so that it doesn't float up when water is in there.

Check it out, everything magically worked and only took a couple of hours to put together: