Mash Tun Design

[bgarino]

I want to build a Mash Tun out of a Keg. What is the best design or any advise before I start. Thanks for the help

 

[Maxkling]

Cut off top, install false bottom and valve, install a thermometer, and wrap with foil insulation.

 

[Bobby_M]

If it's going to be mounted in a stand of some type, flip it over and cut the BOTTOM out and install the drain on the 2" flange which is now at the bottom.

 

[bgarino]

Bobby do you have any pics of the Mash Tun?? The Tun is going on a Brutus 10 clone so the fittings would be in direct contact with the burner. Wouldn't that be a problem??

 

[pickles]

Bobby's recommendation will only work for an electric set up. I have some pics in my signature line.

 

[Gwitz]

Bobby's recommendation will only work for an electric set up. I have some pics in my signature line.

I think you mean you cant direct fire with that setup, which is true but i dont see to many people direct firing their mash tun anyways.

My advice, having a bottom drain is absolutely the best way to go. You dont necessarily need to turn the keg upside down to achieve that. I did it for my mashtun, but i made my boil kettle bottom drained by simply welding a fitting into the bottom. Either way works, id probably recommend just cutting the top out and welding a fitting into the bottom, im sure you could do it weldless as well.

 

[JuanMoore]

+1 for bottom draining if possible. I direct fire my bottom drain HLT without any problems. I flipped the kegs like Bobby suggested above so that I could route the plumbing through the keg handle holes and not have to modify my stand. Plumbing it this way creates a small air bubble in the drain line, and in restrospect I wish I would have left the kegs upright and just modified the stand for bottom drains. I have to drain a few ounces as the tun is heating up to purge the air, which isn't a big issue, but it's still not ideal. I may re-route the plumbing and modify the stand someday, but it works well enough for now.

 

[Bobby_M]

I believe you could direct fire a bottom drain just fine. You'd never burn without the wort moving anyway. If you were really worried about it, you could just add a heat shield or block off burner tips that are directly hitting the tubing. No matter what the heat source, I'd never build a tun with a side drain again.

I often read that you can't direct fire such a setup but it's never been tested and verified to be a problem.

 

[JuanMoore]

I also reccomend buying the lid before cutting the top so that you can cut it to the exact size you need.

I often read that you can't direct fire such a setup but it's never been tested and verified to be a problem.

My testing has verified that it's not a problem, for me at least. I direct fire my bottom drain HLT every batch, and even though I use a HERMS I direct fired my bottom drain MLT once when I was having mechanical difficulties, and had no issues at all.

Edit: Disclaimer- I have only brewed once direct firing the MLT, and I'm unsure if repeated use would cause any issues, like caramelized wort build-up inside the plumbing. I do know that it worked well the one time, and that the direct fired HLT works well every time, but I can not verify that a direct fired MLT works well long term.

 

[orangehero]

Don't forget the tippy dump.

 

[pickles]

Direct firing doesn't burn the gasket on the tri-clamp fitting? That surprises me, but I have no actual evidence to refute it.

 

[Bobby_M]

Silicone is good for up to 600F and with wort running through it, it shouldn't get much over wort temp.

 

[JuanMoore]

Direct firing doesn't burn the gasket on the tri-clamp fitting? That surprises me, but I have no actual evidence to refute it.

My rig is way too ghetto for tri-clamps, just brass and copper plumbing parts with two silicone o-rings. Never had any issues. As Bobby pointed out, the liquid inside keeps the fittings relatively cool, and silicone has pretty high temp ratings (I've read conflicting numbers from 450F-750F). I was more worried about the seats inside the ball valves than anything else since I wasn't sure what type of plastic they're made of. I hoped they were PTFE since it's rated for similar temps as silicone, but whatever they're made of appears to be good enough.