Domed False Botton in a Square Mash Tun

[Powers]

I built a mash tun a few years back and used a 10 gallon Coleman drink cooler (shown below) that I picked up super cheap. Because the cooler was not round, I just used a stainless steel braided coil as a filter.

Having brewed on this system for a few years, I now realize no matter what I do, my efficiency is never better than 65%.

I believe a false bottom would greatly improve my efficiency, but I don't want to get a whole new cooler just so a round false bottom will fit. But it seems a domed false bottom would still work, as it just lays in the bottom and doesn't need to be tight against the sides. The inside dimension of the cooler above is 12" x 12", so I anticipated getting a 10" domed false bottom to lay on the bottom. Can anyone confirm whether this appears workable? I have no experience with false bottoms at all, so any input would be greatly appreciated!

 

[rcrabb22]

I think 1 problem will be how to stop it from moving around when stirring the grain at dough in.

 

[Powers]

Good point, hadn't thought of that. I have a 14" flat false bottom for my boil kettle that I never use, and it came with tubing to put around the edges. Perhaps I could slide that tubing on to help it from moving. But, then again, maybe that wouldn't do much....

 

[rcrabb22]

Perhaps a rigid copper tube to connect it to the bulkhead but still might not be enough.

I think some stainless steel studs through the cooler floor and cotter pins might do it if you could seal them in with food grade silicon to prevent leaking. I actually did this same mental exercise a while back and I didn't come up with a workable solution at that time.

 

[Powers]

i'm stumped. the rigid tube could improve the situation, but still not completely fix it.

i did a quick search for the steel cotters and pins, but didn't see anything that could be secured very well to the cooler.

on my budget, a new cooler and false bottom are out of the running, so i guess i'll have to eat my poor efficiencies for awhile longer until i can get a little more cashflow into the brewery...