keg mash tun w/ false bottom problemo

[big tom]

Hey all I just converted my old boil kettle into a mash tun by adding a fermentap false bottom to it. I used it for the first time yesterday and had a major problem, it collapsed and is now warped. I have my mill set at .035, and recirculated the mash for the entire 60 min mash, and I then unsuccessfully tried to raise the mash temp to mash out for about 1 more hour, at the end of which the flow has slowed down substantially to just a thin stream. The grain bill was 33 lbs for a 10 gallon batch and after I ran everything off into my kettle I discovered the false bottom had inverted! It took quite a lot of force to get it back to the proper shape, and I tweeked it for a short time but it now will not sit flush with the bottom of the keg. What should I do? What setting do you think I should open my mill up to for a constant mash recirculation? I did get about 75%+ eff on a 1.082 beer which is pretty outstanding, but not at the cost of a $45 false bottom! What do you guys think?

My previous mash tun was a ice cube cooler w/ a copper slotted manifold. I never recirculated that one for more then 30 mins or so, and never had any problems with it.

[Grizz]

I would not change the mill setting yet. If you were able to recirculate then grain crush was not it. For the false bottom I would strip the fittings off of it. Then find something with a very close shape to the false bottom. Use a rubber mallet to flatten the edges back into shape against the item you found. I think the weight of the grain crushed the false bottom not the grain size. I would then find some copper cuplinks 1/2, 3/4 or 1 inch that will fit under you false bottom with out it lifting it up. This will not let the grain weight crush the false bottom. Try to set the cuplinks so that the open ends are pointing toward the pickup. Try it again with a smaller batch and see how it works. Good luck

[budrockdiesel]

I would not change the mill setting yet. If you were able to recirculate then grain crush was not it. For the false bottom I would strip the fittings off of it. Then find something with a very close shape to the false bottom. Use a rubber mallet to flatten the edges back into shape against the item you found. I think the weight of the grain crushed the false bottom not the grain size. I would then find some copper cuplinks 1/2, 3/4 or 1 inch that will fit under you false bottom with out it lifting it up. This will not let the grain weight crush the false bottom. Try to set the cuplinks so that the open ends are pointing toward the pickup. Try it again with a smaller batch and see how it works. Good luck

I am sorry but I have to disagree. I think it was the crush. Never underestimate the force of vacuum. If you took a 55 gallon drum, layed it on its side and opened a valve with out venting it, the thing would crumple up like a budlight can just from the vacuum.

[big tom]

Thanks for the tips on getting it straightened out Grizz, but I would have to agree w/ bud that the vacuum contributed to the collapse of the false bottom, at the end of the mash the flow had slowed to a trickle, and I think that did it.

Anyone have a suggestion of what to set my mill at? I am thinking about going to .045 and working my way back down.

[Henning1966]

Using a grant to do the recirc might help. That way you can control how fast the tun empties with a ball valve to keep it from compacting.

[big tom]

I'm considering that for sure.

[Mylo]

I bought one of those recently too. It was warped (slightly) when I got it (enough to not make complete contact with the keg bottom and let grain through). It took about 10 minutes with light taps from a ball peen hammer (on my drill press table) to get it back in shape. Go slow, or else it will just warp in the other direction.


Mylo

[animaldoc]

I have an old Schmidling fixed-roller MaltMill that has the gap preset at 0.045" and I get 75-85% efficiency (75% is a bad day ).

-- Animaldoc