Mash / Lauter Tun Problems

[small_apt]

I'm using a 5 gallon Rubbermaid Victory drink cooler with a stainless steel, domed false bottom as a mash / lauter tun. The false bottom is the same as the one found here: False Bottom.

I'm finding that at temperatures above 120 or so, the heat of the water causes the the plastic bottom of the drink cooler to balloon upwards, going from flat to concave down. As this happens, the bottom of the drink cooler comes into contact with the inlet valve on the bottom of the false bottom, greatly restricting liquid flow. As you can imagine, this doesn't help the sparging process.

Has anyone run into this? If so, what did you do? I'm thinking of running a bolt through the bottom of the cooler to prevent everything from ballooning upward, using rubber washers to prevent any loss of liquid.

 

[outside92129]

The plastic is going to expand whether try you restrain it or not. The easiest way for it to deform is upward, but it could go downward or push out the sides.... what if you slot the pickup tube (or put a hole in the side) so that cannot be blocked from the bottom? Or maybe just put a small piece of SS wool under it?

 

[airdog_47]

Or I would go get some 3" stainless steel bolts and make some legs to lift up the false bottom to a level above you ballooning. I know what you mean, on my 10 gallon tun the sides balloon inwards.