Fermonster lid cracking

I love Fermonsters but I’ve had two lids now crack on me. The cracking occurs horizontally along the seam where the flat surface at the top of the lid is “welded” to the side of the lid. The cracks are about 2 inches long and are clearly manufacturing defects. Has anyone else experienced this?

Google Photos

Just bought the 7 gallon and it arrived today.  I hope mine doesn’t crack!  I wonder if there is a similar lid available that works?  What about that Thin o-ring for the kid, how the heck do you get it to stay in place long enough to screw the lid on…is it even necessary?

Replacement lids aren’t expensive (~$4), but shouldn’t have to buy one. Arg. The o-ring is important, don’t leave it off. For me, easiest thing is pushing the ends of the o-ring into the depression first in a plus-sign pattern, i.e. center the o-ring on the depression and then push in the top, bottom, left, and right sides. Once these four “corners” are in, it’s easier to push in the remaining stretches.

I don’t have a Fermonster, but I’ve surely experienced plastic jar lids breaking just like that, as a result of tightening them down too far.  The threaded collar will keep going down the neck of the jar – remember how much mechanical advantage that little inclined plane gives – until the neck just pops through the flat top.  It’s not a manufacturing defect, it’s physics.  I’d think the o-ring is your friend:  it will give a good seal without over tightening the lid.  Stop when it’s just moderately finger-tight.

I have used Fermonsters for almost every batch, and I had one lid crack.

You’re likely tightening the lid too much, which is almost required to get a good seal out-of-the-box.

Apply a little keg lube  (food-grade petroleum jelly, basically) to the o-ring, and you won’t have to tighten the lid as much to get a good seal.  You will have to spend a little more time cleaning up between batches, but not as much as a special trip to the brew supply place.

I haven’t lost a lid since I started doing this.