Sealing a 20G kettle lid for "ferment in a kettle." Method? Material?

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Baglorious

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I want to do 15 gallon (finished) batches. Sure wish someone would market a stainless bucket-style 18-20 gallon fermenter with at least a somewhat conical/domed bottom that would fit in a kegerator. Like a bigger SS Brewbucket or Spike Flex. But no one does. :(

I own a Blichmann 20gal G2 kettle/mashtun. Blichmann offers teflon gaskets (for about $5) to allow the diptube to rotate. Could seemingly work as a big stainless fermenter that could do the job. Just need a satisfactory method to seal the lid for (non or minimally pressurized) fermenter use.

The Anvil FIAK kit/gasket is my inspiration, and I've already checked with Anvil/Blichmann, and the gasket for the Anvil FIAK is fitted for the Anvil kettle only. Also... I don't love the idea of silicone, as it has (seemingly unacceptable?) oxygen permeability for use on a fermenter, particularly in a gasket the size of the kettle rim. Not trying to overthink this, but if I'm going to do it, I'd prefer to do it as effectively as possible.

The Blichmann lid (from a G2 kettle) has a nice inverted "channel" around the edge that sits on top of and cups the kettle rim.

If I do use silicone, I know that the food grade silicone sealant (aquariums) is widely available. I could probably run a bead in the channel of the lid, perhaps heat it lightly with a heat gun so that it "flows" level and partially fills the channel.

However, I'd prefer Buna-N or EPDM... something along those lines.

One idea: I've looked extensively at the (FDA grade) Buna-N and EPDM products at places like Grainger and McMaster. There are adhesive backed strips in various thicknesses, like 1/16", 3/32," 1/8" that come in strips 3 feet long. The smallest width they have is 2"... but my thought is I'd cut it (with a straight edge and an x-acto) to make a long strip of the correct width. (Unsure on whether Buna-N or EPDM would be preferable.)

Second thought: Get a 5' piece of food grade Buna N or EPDM tubing of proper diameter (probably around 5/16" ID?) and slit it along its length, and just wrap it over the top of the kettle rim. (I'd figure out how to mate the ends of the tubing... or just a dab of keg-lube each time I use it.) This second idea is attractive, as I could theoretically (easily) take the gasket on and off the kettle rim.


Final bit of info: I'd likely just place two or three weight plates (about 10-15 lbs worth) on the lid when using this as a fermenter. That might supply enough weight on the gasket that I could push the beer out with a couple pounds of pressure. (I'm well versed in tinkering, have parts, experience, and will not blow up my brew-cave.)



Anyone have good success making a Buna-N or EPDM gasket for a 20 gal kettle lid? Or better ideas? Material recommendations?

If so, please share, and thanks in advance.
 
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It seems most conical have silicone gaskets...


Yeah... that seems to be the case, despite the claims/concerns about the oxygen permeability of silicone.

I've also read on the internet (where lots of people know all sorts of things) that it is a shame/travesty that homebrew manufacturers use silicone gaskets in fermenters. I wonder, in pro fermenters / brite tanks (the big ones)... what the gaskets are made of. If the industry uses silicone, I'd say I'm worrying about it too much.

I'm also beginning to think that, if I do this... I will use the kettle fermenter as a (shortish) primary fermenter... and transfer my to a secondary as soon as the most vigorous fermentation is done. I could probably put just under 15.5 gallons in the secondary while fermentation is finishing (but after it slows substantially), without that fermenter's lack of headspace being an issue. Fermentation would still be occurring to take up any oxygen that crept through the silicone in the primary. My secondary fermenters are SABCO keg-based fermenters with Buna-N gaskets... so for anything that is conditioning for the fermenter for any significant period of time, I'd be all set.

Still looking for advice anyone else might have! (Doesn't look like a topic too many people are concerned about, heheh.)

Thanks in advance!
 
Buna-N has low permeability if you can find an o-ring large enough. Just make sure it is food grade.
 
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