Need an airtight bucket

[mpcluever]

Got a bit long there. TL;DR I need a 2-3 gal airtight container that I can mount bulkheads in.

I've got a 27 gal conical in an insulated cabinet with heat bulbs and an air conditioner for temp control. When I crash cool it from 68 to 40, the beer and air contract and it sucks the water from my airlock back into the conical.

I rigged up this airlock that solves that problem.

As it's fermenting, it comes into the top of the jar on the left, out the bottom to the bottom of the 2nd jar, where it bubbles out a hole in the lid.

The problem is that when I cool it, it contracts more than the half gal of water here, so it sucks all the water back into the first jar and then bubbles air back into the fermenter.

So far, this hasn't been a REAL problem, but this is unfiltered air and being a sealed cabinet, there's almost always a bit of mold growing in there somewhere. Also just sucking oxygen back into the fermenter isn't great.

I used 2 corny kegs, but it didn't suck anything back to the first keg. Air leak somewhere. I suspect the lid since those seal under pressure.
I used 5 gal homer buckets with the gasket lid and same thing. Air leak somewhere and it didn't suck any water over.

Anyone have any suggestions?

 

[whattheschmidt]

Does your conical accept pressure? what if you were to pressurize it to 5psi then crash cool it?

Just throwing out something, I have only crash cooled with a 5 gal batch in a bucket before.

 

[ThunderpantsBrewing]

These are great air tight buckets:
http://www.usplastic.com/catalog/item.aspx?itemid=24116&catid=626

 

[Stealthcruiser]

So, you lose no quantity of water, to the fermenter, during cold crashing, correct?

And all the "appropriate" fluid and air paths are submerged, when needed, during your processes, yes?

I would think that an air filter that filters the atmospheric "draw" would take care of your concerns............Unless I'm missing something here.