kick-a$$ fermenter

[camiller]

If the plastic is HDPE like I think, you will have a problem with oxygen permeating through the walls. I would get the beer out of there as soon as primary is over so you don't get any oxidation. Active fermentation will probably scrub out any oxygen that gets through, but once it's over, you risk staling of your new beer,

I got my Oatmeal Stout in one and Ed's devils-brew is the other.... for my stainless Primary's I just leave them in Primary until they are done... with the Aqua-Tainer I will likely move to a corny-secondary after 7-10 days.

I'm assuming ( I'm normally wrong) that you are doing this because you have the fear of oxidation? I am by now means experienced in brewing, but it seems that the whole oxygen permeability idea with plastic isn't very plausible.

Now this is just me thinking out loud here, but it seems that if you have liquid in a container and there is oxygen in the room it still won't be able to get in. It seems to me that the air would be equalized and unless somehow the aquatainer started sucking in air I don't think oxygen would necessarily flow through the brew.

Basically what I am saying is in my mind the oxygen permeability fear is hogwash. It is like when a car gets submersed in water, the pressure inside the car is less than outside in the water, so water will attempt to rush in in order to equalize it.

For the record I left my Red ale in the aqua tainer for 3 weeks and around 4 days and I tasted one after a week in conditioning and I couldn't notice any hints of cardboard or off flavor, but if you wanted to secondary after 10 days that would be fine too.

You'd think, but that's not how it works. If you have a permeable container that's pressurized with CO2, oxygen will continue to enter until the concentration of O2 inside matches that outside (even though the total pressure inside is much higher than outside).

It's called "Dalton's law" or "the law of partial pressures" if you want to google for more info. 1st semester college physics covers it.

That said, I think the oxygenation concerns are overblown simply because the level of permeability is tiny (and probably dwarfed by the exchange even at a well-sealed neck).

All of that not withstanding, the rate of o2 exchange through the water in your airlock and through the rubber stopper in a carboy is greater than the o2 exchange through HDPE even with the large difference in relative surface area. There was a good thread in April in the Brew Science forum -- https://www.homebrewtalk.com/f128/oxygen-uptake-plastic-fermenters-112662/

 

[lmg95]

You'd think, but that's not how it works. If you have a permeable container that's pressurized with CO2, oxygen will continue to enter until the concentration of O2 inside matches that outside (even though the total pressure inside is much higher than outside).

It's called "Dalton's law" or "the law of partial pressures" if you want to google for more info. 1st semester college physics covers it.

That said, I think the oxygenation concerns are overblown simply because the level of permeability is tiny (and probably dwarfed by the exchange even at a well-sealed neck).

ok so the power is out at work and i can't get into my lab so i did a little O2 permeability calculations... without going into too much detail about the units, I got a value of .0012 grams*meters (couldn't figure out how to get rid of the last unit of meters)

This value is the accumulated amount of O2 based on 3 weeks in a typical 7-Gal HDPE bucket(highest O2 permeability. Now keep in mind this is also based on pure O2 and we know that air is only 21% O2 so I tend to agree that O2 permeability is basically BS.

 

[Redbeard5289]

I got a question,

Could one use the blue 7gal Aqua-Tainer for a 2nd fermenter or perhaps a bottling bucket?

It seems to me that if you use it as a 2nd fermenter or a bottling bucket you wouldn't have to worry about the krausen getting to the top and becoming a problem come cleaning time.
I was thinking of getting one for a bottling bucket since I am sharing a bottling rig with my neighbor and we both are looking to bottle this weekend together but we are both short on time available. Thought I could save time if we didn't have to share a bottling bucket.
Just curious as to what your thoughts are...