Capturing CO2 during active fermentation

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TheSumOfAllBeers
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Capturing CO2 during active fermentation

Post by TheSumOfAllBeers » Mon Nov 14, 2016 3:52 pm

I want to prevent oxidation of beer in my conical, which is starting to happen now that I can crash cool.

I was thinking of putting a Tee connector in my blow off tube, rigged to an expandable bladder, to capture CO2 generated from fermentation.

Has anyone done anything like this? I could use a polypin, and some cheap valves. Anyone know if any build outs exist that do the kind of thing I am talking about?

AnthonyUK

Re: Capturing CO2 during active fermentation

Post by AnthonyUK » Mon Nov 14, 2016 4:10 pm

Can't you just purge it from a cylinder?

Secla
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Re: Capturing CO2 during active fermentation

Post by Secla » Mon Nov 14, 2016 4:10 pm

Teeing off would still trap air in the bladder. I would think something inline would work better so all oxygen would be pushed out from the system during fermentation

TheSumOfAllBeers
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Re: Capturing CO2 during active fermentation

Post by TheSumOfAllBeers » Tue Nov 15, 2016 11:53 am

Purging from a cylinder would work, but that's an expensive solution for managing headspace, unless you have other uses for that CO2 like keg dispense or dispense under pressure. CO2 capture is nice and low tech for my purposes.

If you let the bladder inflate and then squeezed everything out of it, you would purge most of the O2 out of it. Especially if you repeated it multiple times.

rpt
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Re: Capturing CO2 during active fermentation

Post by rpt » Tue Nov 15, 2016 1:53 pm

Do you really have a problem with oxidation when you crash cool?

AnthonyUK

Re: Capturing CO2 during active fermentation

Post by AnthonyUK » Tue Nov 15, 2016 4:10 pm

TheSumOfAllBeers wrote:Purging from a cylinder would work, but that's an expensive solution for managing headspace, unless you have other uses for that CO2 like keg dispense or dispense under pressure. CO2 capture is nice and low tech for my purposes.

If you let the bladder inflate and then squeezed everything out of it, you would purge most of the O2 out of it. Especially if you repeated it multiple times.
I 'bought' my 6kg cylinder a few years back which cost £22 with no deposit which is the same for exchanges. I wouldn't call it expensive but not free I suppose.
I just seems like a lot of effort with scope for it to increase risk.
If you're crash cooling in the conical wouldn't it be absorbing mainly CO2 anyway from the headspace?

TheSumOfAllBeers
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Re: Capturing CO2 during active fermentation

Post by TheSumOfAllBeers » Tue Nov 15, 2016 4:47 pm

The contraction of the headspace during cooling creates negative pressure that will suck in through racking/dump valves.

If I disconnect the blow off tube, the headspace will equalise by drawing in some atmospheric air.

So I am adding O2 to the headspace which can get into the beer.

The problem becomes more pronounced if I underfill the conical, or if I start to drop out yeast/trub or large dry hops.

I am not certain if oxidation is an issue, but I have only recently started crash cooling, and plan to do more of it in future.

McMullan

Re: Capturing CO2 during active fermentation

Post by McMullan » Tue Nov 15, 2016 7:22 pm

I used to purge 2ry FVs using CO2 from active 1ry FVs. Surprising how much CO2 is evolved during vigorous fermentation, so I think you could make use of it. Be careful not to contaminate your beer with another yeast strain, though. When I 'cold crash' it's done slowly over a couple of days or so, about 5*C a day. This way the yeast remain active enough to minimise what you're worried about, I think.

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