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General Category => General Homebrew Discussion => Topic started by: yso191 on January 12, 2017, 05:37:57 PM

Title: Volume of CO2 produced during fermentation?
Post by: yso191 on January 12, 2017, 05:37:57 PM
As a casual observer of the ongoing LODO discussions, I have come across the spunding topic.  I have always done a form of spunding, but I find myself wondering about a further level.

Specifically I'm thinking about connecting a sanitized keg to the fermenter in order to purge the keg of air, replacing it with the CO2 produced during fermentation.  Then of course, when fermentation is done, just switch the connector to the 'gas in' post and the drain the fermenter via the 'beverage out' post, and the beer never comes in contact with oxygen... I hope.  That all depends on whether enough CO2 is produced during fermentation to purge the keg.

Does someone know?
Title: Re: Volume of CO2 produced during fermentation?
Post by: a10t2 on January 12, 2017, 05:44:00 PM
Obviously it depends on gravity and minimally on temperature, but the average would be around 20 volumes of CO2 per volume of wort. You'd need a spunding valve on the receiving keg as well.
Title: Re: Volume of CO2 produced during fermentation?
Post by: The Beerery on January 12, 2017, 05:46:40 PM
As a casual observer of the ongoing LODO discussions, I have come across the spunding topic.  I have always done a form of spunding, but I find myself wondering about a further level.

Specifically I'm thinking about connecting a sanitized keg to the fermenter in order to purge the keg of air, replacing it with the CO2 produced during fermentation.  Then of course, when fermentation is done, just switch the connector to the 'gas in' post and the drain the fermenter via the 'beverage out' post, and the beer never comes in contact with oxygen... I hope.  That all depends on whether enough CO2 is produced during fermentation to purge the keg.

Does someone know?

I can answer your question of purging the keg, as we had a member who used to do that. Due to gas mixing, and "pockets" in the keg( the same pockets is why we can't properly purge kegs) it will result in a DO reading of about .2-4ppm in the finished beer, which will make your lovely lingering fresh malt go away in about 2-4 weeks.
Title: Volume of CO2 produced during fermentation?
Post by: Big Monk on January 12, 2017, 06:11:51 PM
(https://uploads.tapatalk-cdn.com/20170112/f501ce8a5f29f1fafc3862f842362a78.jpg)
Title: Re: Volume of CO2 produced during fermentation?
Post by: yso191 on January 12, 2017, 06:14:58 PM
Well, there you go.  Thanks guys!
Title: Re: Volume of CO2 produced during fermentation?
Post by: Big Monk on January 12, 2017, 06:17:12 PM
Well, there you go.  Thanks guys!

Like Sean said, temperature will factor into residual carbonation "lost" to the beer itself, but minimally.

Title: Re: Volume of CO2 produced during fermentation?
Post by: Stevie on January 12, 2017, 07:13:03 PM
Wouldn't there also be some undesirable compounds in there as well? I know many breweries capture and use their CO2, but they must be purifying it as well.
Title: Re: Volume of CO2 produced during fermentation?
Post by: The Beerery on January 12, 2017, 08:13:26 PM
Wouldn't there also be some undesirable compounds in there as well? I know many breweries capture and use their CO2, but they must be purifying it as well.

Probably, but they are liquefying it, then storing. Then turning it back into gas to use.
Title: Re: Volume of CO2 produced during fermentation?
Post by: Stevie on January 12, 2017, 08:41:57 PM
Wouldn't there also be some undesirable compounds in there as well? I know many breweries capture and use their CO2, but they must be purifying it as well.

Probably, but they are liquefying it, then storing. Then turning it back into gas to use.
That's what I was getting at. It may not be a viable solution for homebrewers without a large amount of equipment.
Title: Re: Volume of CO2 produced during fermentation?
Post by: The Beerery on January 12, 2017, 08:54:37 PM
Wouldn't there also be some undesirable compounds in there as well? I know many breweries capture and use their CO2, but they must be purifying it as well.

Probably, but they are liquefying it, then storing. Then turning it back into gas to use.
That's what I was getting at. It may not be a viable solution for homebrewers without a large amount of equipment.

Re-capturing or spunding?
Title: Re: Volume of CO2 produced during fermentation?
Post by: Stevie on January 12, 2017, 09:04:38 PM
Recapturing or purging. I don't have a pump that can get me 800+ psi.
Title: Re: Volume of CO2 produced during fermentation?
Post by: The Beerery on January 12, 2017, 09:17:13 PM
Recapturing or purging. I don't have a pump that can get me 800+ psi.
Oh yea! For sure!
Title: Volume of CO2 produced during fermentation?
Post by: Big Monk on January 13, 2017, 01:06:12 AM
Found this in DeClerck:

(https://uploads.tapatalk-cdn.com/20170113/71ea7adaaf1be3ecdf1bf3488c8c7a76.jpg)
Title: Re: Volume of CO2 produced during fermentation?
Post by: hopfenundmalz on January 13, 2017, 01:17:34 AM
Wouldn't there also be some undesirable compounds in there as well? I know many breweries capture and use their CO2, but they must be purifying it as well.
When I saw the unit at Sierra Nevada, it was stated that they remove aromatic impurities, and had a foul smelling jar of the stuff, concentrated esters and sulfur compounds. Alcohol that is gassed off also gets recovered, and was used to full on site vehicles, I.e. No road tax.

We all know the smells coming off of fermentaion, and CO2 is odorless. So yeah, it has to be purified.