Co2 and gravity kegging

[fernando71]

Hi

I have Speidel type fermenters (120L) and they rest at a platform about 1.5m above the floor. When I transfer I do it using the gravity into the keg and it works great. We have an internal discussion about to use or not use Co2 into the fermenter while kegging to avoid oxidation from air entering the fermenter over the transfer process.

My justification is that Co2 is heavier than air thus the Co2 will always be in the layer between the beer and air and would not risk oxidation.

Any thoughts? arguments as why I should use Co2?

 

[Broken Crow]

Do you connect a gas line from your keg to the Speidel? If so, you're only exchanging the volume of one for the volume of the other. The only reason to connect CO2 is to push it through without O2 contamination, and then use the PRV or (better) a spunding valve to vent the keg while doing your best to maintain a back-pressure and keeping foaming minimal. The mythical "CO2 Blanket" is easily disturbed the moment you introduce a stream of air and it mixes.. CO2 is not always in a layer owing to gravity when there is turbulence and freely mixes and then takes a relatively long time to settle out again...days, not the minutes it takes to displace and fill a keg. If you've pushed CO2 and krausen to the top of your Speidel and pushed all the O2 out in fermenting, then reasonably, you should only have CO2 in it and be fine with using a sanitized and purged gas-return line from the keg back up to the FV.

 

[mac_1103]

My justification is that Co2 is heavier than air thus the Co2 will always be in the layer between the beer and air and would not risk oxidation.

The myth of the CO2 blanket dies hard. For the most part, gases tend to mix much more readily than they tend to stratify. Like Broken Crow said, the best approach is to set up a closed loop between the FV and a purged keg.

 

[doug293cz]

The CO2 "blanket" is a myth. CO2 and air will mix completely in a matter of minutes (all gases behave this way._Check the video. CO2 and NO2 (later in the video) are similar weight, and mix very fast with air.

GCSE Science Revision - Diffusion of Gases - YouTube

Brew on

 

[fernando71]

Thanks a lot for the replies. That said...Co2 will be used while transfering. The idea of conecting the keg output to the top of the fermenter sounds like a good solution to stop air entering the sistem.

 

[fernando71]

The CO2 "blanket" is a myth. CO2 and air will mix completely in a matter of minutes (all gases behave this way._Check the video. CO2 and NO2 (later in the video) are similar weight, and mix very fast with air.

GCSE Science Revision - Diffusion of Gases - YouTube

Brew on

Very interesting and ilustrative video. Thanks