Inject CO2 for 2nd fer headspace

[peresian]

Hi !
If 2nd fer jar is too big , then may I fill head space by CO2 ? My jar is 20L but the liquid must be about 14L (after rack)
If answer is yes , would u show some methods for co2 injection ? May use airstone ?
As the empty space is about 6L , how much co2 must be use ? my CO2 cap is about 4kg .
Thanks

 

[aspiffymofo]

It's better not to rack if you don't need to. Every time you transfer there is a chance for oxidation. But if you are going to do it just purge the secondary with CO2 for a few seconds and then rack into that carboy.
But if you can leave it in the primary until it's time to keg or bottle, your beer will thank you for it.

I hope I'm answering your question.

24.46L/mol of gas at 25C. CO2= 12+(2)16= 44g/mol
22.46L=44g. > 6L = 11.7g of CO2
This assumes a perfect replacement, with no mixing. However it illustrates that you don't need much.

 

[Maylar]

CO2 is heavier than air. Just blow some into the headspace for a few seconds and it should displace the oxygen. I use vinyl tubing from the regulator with just a couple psi of flow.