Mixed gas is it ok?

[headcase.brewing]

I am about to keg an imperial stout. I have a bottle of mixed gas that I used for a Guinness awhile back. It is 65% nitrogen and 35% Co2. Will this work with an imperial stout? or should I use straight Co2.

[Stewbacca]

im not certain but i would assume that if you are using a stout faucet with the mix it should be fine.

then again i dont even have a stout faucet so what do i know.

[ajdelange]

Mixed gas is fine for any application where you want high pressure to push the beer hard but not the high level of carbonation which would arise from pushing that hard with CO2. Thus where the beer is to be forced through a sparkle plate in a stout faucet but low carbonation is wanted (Guiness ~ 1.2 volumes) is the typical application for a 20/80 mix whereas long serving lines would typically use 60/40. For a 35/65 mix you will need about 18psig at 38F to acheive 1.2 volumes. Whether this is enough for an Imperial I couldn't say as the whole idea behind the nitrogen mix is the creamy head from the sparkle plate it seems a moot question if a stout faucet is not being employed. For higher carbonation you will clearly need more pressure which means the beer will come rushing out of the keg unless a choker line is installed or the keg is held at the higher pressure to establish the desired carbonation level and then bled to a lower pressure for serving (and then restored to the higher pressure until the next session).

[dresselbrew]

I am about to keg an imperial stout. I have a bottle of mixed gas that I used for a Guinness awhile back. It is 65% nitrogen and 35% Co2. Will this work with an imperial stout? or should I use straight Co2.

It depends. How's that for an answer.

ajdelange pretty much sums it up. I think the nitrogen might help with the creamy head but you can get a good head with straight co2. A normal faucet will work with beer gas too if you balance it right. Like add some sort of restrictor before it to bring the pressure at the tip to 0psi. The restrictor can be a bunch of beer line or some sort of flow gate. http://www.maltosefalcons.com/tech/resistive-gate-draft-beer-flow-control I just shoved the mixer in my beer line instead of making one of these but you get the point.

Just remember the the carbonation level is proportional to the mix %. 10 psi of 100% co2 is the same as 28.5 psi of a 35/65 mix assuming the same temperature. 10/0.35=28.571.....

[ajdelange]

[quote="dresselbrew"
Just remember the the carbonation level is proportional to the mix %. 10 psi of 100% co2 is the same as 28.5 psi of a 35/65 mix assuming the same temperature. 10/0.35=28.571.....[/quote]

True, but you have to use psia in partial pressure calculations. 10 psig 100% CO2 is 25.7 psia. To get 25.7 psia partial pressure of CO2 from a 35% mix you need 25.7/.35 = 73.4 psia which is 58.7 psig.

[headcase.brewing]

Thanks for the tips. I have a Guinness facet with the restrictor plate that I have used before. I just finished listening to the carbonation podcast on BREW STRONG. The ABV on this beer is about 7.5% and a FG of 1.020 from what they were saying on BREW STRONG Nitrogen is not the same as CO2 when it comes to mouth feel and aroma. Not sure which way to go on this one. I would try out the beer mix first since I have had the bottle for awhile and want to use it up. From what I have gathered I could try out the beer mix at 15 psig then ramp it up slowly.

If I didn't like it though, could I go back to straight CO2? I think if you slowly reduce the pressure and let out the nitrogen since it is not as readily dissoluble as CO2 then keep the pressure on the CO2 . Or maybe thats the beer talking.

http://www.micromatic.com/forum/us-en/t ... stout.html

I found this thread on micromatic the consensus seems to say to just use 100% CO2. However as a home-brewer I am always thinking what would that taste like.

[ajdelange]

It might be wortwhile to remind ourselves that the whole nitrogen thing got started as a way to try to replicate the creamy head produced by a hand pump and sparkler without the handpump (or sparkler) on beers that were traditionally served from engines. The dry Irish stouts are definitely in this class but the Imperials are not (AFAIK) being put up strong in bottles for shipment to the Russian court. Thus the creamy head and associated essentially flat beer associated with nitrogen and/or beer engines might be totally inappropriate for imperial stout. Of course if you like it that way, that's what counts so you could definitely try the stout faucuet with mixed gas and if you don't like it go to straight CO2. As the nitrogen really doesn't dissolve in the beer to any appreciable extent once you bleed off the gas in the keg (assuming it is blend at 18 psig) you will have in essence a beer carbonated to 1.2 volumes of CO2. Just put on CO2 at whatever pressure you select to give the volumes you want and let it re-equilibrate.

Another factor to consider in the use of the stout faucet is that imperial stout is most likely appreciably more viscous than dry stout so you may get a very slow pour even at 18 psig blend.

[headcase.brewing]

Well it is in the keg and rolled it at 20PSI for 5 min and let it sit. 10 min later rolled for another few minutes. Will let it sit a few more minutes and then one last shake.

I checked the tapper and it flow fairly fast with the standard tap. I will wait until tomorrow to see how it works. I may go with a Guinness tap for the party.