Originally Posted by syvmn
I am a few days away from getting the rest of the parts I need to finish up my nitro tap and I have a few questions.
I have a freshly brewed guinness clone that is also a few days away from going into a keg. From what I can gather, I should carbonate it on pure CO2 up to about 1.5-2.0 volumes then push it with my beer gas at around 25-30psi. I want to serve it around 45F so that gives me a CO2 carbing range of about 3-8psi.
Does anyone have suggestions for the initial carb level of a Guinness Clone?
Also, when I put it on beergas @ 30psi how will that affect my carb level. I don't know the specific makeup of my beer gas, its either 75/25 or 70/30. This may be over simplified math, but since it is 25-30% CO2, does that effectively make the carbonation level 25-30% of 30psi? That would equal roughly 7.5-9psi of pure CO2.
Hopefully my questions made a bit of sense. I feel like I'm just rambling.
Thanks for any help.
Guinness is carbed to 1.2 vol. I suggest keeping the carb level at or under 1.8 vol, especially since you're using a higher serving temp. At that temp you may have problems with foaming if you carb it much over 1.2 vol. Keep in mind that pouring the beer raises the temp a few degrees, so if you want to drink 45° beer, you should store it and serve it at ~42°.
The math for beer gas is more complicated than what you have posted above. Rather than try to explain it in a way that makes sense, I'll just give you a link to a carbonation calculator that works for blended gasses.