Originally Posted by 732Brewer
My local shop sells:
Nitrogen 75 / 25 CO2
Nitrogen 60 / 40 CO2
I was under the assumption that I would get pure co2 but it seems that from doing reading, I want a blend. Guys please comment on what you get when you fill up. Thanks!
Depends on your serving temp and carb level, but most people are better off with a higher CO2 content blend. Most nitro faucets work best at 30-35 psi, and you want the equilibrium pressure of the carb level and temperature to be close to your serving pressure. You'll want to keep the carb levels fairly low either way, since nitro faucets usually make a foamy mess if the beer is carbed over ~1.8 vol. The 75/25 blend is also known as G-mix, which stands for Guiness. That's because it's used to serve Guiness, which is carbed at 1.2 vol, and stored under commercial conditions of 35-36°. Most people prefer either slightly higher carb levels, or slightly warmer temps, either of which will work better with a higher CO2 level blend.
Here's a handy calculator for gas blends-http://mcdantim.mobi/easypsig.html