First hit of Nitro

I just got a nitrogen tank from Branntekknikk in Skien. They got me a filled pressure tested nitro tank for the same price as my CO2 tank, ca 1350kr. Unlike the CO2 tank, this one was a converted extinguisher.

I understood that beer gas is circa 30/70 percent CO2/N2, but what are these percentages, weight, volume, pressure? I didn’t know, and I had a hard time working out either of them. (PV=nRT….)

I’ve been told that that the mixed gasses behave inconsistently in the canister, so you start out getting more nitrogen, and then torwards the end, you get more CO2. (Anyone have experience of this?) The final blow for getting mixed gas was when I heard they charged quite a bit more for the work of filling the mixed gasses.

I went for straight N2, due to the uncertainties of getting mixed gas. This allows me to mix my gasses myself in the headspace of the keg. (I don’t have a kegerator yet, and just one regulator, so I disconnect the gas once the dispensing pressure has been reached.)

To mix the gasses, I use relative pressure. To serve at 12 psi, with a 25-75 mix CO2/N2, I’d fill first with CO2 to 3 psi, and then fill with nitrogen up to 12 psi. Initial results are pleasing, with reduced bitterness, thicker mouthfeel and a dense head. I need to try with a fresh batch, as these results are inconclusive due to the beer being already carbonated to 1.7 volumes of CO2 before adding the nitrogen, and at the current cellar temperature of 15C, that was 22 PSI.)

I also got a used restrictor faucet and Guinness handle on ebay for $20. It works a treat, but looks out of place, being stuck on the beer QD of the keg, but I don’t mind, it’s what comes out that’s important!