There’s no denying the romantic appeal of the cascading bubbles and tight foamy head of a properly poured nitro beer, but first the facts. Nitrogen is largely insoluble in beer (80–90 percent less so than carbon dioxide) at the temperatures and pressures we use to serve beer. Nitrogen is also flavorless, lacking the lemony acidic carbonic bite of carbon dioxide gas. And nitrogen’s use in beer gas is primarily to create higher pressure to force beer through a stout faucet. With that in mind, is there another way to accomplish the end result—that beautifully poured pint—without the nitrogen gas?
Before we explore how to capture that “nitro halo” in a glass, we need to look at the origin and function of nitrogen and the stout faucet.
Traditional hand-drawn cask ales always suffered from oxidation and short shelf life because air entered the cask to replace the beer as the beer was drawn. As carbon dioxide became more readily available, the problem was solved by replacing air with carbon dioxide gas. However, to serve from a keg that was 20 feet or farther away from the faucet, the pressure in the keg was such that carbonation levels rose significantly, from about 1.5 psi to 2.4 psi and higher. For some beer styles (stouts, in particular), the customers were less than overwhelmed by the resulting carbonation and taste.