Nitro-glycerin. Adds a certain "bang" to it. Don't shake the bottles.


Actually, Nitrogen (N) is mixed with some Carbon Dioxide (CO2) (usually around 70/30), known as beer gas in the industry. Nitrogen makes microbubbles that are not soluable in beer, hence the thick creamy head. It's served using a special Nitrogen tap with a sparkler at the tip to strip the Nitrogen away, creating that cool looking cascading foam in the glass, a la Guinness.

Another blend of it is used to push beer long distances in pubs. When using straight CO2, the high pressure required to push beer, say 60 feet, not only may dissolve in the beer--thus changing the intended carbonation level--but also creates excessive foaming; wasting beer. So by using beer gas, pubs can save a lot of money.