BOSTON ( MainStreet) -- That smooth, creamy stout American beer drinkers are sipping this St. Patrick's Day may seem tame, but it's a nitro-powered brew that's driving brewers' creativity.
The not-so-secret ingredient that gives
its cascading bubbles and thick creamy head and gives craft breweries fizzy ideas of their own is nitrogen, and it's getting a lot more common. First used by Guinness in the late 1950s and early 1960s to maintain its beer's wooden cask character when the industry started switching to aluminum and fabricated metal kegs, nitrogen helped Guinness sales in the U.S. bubble up by 3.9% in 2010 and is sneaking its way into beer styles that bear little resemblance to Guinness' stout.
|The not-so-secret ingredient that gives Guinness its cascading bubbles and thick creamy head and gives craft breweries fizzy ideas of their own is nitrogen, and it's getting a lot more common.
"What we found as we started to develop pressurized systems was that you could start putting a little bit of nitrogen in and it would create this surge and settle process that became synonymous with the product," Guinness Master Brewer Fergal Murray says. "The use of the smaller nitrogen bubble which is inert and didn't change the flavor gave us the nice, more compact head on top of the pint that would last as long as the pint was in the glass."
It turns out nitrogen's effect translates just as well to red ales, lagers, cream ales and India Pale Ales. Joseph Tucker, executive director of beer ratings site
, compiled a list of the top "nitro" beers based on his site's ratings and had a pumpkin ale from Pennsylvania's
Selin's Grove Brewing
place third in a Top 10 dominated by stouts. Guinness came in at No. 11.
"Nitrogen is used in a variety of styles -- not just with dry stouts," Tucker says. "Some of the most successful nitro beers, in my opinion, are quite hoppy. A citrusy IPA or pale ale on nitro with the texture of an Orange Julius can be quite delicious."
So how does nitrogen work its magic? It all starts in the packaging process, when gas is added to beer to increase pressure and prevent it from feeling and tasting flat. In most cases, that gas is carbon dioxide, which keeps things nice and fizzy but has a tendency to make even light, low-alcohol beers feel heavy.