Steam beer may be defined as a highly effervescent beer made by brewing lager yeasts at ale fermentation temperatures. It has two distinct but related meanings:
Historic steam beer, associated with San Francisco and the U. S. West Coast, was brewed with lager yeast without the use of refrigeration. It was an improvised process, originating out of necessity, perhaps as early as the Gold Rush. It was considered a cheap and low-quality beer, as shown by references to it in literature of the 1890s and 1900s.
Modern steam beer, properly known in the brewing community as California Common beer, was originated by Anchor Brewing Company, which trademarked the name Anchor Steam Beer in 1981. Although the modern company has corporate continuity with a small brewery which was still making traditional steam beer in the 1950s, Anchor Steam beer is a craft-brewed lager. The company does not claim any close similarity between it and turn-of-the-century steam beer.
Explanations of the word "steam" are all speculative. The carbon dioxide pressure produced by the process was very high, and one possibility is that it was necessary to let off "steam" before attempting to dispense the beer. According to Anchor Brewing, the name "steam" came from the fact that the brewery had no way to effectively chill the boiling wort using traditional means. So they pumped the hot wort up to large, shallow, open-top bins on the roof of the brewery so that it would be rapidly chilled by the cool air blowing in off the Pacific Ocean. Thus while brewing, the brewery had a distinct cloud of steam around the roof let off by the wort as it cooled, hence the name. It is also possible that the name derives from "Dampfbier" (literally "steam beer"), a traditional German ale that was also fermented at unusually high temperatures and that may have been known to nineteenth-century American brewers, many of whom were of German descent.
Final flavors of beer are influenced by the strain of yeast and the fermentation temperature. Lager yeast is best used at temperatures from 55°F down to 32 °F. Classic lagering of beers takes place over a period of time from weeks to many months at a temperature of 45°F. Lager yeasts are bottom fermenting, which is to say that they ferment the wort while sitting on the bottom of the fermenter. Papazian, Charlie (2003). The Complete Joy of Home Brewing: 3rd Edition.
Ale yeast is best used at temperatures from 55°F to 75°F. Fermentation by ale yeasts produces a beer that has a distinctive ale flavor. Ale yeasts are Top-fermenting, that is they settle out on top of the wort after fermenting (fermentation itself takes place in a suspension. Papazian, Charlie (2003). The Complete Joy of Home Brewing: 3rd Edition. Steam Beer uses bottom fermenting lager yeasts at ale temperatures, which results in a very distinctive flavor profile that includes both ale and lager characteristics.
While steam beer is considered a specialty microbrew style of beer today, it was originally a cheap beer made for blue collar workers. Wahl & Heinus’ “American Handy Book of Brewing and Malting” (1902) describes California Steam Beer as “a very clear, refreshing drink, much consumed by the laboring classes.” And while Anchor Steam is an all-barley malt beer, additives were often used in the early days. According to Wahl & Heinus’ book, “Malt alone, malt and grits, or raw cereals of any kind, and sugars, especially glucose, employed in the kettle to the extent of 33 1/3 percent…. Roasted malt or sugar coloring is used to give the favorite amber color of Munich beer.”
As a budding writer, "a wild band of young revolutionists invited me as the guest of honour to a beer bust" and was challenged to a drinking contest.
When he marries, his wife convinces him to adopt more refined habits:
According to the Beer Judge Certification Program, the term California Common beer, designated style 7B, is "narrowly defined around the prototypical Anchor Steam example", and other commercial examples include Southampton West Coast Steam Beer, Old Dominion Victory Amber, and Flying Dog Old Scratch Amber Lager. The style "showcases the signature Northern Brewer hops (with woody, rustic or minty qualities) in moderate to high strength", is fermented with "a lager yeast, but one that was selected to thrive at the cool end of normal ale fermentation temperatures", and was traditionally fermented in large, shallow, open fermenters called coolships.
A British brewery, the Lincolnshire Steam Beer Co., derives its name from the steam-powered brewing machinery.
Canadian brewers Sleeman also have a Steam Beer available. They were once sued by Anchor over the term "Steam beer", but the Canadian courts allowed Sleeman to continue using the term as Anchor had not been available on the Canadian market prior to the Sleeman product.