by Peter A. Ensminger
Republished from BrewingTechniques' May/August 1997.

It sometimes happens that history and fortune intersect at precisely the right time and place. Pilsner Urquell emerged from a small Bohemian village in the 19th century to become what is now the world's most imitated original.

The first Pilsener, brewed in 1842 Bohemia, was a lager unlike any other. Its brilliant clarity, golden color, and light body made it an instant success in a world that was accustomed only to dark, heavy, cloudy beers. Its popularity soared. Within a couple of decades it was being exported around the world.

No sooner had shipments of this new beer reached American shores than brewers set to work duplicating the style. The import's subsequent impact on American brewing trends is most manifest in the popularity of its most famous American successor, Budweiser. No imitator, however, can hope to match the true character of this Czech original. Brewed with a combination of soft Plzen water, home-malted barley, superb native Saaz hops, and a lager yeast originally smuggled out of Bavaria more than 150 years ago, Pilsner Urquell is to this day a true king of beers.

The Kingdom of Beers -- A Brewers' History of Bohemia
The origins of Pilsener beer can be traced back to its namesake, the ancient city of Plzen, located in the western half of the Czech Republic in what was formerly Czechoslovakia and, before that, part of the kingdom of Bohemia. Brewing in this region dates back hundreds, if not thousands, of years. Though surely incomplete, early historical records show that the Slavs, the ethnic and linguistic group to which Czechs belong, served beer to Byzantine envoys as early as A.D. 448 (1,2). Additional sources indicate that Bohemians were growing hops by the year 859 (3) and brewing beer by 1088 (4).

Then-brewer Jaroslav Rous (left) and beer writer Darryl Richman talk in the railyard in front of the brewery during Richman's 1990 tour.

Plzen's contribution to beer history began in 1295, when the King of Bohemia, Wenceslas II, founded the town of New Plzen on the banks of the Radbuza River (1). Old Plzen was located nearby, about 9 kilometers southeast in the Uslava Valley, in an area that was not easily accessible for trade. King Wenceslas chose the new site carefully, placing New Plzen (now known simply as Plzen) near the confluence of four waterways, the Mze, Radbuza, Uhlava, and Uslava Rivers. The city was also near the junction of major trading routes leading to Nuremberg, Regensburg, and Saxony (1,5). It was a site that would put the city at center stage in an exciting chapter in brewing history.

At the city's founding, King Wenceslas gave its 260 citizens the right to make beer and sell it from their houses, a lucrative privilege that was passed down through each family. The first written records of a distinct brewery in Plzen date back to 1307 (1,4,5). Evidence suggests that many of the early residents of Plzen formed joint breweries and even a community malthouse to make production more efficient, with individual brewers making their own wort and then dumping it into a large vat for fermentation (2,4).

Pilsner Urquell's malthouse, located on the property. The brewery performs all of its own malting here with barley brought in from Bohemia and Moravia.

Brewing guilds: The consumption of beer became more and more prevalent. Brewing began to evolve as an important part of the social, economic, and political fabric of the region, bringing high profits and more attention to process -- and even to politics.

As was the trend with other European trades, the brewers and maltsters of Plzen eventually formed guilds primarily for economic reasons but also to help ensure that the accumulated knowledge of their trades would be passed down through the generations. Plzen's brewing and malting guilds soon united, choosing as an insignia two crossed wooden brewing tools: a specialized shovel used for turning malt and a ladle used for mixing yeast (2,4). Even today, many breweries throughout the world display variants of this famous insignia to honor the ancient crafts of malting and brewing.

The guild honored King Wenceslas II as its patron saint, as well as the memory of King Gambrinus (whose name is probably a corruption of Jan Primus, or Jan the First), the legendary first brewer of beer and an ongoing symbol of beer and brewing.

Early publications on beer and brewing: The early 1500s ushered in a growing appreciation for quality beer, as evidenced in part by the establishment of the Reinheitsgebot (beer purity law) in Bavaria during this time. The

Microbiological incubators. Yeast slurries await their turn in special vats. Pilsner Urquell's current yeast strain may well date back to the mid-1800s.

Czechs, however, took the lead in the published promotion of beer appreciation, though not everything that was published was serious.

Jan Franta, a Czech doctor and noted beer connoisseur, developed a light-hearted code of conduct for a guild of beer drinkers -- who duly called themselves Frantas. In 1518, only 60 years after Johann Gutenberg first used movable type to print The Bible, Franta published a whimsical book called Franta's Rights (4), written in the Czech language and printed in nearby Nuremberg. The world's first book about brewing -- a Latin text called On Beer and the Methods of Its Preparation, Its Substance, Strengths, and Effects -- was printed in 1588 by another Bohemian named Tadeas Hajeck (4).

Brewing history takes a setback: Bohemia's zymurgic golden age was not allowed to flourish uninterrupted, however. Conflicts between Czech Protestants and Hapsburg Catholics came to a head on 23 May 1618, when an assembly of Protestant Czechs, long persecuted by the Catholic Hapsburgs, threw the Hapsburg governors of Bohemia out the windows of the Prague Castle. Legend holds that the victims survived their fall by fortuitously landing on a pile of dung, but historians generally agree that the "Defenestration of Prague," as the event is known, was what precipitated the Thirty Years War (1618-1648).* During the ensuing struggle, rampaging mercenaries destroyed cities throughout Bohemia, Bavaria, and much of Europe, spreading the plague as they traveled (6). The depredation of this era delivered a serious blow to brewing progress. By the time the treaty of Westphalia brought the Thirty Years War to an end, the power of the Holy Roman Empire had been critically eroded and much of Europe was in ruins (6), as was its beer.

Technical advances: Eventually, Czechs such as Frantisek Ondrej Poupe (1753-1805) reintroduced scientific exploration in the pursuit of brewing progress. Czechs claim that Poupe was the first brewer to use a thermometer (4), invented about 200 years earlier for the purpose of measuring human body temperature (7). By the 1800s, brewing was becoming even more technical and specialized, and formal training programs began to emerge. The renowned Professor Karl Balling, for example, developer of the Balling scale (a measure of the sugar content in a solution) was appointed lecturer on the chemistry of fermentation at Prague Polytechnic. Prague was also the home of a brewing school (founded in 1869, four years after Weihenstephan in Germany) and a malting school (founded in 1897) (2,4).

A passage through time. Beer was formerly lagered for three months in these 25-hL casks lining the sandstone cellars beneath the brewery. The casks have been replaced by 3,300-hL stainless steel vessels. Photo courtesy of the brewery.

Understanding yeast: The early 1800s brought many important developments to the understanding of yeast microbiology. Brewers of the period knew that yeast was needed for fermentation, but they were uncertain of its precise role and had no way to propagate it intentionally. German scientist Theodor Schwann's experiments (1837-1838) demonstrated that yeast cells grew and reproduced during fermentation; he argued that fermentation was a living process. The renowned German scientist Justus von Liebig, on the other hand, maintained that fermentation was a chemical reaction triggered by the death and decomposition of yeast cells (8). Pasteur's later work showed that Schwann was right -- it is the living yeast cells that convert sugars into ethanol. These experiments provided a key backdrop for the events to come.

Beer quality had been deteriorating during this period, probably due to a lack of understanding about proper fermentation practices (9,10). Bohemian brewers, armed with their new-found knowledge of yeast, began to connect differences in style with variations in yeast properties. In 1838, several of the city's brewers deemed 36 barrels of local beer undrinkable and dumped it out in the town square, right in front of City Hall (4,10,11). The brewers decided that building a brewery would serve the dual purpose of making money and brewing better beer.

Legend has it that soon after this event (1840), a strain of much-envied bottom-fermenting yeast was smuggled out of Bavaria by a monk (12) and passed on to a Bohemian brewer (13). The resulting beer met with instant success, and two years later, the brewery responsible for launching the Pilsener style began operations.

The Birth of a Brewery and New Brewing Tradition
Pilsner Urquell's brewery began as a collective facility operated by several of Plzen's independent brewers, who designed it specifically to brew the new lager style. The brewery was built on the bank of the Radbuza River, near a well and directly above a sandstone foundation that was easily carved with tunnels for cold storage, or lagering, of this new breed of beer. A 29-year-old lager brewer from Bavaria, Josef Groll, was named master brewer of the new enterprise (2-4). Originally known as the Mestansky Pivovar (Citizens' Brewery), the brewery was later renamed Plzensky Prazdroj, meaning "original source of Pilsener" in Czech.

The Plzen brewery first sold Josef Groll's clear, light-colored lager in 1842. The beer acquired the name Pilsner Urquell (urquell is German for "original source"), in honor of the language of the ruling Austrian Empire (14). Though certainly distinctive, Pilsner Urquell was far from the first beer to be lagered. Bavarians had been brewing lagers at least as far back as the 1400s, when their method of storing beer in the cool caves of the Bavarian mountains inadvertently selected for lager yeast, which thrived at the low temperatures. These Bavarian lagers were mostly dark beers, however, and any light-colored ales that were available were probably cloudy (3).

The timing was right for Pilsner Urquell to sell the lager that was to become the model for so many others. The lagering process so recently arrived to Plzen produced a smoother and mellower beer than any Bohemia's brewers had created before; clearly, the cooperative effort resulted in a dramatic turn-around for Plzen's beer quality. New and improved kilning methods also contributed

How Do the Imitators Stack up to the Original?
Specifications	Pilsner Urquell	Dortmunder*	Budwiser
O.G. F.G. Alcohol (v/v) Color (°L) IBUs	1.048 (12 °P) 1.015 (3.8 P) 4.4% 4.2 40	1.048-56 (12-14 °P) 1.010-14 (2.5-35 °P) 5-6% 3-5 23-29	1.045 (11.25 °P) 1.009 (1.5 °P) 5% 2.2 12
*GABF style guidelines, 1996 (24). Traditional Dortmunder lager had an O.G. of 1.061 (15 P), 5.6% alcohol by volume, and a bitterness of 32-37 IBUs. That beer was slightly darker than the Czech Pilsner of that era (13).

to the success of Pilsner Urquell by enabling maltsters of the period to produce a pale malt that lent an unusually light wort. As if to cinch the beer's popularity, its clear, golden appearance looked especially handsome in the well-known Bohemian crystal that was just becoming popular in Europe and the United States (13).

Word of Pilsner Urquell quickly raced through Europe, and before long (1859) the brewery made "Pilsener Beer" a registered trademark (2,15). The beer was finally exported to America in 1871 (12). In 1898, following numerous breaches of the Pilsener trademark by imitators, the brewery took further precautions by also trademarking the name "Pilsner Urquell" (2,15). Interestingly, Anheuser-Busch applied for trademark of the Budweiser name in 1907, even though Czechs had long known of "Budweiser" as the beer from the Czech city of Czeske Budejovice, or "Budweiss" in German (3,16). Anheuser-Busch's "Michelob" brand is also named for a Czech town, Michelovice. (Anheuser-Busch's right to sell beers in Europe and Asia under the Budweiser trademark is being hotly disputed in the courts.)

Over 150 Years of Control and Production
Technological advances in energy and transportation enabled Pilsner Urquell to grow quickly in the late 19th century. Steam was starting to be used in European breweries, and refrigeration techniques allowed beer to be lagered year-round (9). The brewery first used gas for lighting in 1865, and was wired for electricity in 1891. Exports increased with the opening in 1962 of the West Bohemian Railway; by 1865, three-fourths of the brewery's beer was being exported, and it was #3 in Czechoslovakia in production.

By 1913, the brewery was producing more than 1 million hL of Pilsner Urquell per year and was the largest brewery in Europe. Since that time, however, output has fluctuated under the pressure of two world wars and 40 years of Soviet domination -- the brewery was nationalized in 1945 -- but its yearly production in 1996 was back up to nearly 1 million hL (15). Production is expected to increase to 1.1 to 1.15 million hL in 1997.

Pilsner Urquell has been a publicly owned company since the demise of Communism in 1989. The largest shareholder (51%) is a Czech bank, Investicni a Postovni Banka a.s. Another 10% of the shares are still held by the Licensed Brewers Association, a group comprising the descendants of the original shareholders before nationalization. Over the years, Pilsner Urquell bought out a number of other Bohemian breweries, including the adjacent Gambrinus Brewery (founded in 1868 as First Shareholders Brewery) and breweries in Cheb, Karlovy Vary, and Domazlice. The brewery in Domazlice closed early in 1997 for economic reasons; Gambrinus is now producing Domazlice's Purkmister black beers under the Gambrinus label, along with six other beers. Taken together, the current annual output of the four breweries was 4.05 million hL in 1996 and is expected to rise to 4.5 million hL in 1997. Nearly 90% of that output will come from the city of Plzen alone. Pilsner Urquell also reportedly owns a 51% interest in a brewery in Lithuania (17).

History preserved amid modernization: The brewery has taken many steps toward modernization in the 20th century while trying to maintain the quality and character that made its beer such a success. Part of the transformation involved a gradual phase-out of the brewery's long-standing brewing methods in favor of expanded capacity and modernized facilities. The years following Vaclav Havel's Velvet Revolution have yielded the most drastic changes as the brewery has taken steps to compete in the country's newly adopted capitalist economy.

The most prominent and widely reported change came in 1992, when the brewery replaced its traditional oak fermentors with shiny new stainless steel vessels -- a move first contemplated as far back as 1929. Although the brewery conducted extensive taste comparisons and claims to have preserved the original character and flavor of the beer, Pilsener aficionados still debate the topic.

Inside the Brewery -- The Making of an Original
Soft water: As is true with many of the world's best beers, the water used in Pilsner Urquell is distinctive. In this case, it is very soft, containing only about 50 ppm of total dissolved solids; Burton water, by contrast, contains about 1,200 ppm. The water also contains only about 10 ppm calcium, meaning that the brewers must adjust the pH during the mash. Other major ions in the water include sulfates, chlorides, and hydrocarbonates (18). Water used to make Pilseners and other lagers in the German city of Dortmund contains about 1,000 ppm of total dissolved solids with much higher calcium and sulfate levels (3). Dortmund is better known for its Dortmunder Export lager, a classic beer style that typically has more body and strength but less hop bitterness and aroma than a Pilsener. The Dortmunder Actien Braueri does make a nice Pils (German-style Pilsener), although the Dortmund water lends it a longer-lasting bitterness compared with that of the lagers produced by Pilsner Urquell.

The old coolships at Pilsner Urquell. The pipes in the background used to deliver wort to these large open vats, where trub could settle out and cooling was accomplished by huge fans. Modern heat exchangers now do the work.

The brewery draws its large supply of water both from municipal water supplies and from its own special Artesian wells located about 3.5 kilometers from the brewery. The well water is preferred for malting in part because it has a more constant temperature than the city water (18). It is treated to remove iron and manganese and is stored on-site in the prominent historic water tower located between the Pilsner Urquell and Gambrinus breweries (see cover for a glimpse).

Proprietary malt: Pilsner Urquell obtains barley from both corporate and private crops in Bohemia and nearby Moravia and now malts its own grain (about 64,000 tons per year) in malthouses on the grounds of the Pilsner Urquell and Gambrinus breweries. The barley is germinated for only about five days to about 60-75% modification (15,19). Pilsener malt has a color of about 2.0 °L, lighter than most English pale ale malts, but on a par with most of the two-row or six-row malts used by many American megabreweries. The Pilsener malt also has a relatively low protein content (less than 11%), which contributes to the beer's clarity.

Triple-decoction mashing: Pilsner Urquell's mash is performed in 200-hL (170-bbl) vessels and follows the same triple-decoction method used for the past 75 years (18). Thick portions of the mash are drawn off at three different times over the course of more than four hours. Each portion, or decoction, is heated to saccharification temperature, then boiled briefly, and finally returned to the main mash vessel to step up the main mash's temperature. The mash begins with cold water stirred into the grains; hot water is added to bring the temperature to 95 °F (35 °C) for an acid rest. (According to the brewery's quality control manager, Pavel Prucha, the water-to-grain ratio is 1.85 L to 1 kg.) The first decoction raises the temperature to around 127 °F (53 °C) to break down the larger proteins; the second addition raises the mash temperature to 143 °F (62 °C) for starch conversion; and the third brings the temperature to about 163 °F (73 °C) for mash-out (18).

Boiling the mash during decoction breaks down the protein matrix that surrounds the starch, making it more accessible to starch-degrading enzymes in the malt (20), which may offset the fact that the malt is not fully modified. The multistage decoction also helps to adjust the mash pH in a way the water's natural ions cannot (9). The resulting Bohemian Pilseners are a little bit darker (Pilsner Urquell is about 4 °L) and have a slightly stronger and more complex hop character than their German Pils counterparts, which are generally brewed using a double decoction mash schedule (9,20). The Urquell that is exported has a starting gravity of 12 °P (1.048 S.G.).

Saaz hops: Pilsner Urquell boils the wort for two hours and uses three additions of whole Saaz hops at a rate of 350 g/hL to bring the IBU level to 40 (18). The hops are grown in the nearby Zatec region of Bohemia. Hops are initially added into the sweet wort before it reaches a boil (first wort hopping); more hops are added about 80 minutes before the end of the boil, and the final addition is added about 25 minutes before the end of the boil. (Pilsner Urquell is not dry-hopped.) Alpha-acid levels in the Saaz hops during the past five years have averaged about 3.8% (18).

A portion of the brewery's primary fermentation formerly took place in these open steel fermentors.

Fermentation: The boiled wort is then cooled and aerated. Rooms full of coolships have been replaced by more modern heat exchangers (21). The classical fermentation procedure, which originally involved five different yeast strains in separate open wooden (and later, both wood and steel) barrels, was changed in 1993. According to Prucha, Pilsner Urquell now uses only one strain of yeast, called the H-strain, which may well date back to the original brewery (the nearby Gambrinus brewery uses Weihenstephan yeast that is so commonly found in these styles). Primary fermentation takes place in 40 closed stainless steel cylindroconical fermentors, each of which holds 1,800 hL of beer (1,530 bbl) (18). The brewers pitch about 0.5 L of a thick yeast suspension per hectoliter of hopped wort, which translates to about 15 million yeast cells/mL. The yeast is pitched at 39 °F (4 °C), and primary fermentation lasts 11 days. The temperature is allowed to rise to a maximum of 48 °F (9 °C) before fermentation is halted and the young beer from each of the fermentors is combined for lagering (18).

Rous in the brewery's foggy underground lagering caves. A brine refrigerant kept the caves cold. The ground is laid with tracks for hand trucks that lead to a manual keg filling machine visible in the background.

The lagering phase: In the past, Pilsner Urquell was lagered for three months in 25-hL wooden barrels stored in a network of sandstone tunnels beneath the brewery. The tunnels extended for about 6 miles and occupied an area of 2,250 square miles (about half an acre). The oak and beechwood barrels were lined with pitch, a dark resin extracted from conifer trees (3,15), to protect the beer from any contaminants in the wood. The modern practice adds the blended beer to 56 stainless steel tanks, each holding 3,300 hL, for 35-40 days of lagering (18).

Packaging: The beer is filtered with a modern diatomaceous earth candle filter. The brewery also recently added a new Simonazzi bottling line and Krones labeler with a capacity of 42,000 bottles/hour, and is planning for another. The other, older lines have been gradually updated over the years to improve the filling and labeling process (18).

Profile of a Classic Beer
The final product has a bitterness level of about 40 IBUs and a nicely balanced aroma of Saaz and malt. Despite the relatively high IBUs, Pilsner Urquell impresses most beer aficionados as having a very soft and malty taste, no doubt the result of soft water and triple-decoction mashing, both of which emphasize malt character in finished beers. The original gravity of the export is about 12 °P (1.048 S.G.), with a final gravity of 3.8 °P (1.015 S.G.), and an alcohol content of 4.4% (v/v) (18). The brewery also produces 10 °P (1.040 S.G.) beer to appeal to the increasingly lighter Czech tastes (17,19).

Pilsner Urquell's flavor profile includes some diacetyl notes, detectable to some beer drinkers as a buttery flavor. The brewery claims the maximum allowable level is 0.12 ppm, a bit on the high side, but probably due to the beer's incomplete fermentation. Few, however, seem to find the flavor objectionable (9). Some would even say that it enhances the beer by giving it added complexity.

One thing that hasn't changed, and isn't likely to, is the beer's hallmark green bottles. The company's steadfast commitment to maintaining traditional methods as much as possible unfortunately includes a bottle color that makes Urquell more susceptible to skunky "lightstruck" reactions if the bottles are exposed to sunlight during distribution (22). It's also not uncommon to drink an export that is oxidized, or stale. One possible reason might be the brewery's pasteurization regime. All beer, whether in bottles or kegs, is tunnel-pasteurized; the brewery maintains that domestic beer will stay fresh for six months, and exported beer for one year. The lengthy process that is necessary to maintain microbial purity may be a source of potential oxidation and may also destroy some of the subtleties of the hop aroma (9). To obtain a wholly uncompromised sampling of Pilsner Urquell, you may have to venture to Plzen itself.

Forecast -- Continuing Reign
It is probably reasonable to expect a few changes after 150 years of brewing, if only to keep up with an increasingly competitive industry, but the brewery fights hard to maintain its traditional character, despite the cries of compromised quality from many Pilsener aficionados. The recent changes in fermentation and lagering practices raised enough concerns at the brewery to warrant a full-scale taste test analysis. The group of independent experts who were asked to evaluate the new beer were unable to tell the difference between the taste of beer made using the new stainless steel system and beer lagered in the older wooden barrels (15), though Michael Jackson, for one, does report that he can detect a difference (23).

The brewery's oak legacy lives on, however, in the architecture of the 560-seat restaurant/pub, Na Spilce -- the largest in the Czech Republic (15) -- which now sits in place of a portion of the traditional sandstone lagering cellars beneath the brewery. Much of the woodwork in the restaurant is carved from the brewery's old stock of wooden barrels (18). In addition, a "working museum" in the original old sandstone cellars is nearly complete, featuring the wooden vats and barrels originally used for primary fermentation and lagering, now newly reconditioned and fully operable. Visitors may tour the traditional setup and compare for themselves the old and the new Pilsner Urquell.

For those wanting to put the old and new to the test themselves, the trip will yield more than just a taste comparison. The surrounding city is a living record of the progress of brewing. A brewing museum located near the town center on the riverbank opposite the brewery houses more than 18,000 exhibits and showcases many beautiful brewing artifacts that document the history of brewing in Plzen. The museum was founded in 1959 and was modernized in 1991-1992. (The house that holds the museum is an architectural time capsule in its own right; the building was used for malting barley in the Middle Ages and was converted into a pub in the 1800s [1,4,19].)

Whether you see the transformations at Pilsner Urquell as an unwelcome compromise with tradition, as an evolutionary change, or as a skillful and successful updating of technology to preserve the past, no one will dispute that its beer presents a quality and character all its own. Pilsner Urquell will surely move forward with its own chapter in the history of brewing.

Acknowledgments
I am grateful to Jaroslav Rous (vice president of sales and marketing, Pilsner Urquell) and Pavel Prucha (quality control manager, Pilsner Urquell) for providing information on the brewing techniques used at Pilsner Urquell, to Michael Jackson for sharing his knowledge about the brewery, to Daniel Tobin of Bohemian Tours for reference material, and to Christian August, assistant brewmaster at Firestone Walker Brewing Co. in Los Olivos, California for helping with the research. Photos are by Bette Fauth, courtesy of Darryl Richman, except where noted.

References

1. Milos Wimmer, The chronological history of Plzen, http://www.zcu.cz/plzen/history.html (1996).
2. Brewery Museum of Plzen (1996).
3. Michael Jackson, Beer Companion (Running Press, Philadelphia, 1993).
4. Z. Knoflicek, et al. Pivovarske Muzeum V Plzni (Plzen, Czech Republic, 1995).
5. M. Belohlavek, et al., Plzen Guide-Book (City of Plzen Brewing Museum, Czech Republic, 1991).
6. G. Parker, ed., The Thirty Years War, rev. ed. (Toutledge & Kegan Paul, Boston, Massachusetts, 1987).
7. D.J. Boorstin, The Discoverers (Random House, New York, 1983).
8. J. Meadows, The Great Scientists (Oxford University Press, New York, 1992).
9. Dave Miller, Continental Pilsener (Brewers Publications, Boulder, Colorado, 1989).
10. Pilsner Urquell: Reading on Beer to the Anniversary of World-Known Mark, translated from Czech by Pilsner Urquell.
11. Milos Wimmer, Clickable map of historical Plzen, http://www.zcu.cz/plzen/map/map.html (1996).
12. Darryl Richman, "Pilsner Urquell: The Brewery -- Uncovering the Unusual," zymurgy 30, pp. 30-36 (Summer 1991).
13. Christine P. Rhodes, ed., Encyclopedia of Beer (Henry Holt and Company, New York, 1995).
14. Milos Wimmer, Pilsner Urquell home page, http://www.czu.cz/plzen/brewery/brewery.html (1996).
15. Pilsner Urquell brewery tour (1996).
16. Gregg Smith, Beer, A History of Suds from Mesopotamia to Microbreweries (Avon Books, New York, 1995).
17. Graham Lees, "From Shrine to Factory," What's Brewing, p. 12 (August 1996).
18. Jaroslav Rous and Pavel Prucha, Pilsner Urquell, personal communication, 1996/1997.
19. Milos Wimmer, The Brewery Museum, http://www.zcu.cz/plzen/landm/rn58.html (1996).
20. Randy Mosher, The Brewer's Companion (Alephenalia Publications, Seattle, Washington, 1994).
21. Christian August, assistant brewmaster, Firestone Walker Brewing Co., personal communication with BrewingTechniques, May 1997.
22. Peter A. Ensminger, "Light and Beer," zymurgy 19 (3), pp. 38-43 (1996).
23. Michael Jackson, personal communication, 1996.
24. David Coy, ed., 1996-97 North American Brewers' Resource Directory, compiled by the Institute for Brewing Studies (Brewers Publications, Boulder, Colorado), p. 378.

Peter Ensminger has been an all-grain home brewer for several years and is a member of the Salt City Brew Club of Syracuse, New York. Lisa Warnecke, who contributed one of the photographs, is the author's wife and also a member of the Salt City Brew Club.