2 Profile of the Pilsener Style

While the Pilsener style of beer is pale-colored, highly carbonated, light to medium in body, and clean flavored with a distinct hop aroma, these characteristics vary widely throughout Europe. In preparing to brew his own Pilsener, a brewer would do well to understand this range and how the style becomes lighter and more delicate farther away from the Pilsener homeland of Bohemia.

PROFILES

- Pilsner Urquell -

Pilsner Urquell must be taken as the standard against which all Bohemian beers—and indeed all Pilseners world-wide—are measured. It is therefore particularly useful to look at some of its characteristics. Keep in mind, however, that some of the most important aspects of the beer’s flavor, such as its hop aroma, cannot be quantified in any simple way. The numbers do not tell the whole story.

Original Specific Gravity	1.049 (12.1 °P)
Apparent Final Gravity	1.014 (3.7 °P)
Apparent Degree of Attenuation	69%
Real Degree of Attenuation	55%
Reducing Sugars (as maltose)	1.4%
pH	4.6
Bitterness	11.5 HBUs per 5 gallons; 43 IBUs
Color	4.2 °L
Alcohol Content	3.6% w/v; 4.5% v/v

The chief observation to be made about these numbers is that while some of them (such as alcohol content) are squarely in the middle of the range for Pilsener beers, others are on the extreme edge. The content of reducing sugars is moderate for lager beers, but rather high for the Pilsener style. Original gravity is only a little higher than average, but the attenuation is lower than for most Pilseners. The beer is best described as moderately attenuated. The numbers related to this phenomenon reflect a high content of proteins and unfermentable carbohydrates, which accounts for the full body (mouthfeel) of Pilsner Urquell. Subjective evaluations confirm the full, rich character of the flavor, which is reinforced by a caramel note in the aroma.

The impression of smoothness and sweetness is enhanced by the relatively high level of diacetyl in the beer, which is 0.15 ppm. By modern brewing standards this is on the edge of being objectionable, especially for lagers. In this full-flavored beer, diacetyl is not identifiable as a buttery or butterscotch note, but its level is well over the taste threshold (0.1 ppm) and undoubtedly contributes to the flavor.

The sweet, smooth flavor and palate fullness of Pilsner Urquell is balanced by its hop character, which chemical analysis can only partly reveal. The beer is very bitter, at 43 International Bitterness Units (IBU, which is the same as parts per million of isohumulone). Assuming a 25 percent hop utilization, which is about average with whole hops, this translates into 11.5 Homebrew Bittering Units (HBU) [also called Alpha Acid Units (AAU)] per five gallons. Pilsner Urquell is certainly the most highly-hopped lager I have ever tasted. The other component of its hop character—the aroma—cannot be quantified by analysis of a single component. Nonetheless, it is extremely high, on a par with the hoppiest pale ales.

Another factor in the flavor balance of some beers is their acidity. This can be measured in several ways. The most common is pH, which reflects the actual concentration of hydrogen ions in the beer. Unfortunately, pH does not correlate very well with flavor. At 4.6, the pH of Pilsner Urquell is high but within the normal range for a lager beer. The titratable acidity (a better measure from a flavor standpoint) is, regrettably, not available for this beer. In any case, even the total titratable acidity is a rather crude parameter since various organic acids have widely differing taste thresholds and flavors. In most finished beers, lactic acid is present in the highest concentration, but this acid has a high flavor threshold and a mild flavor; hence, it has little impact in the taste of Pilsener and most other beers. Kraeusened beers also contain relatively high concentrations of pyruvic acid (as well as acetaldehyde and other “young beer” compounds). However, the most significant acid from a flavor standpoint is acetic acid, which is volatile and has a much sharper flavor, as well as a lower threshold than lactic acid. According to a study performed by Anheuser Busch, most German Pilseners contain acetic acid at levels at or above the taste threshold of 160 ppm. By contrast, no American Pilsener even approaches the threshold level of this compound, which may partly explain why our Pilseners lack the pungency of many Continental examples, including the original.

In terms of appearance, Pilsner Urquell is darker than most of its descendants, measuring 4.2 degrees Lovibond. Subjectively, this is best described as dark yellow or light golden, but demonstrably darker than the pale yellow of most German and Dutch Pilseners. Haze data are not available, but the beer appears sparkling clear when fresh, and because precipitated protein has dropped out during its three-month period of cold lagering, it is practically immune to chill haze, despite its high protein content.

Terminal gravity correlates with the body and smoothness of the beer, as does protein content, which also affects head retention. The protein content of Pilsner Urquell is 0.45 percent, which is quite moderate for an all-malt Continental beer but half again as high as a typical American lager. Objective data on foam stability are not available for this beer, but subjectively, it is excellent.

In summary, Pilsner Urquell has high carbonation, and when poured forms a thick, long-lasting head. Its aroma is dominated by Saaz hops, but the malt also comes through, so its flavor is strong and well-balanced. The malty sweetness includes more than a hint of caramel, but it is well complemented by a strong bitterness without the least roughness or bite. Body is very full. Overall, the beer is exceedingly smooth but has great depth of flavor. It is truly a world classic.

- German, Dutch and Scandinavian Pilseners -

While dozens of other pale lagers are brewed in Czechoslovakia (including such notables as Budvar and Micelovice, the antecedents of Budweiser and Michelob respectively), very few are exported to North America, and analytical data on these beers are almost impossible to find in English-language brewing publications. For this reason, and also because it is the prototype of the style, Pilsner Urquell stands both by right and necessity as the representative of Bohemian beer. But there is much more information available for the beers brewed in West Germany, the Low Countries, and Scandinavia. I will discuss these Pilseners in general terms by comparing them to their Czech original. This comparison shows that the objective data correlate quite well with subjective taste perceptions, though again, the numbers do not tell the whole story.

German

Original Specific Gravity	1.047-1.049 (11.7-12.0 °P)
Apparent Final Gravity	1.008-1.012 (2.0-3.0 °P)
Apparent Degree of Attenuation	74-83%
Real Degree of Attenuation	59-67%
Reducing Sugars (as maltose)	N.A.
PH	4.2-4.6
Bitterness	8.0-9.9 HBUs per 5 gallons; 30-37 IBUs
Color	3.0-3.5 °L
Alcohol Content	3.6-4.2% w/v; 4.5-5.2% v/v

Dutch and Scandinavian

Original Specific Gravity	1.042-1.047 (10.5-11.5 °P)
Apparent Final Gravity	1.007-1.010
Apparent Degree of Attenuation	75-82%
Real Degree of Attenuation	60-65%
Reducing Sugars (as maltose)	N.A.
pH	4.2-4.6
Bitterness	5.4-7.5 HBUs per 5 gallons;
	20-27 IBUs
Color	2.5-3.0 °L
Alcohol Content	3.4-4.0% w/v; 4.2-5.0% v/v

These Continental Pilseners are better attenuated than Pilsner Urquell, 75 to 82 compared to 69 percent respectively. This correlates quite well with the “dryer” taste of these beers. The greater the attenuation, the lower the content of reducing sugars and unfermentable carbohydrates in the finished beer. Alcohol content is roughly equal to that of Pilsner Urquell, but the alcohol content of a beer can vary over a wide range without affecting its flavor. Of greater significance is the diacetyl content, which, thanks to modern fermentation techniques, can be as low as 0.02 ppm. Like the lower content of carbohydrates, this translates into a lower sweetness, as well as a less complex aroma.

The German Pilseners have a protein content comparable with the Czech beer, varying between 0.45 and 0.62 percent. As might be expected, they seem subjectively to have good body, though in most cases not as much as the Bohemian brew. In general, the German Pilseners can be described as clean, perhaps even “bracing,” with full body and malty flavor, but not as rich and sweet as Pilsner Urquell.

By way of compensating for the lower sweetness of a German Pilsener, the bitterness also is lower. German beers with this level of bitterness, however, are not subjectively less bitter than Pilsner Urquell. The balance between sweetness and bitterness is very much the same. Hop aroma is also strong and seems to be even more predominant in the “nose” of some of the German beers. This may be because most German Pilseners do not have a caramel flavor and aroma and are low in diacetyl.

Finally, German Pilseners also are paler in color than Pilsner Urquell. They usually are sparkling clear though I have run across examples that threw a chill haze in the refrigerator. This characteristic bespeaks shorter processing times, but it is only a problem if the beers are served very cold. Foam retention is excellent, as would be expected from an all-malt beer with a high protein content.

The Dutch and Scandinavian Pilseners are similar to the German examples in that they are very well-attenuated. The original gravities are somewhat lower, however. Given the same degree of attenuation, this obviously translates into a lower content of reducing sugars and unfermentable carbohydrates in the finished beer, a dryer flavor and a less full palate. Furthermore, the protein content of these beers may be as low as 0.3 percent, due to the use of adjuncts in the grist. Diacetyl is very low, typically 0.05 ppm or less. The net result is a beer which, in comparison to other Continental Pilseners, is very light in both body and flavor.

To keep things in balance, the hop character of these beers is likewise diminished. Hop aroma is also considerably lower, in keeping with the more delicate character of the beer.

In appearance, these beers are very clear indeed and are usually paler than German Pilseners. The low protein content means that foam retention is not as good as for the all-malt Pilseners, though it is usually adequate in a clean glass.

In conclusion, I want to repeat that the numbers never tell the whole story. Obviously, if you want to brew a particular style of Pilsener beer, you have to stay within the major specifications, e.g., original gravity, attenuation, color, and so on. But at best, those numbers can give only some indication of how the finished beer will taste. Flavor depends greatly on aroma, and aroma is scarcely accounted for in the numbers I have cited. Beers brewed to the same specifications can therefore vary significantly, depending on the particular raw materials and brewing methods used.