Czech Dark Lager: Prague’s dunkel

The more I drink craft beer, the more I find myself gravitating towards lagers. The crisp, clean, pale lagers get all the attention, but the classic dark lagers are what I find most satisfying. While Czech dark lager was just added to the Beer Judge Certification Program (BJCP) Style Guidelines in 2015, I have been encouraged to see more of the U.S. craft lager producers making them. I wanted to add this style to the 2004 Style Guidelines but others seemed unfamiliar with it because we didn’t see any imported or domestic examples. Fortunately, times have changed.

To understand Czech dark lager, we first have to understand how Czech beer (pivo) is categorized. Czechs describe their beer by color (pale, amber, dark – svělté, polotmavé, tmavé – but also may call their dark beers černé, or black) and strength in degrees Plato original extract (starting gravity). So, you might refer to a beer from a certain brewery as a tmavé 12, for instance. As an approximation, 1 °Plato is about 4 gravity points, so a 12 °P beer has an original gravity of 1.048.

The different strengths are also grouped into three broad gravity classes: Draft, lager, and special – výčepní, ležák, speciální. The draft strength beers are 7–10 °P, but may be bottled. The lager strength beers are 11–12 °P and are aged but aren’t necessarily bottom-fermented. The special strength beers are 13–20 °P, but aren’t that rare. Yes, their terms can be confusing for English speakers, but once you understand their system, the beers are easy to understand.

As an aside for purists, Czech beers are actually measured in degrees Balling, since the scale was invented by a Czech chemist in 1843. But degrees Balling, degrees Plato, and Brix are essentially interchangeable and are used in different industries and locations. If you really want to know, Balling was first and used a reference temperature of 17.5 °C (63.5 °F); Plato came later as a refinement and used 20 °C (68 °F). At the precisions used in brewing, the difference is negligible. I use degrees Plato because it is the most common term used throughout the commercial brewing industry.

Czech dark lager is BJCP style 3D in the Czech Lager style category. This style actually encompasses dark lagers in two strength categories, with a range of 11–15 °P (OG 1.044–1.060). It was a compromise to allow a wider range of Czech beer to be described, but understand that Czechs will use the color and the gravity as the primary descriptors.

Czech Dark Lager History

The Czech Republic (a.k.a. Czechia) as a modern state dates to 1993, after Czechoslovakia broke up after the fall of communism. But the lands of Bohemia and Moravia, which make up most of the Czech Republic, have a much longer history. Beer has been brewed in this area for over a thousand years. Bohemia is known for its hops, and Moravian barley is well regarded. The U Fleků brewery in Prague opened in 1499, and makes the best-known example of the style today, a 13 °P (1.053 SG) special.

Prague, the national capital, is in Bohemia, as are other major beer-producing towns of Plzeň (Pilsen), České Budějovice, and Žatec. Bohemia is just to the east of the northern Bavarian region of Franconia in Germany, which also explains some of the similarities between German and Czech styles. As with the Munich dunkels of Germany, the Czech dark lagers are a traditional brown beer style that have held on into modern times.

Before pale lagers were introduced in 1842 in Prague, beers were generally darker in color and clarity didn’t matter as much since beer was not drunk from glassware. But don’t make the mistake of assuming this means “lagers were invented” in 1842, and therefore dark lagers came later. Remember that lagering is a cold maturation process, and that lager yeast (Saccharomyces pastorianus) are bottom-fermenting — lager as a type of beer refers to the use of both. The lagering process was used hundreds of years before this time, although characterization of pure strains of yeast was a later advancement.

Sensory Profile

Czech beer has a national character that is a bit different from the more well-known German lagers. Czech beer tends to have a greater amount of unfermented extract in the finished beer, which gives it a fuller body and mouthfeel, and a richer, slightly more complex flavor profile. Czech yeast strains are not always as clean as German counterparts, and can have diacetyl at a near sensory threshold level. These characteristics are present in Czech dark lager.

From a judging standpoint, this style is quite broad — no one beer defines the style. We’ve already mentioned the range of strength, but the balance of hops and the flavor of the darker malts are two other areas of variation. The malt can have caramel and roast flavors from low to moderate, which add character to the rich Munich-like base malt flavors. Malt flavors such as caramel, toast, nuts, licorice, dried dark fruit, chocolate, or coffee may be present.

The caramel flavors will have some sweetness, naturally, but the beer shouldn’t seem overly sugary-sweet. It really needs the rich flavor of malt as the base, not something neutral. Likewise, any roast qualities should be restrained — they shouldn’t have burnt notes, or make you think you are drinking a porter or stout. The caramel and roast should accentuate and enhance the rich base malt flavors, not be a substitute for them, and they provide much of the defining malt flavor for the style.

The hop aroma, flavor, and bitterness are somewhat variable, which also affects the balance. Traditional versions often have a sweeter or less bitter balance, while modern craft versions are more hoppy and bitter. A spicy hop aroma and flavor may or may not be present, but should complement the malt. There should be some residual sweetness, but the bitterness level can sometimes keep it from being too obvious. There may be some darker fruit flavors, like plums or berries, and trace buttery diacetyl is sometimes present, but should be more as a mouthfeel enhancer rather than a flavor.

The beer should be smooth and mouth-filling without seeming heavy or cloying. It may have a creamy texture, and carbonation is moderate to low. Alcohol warmth may be present in stronger examples, since the style can range from 4.4 to 5.8% ABV. The color ranges from dark copper to almost black, but is usually clear with a good head stand. In general, I think it has the character of a somewhat hoppy Munich dunkel or malty schwarzbier.

Brewing Ingredients and Methods

Czech brewers traditionally prefer decoction mashes, most often double decoctions, as they feel it produces beer with their national character. While Germans have largely switched to step mashes, Czechs will still perform decoction mashes with modern malts because of flavor and mouthfeel effects. Some brewers will use step mashes with a higher percentage of richer malts if a decoction mash is not to be employed.

The well-known U Fleků beer is reported to use four malts. When thinking about recipe formulation, I’d say that four classes of malts are needed in this style. A base malt, like Pils or Vienna malt, should be 50–60% of the grist. A richer malt, like Munich or dark Munich, can be 20–40% of the grain bill. A caramel-type malt, like Caramunich® II or III, can be 5–15%, and a darker malt, like Carafa® Special II or III, around 5% of the grist. While I think four malts is sufficient, you may also choose multiple malts within each of the four classes if you wish. This general template gives you quite a bit of room for personalizing your recipe.

When using darker malts, try to use the debittered or huskless versions since you don’t want sharp, burnt, or acrid flavors. The debittered roasted malts have a smooth roast flavor without the harsh bite. Michael Jackson noted that some breweries use coloring agents instead, but that he thought they tasted inferior. I would use German or Czech malts throughout, as they are more likely to have the traditional flavors for the style.

Czech hops (especially the Saaz variety) are characteristic for the style, particularly in the flavor and aroma. Three additions (bitterness, flavor, and aroma) are traditional, but dry hopping is not a traditional method. The level of late hops can vary quite a bit with commercial examples, and the balance of bitterness-to-malt is another stylistic choice. I prefer this style a little on the hoppy side to help differentiate it from Munich dunkels in competition.

Czech beers normally are brewed using water with a very low mineral content; sulfates in particular are typically avoided as they can sharpen the finish and clash with the hops. A Czech or a clean, malty German yeast strain works best, as Czech beers often have a very small bit of residual unfermented extract (sugars and other dissolved matter, basically implying a higher final gravity). Czech fermentation practices are often a bit cooler than German practices and lagering can take longer. Patience is key during the conditioning phase of production.

Homebrew Example

My example is a lower-gravity modern Czech dark lager, coming in as an 11 °P (1.044 SG) beer. I prefer maltier versions of this style a touch stronger but this version is on the hoppy side to help distinguish it from its German cousin. When I wrote about Czech amber lager in the July-August 2016 issue, I included a classic double decoction mash program. That same mash schedule could be used for this beer. You can find that full article and recipe at https://byo.com/article/czech-amber-lager/. As an alternative, I’m presenting a step infusion mash program in this recipe that is a little easier to execute.

I’m selecting from the four classes of malt I mentioned in the ingredients and methods discussion. Vienna is the base malt, dark Munich is the rich malt, Caramunich® III is the caramel malt, and Carafa® Special II is the dark malt. These are all on the richer side, which is a choice made because of the mash schedule. German malts are fine for this recipe; I would not use North American malts because the flavor profile wouldn’t be the same as their European counterparts.

Three additions of Czech Saaz hops provide the authentic hop character, and the bitterness is a bit higher to help balance the malt. I’m using quite a few late hops, so there should be noticeable hop flavor and aroma. If you can’t get good fresh Czech Saaz hops, I’ve found that U.S. Sterling hops are an acceptable substitute.

Czech beers are made with low mineral water, which suits my typical reverse osmosis (RO) water method just fine. A little calcium chloride will help with the rounded malt flavor, while assisting mash performance. This amount is half what I typically use in most styles as a nod to the lower mineral Pilsen profile.

I’m calling for Czech Budejovice lager yeast, and using a Czech fermentation schedule with a cool fermentation and a long lagering time. If you can’t find this yeast, the cleaner German W-34/70 strain (liquid or dry) will also produce a nice beer. Please don’t do anything to try to accentuate a
diacetyl character – it really shouldn’t be noticeable.

This recipe allows for customization. You can increase the strength, decrease the bitterness, decrease the late hops, or adjust the caramel and roast percentages based on your personal preferences. As long as you follow the general guidelines I’ve given, you will likely make a beer that fits within the broad style. And I’d really like to try it.

Czech Dark Lager

(5 gallons/19 L, all-grain)
OG = 1.044 FG = 1.013
IBU = 26 SRM = 27 ABV = 4.1%

Ingredients
6 lbs. (2.7 kg) Continental Vienna malt
1.75 lbs. (794 g) Continental dark Munich malt (11 °L)
1.5 lbs. (680 g) Caramunich® III malt (57 °L)
8 oz. (227 g) Carafa® Special II malt (430 °L)
4 AAU Czech Saaz hops (60 min.) (1 oz./28 g at 4% alpha acids)
6 AAU Czech Saaz hops (15 min.) (1.5 oz./43 g at 4% alpha acids)
1.5 oz. (43 g) Czech Saaz hops (1 min.)
White Labs WLP802 (Czech Budejovice Lager), Wyeast 2278 (Czech Pils), or SafLager W-34/70 yeast
3⁄4 cup corn sugar (if priming)

Step by Step
If using a liquid strain, two or three days before brew day, make a 2-qt. (2-L) yeast starter, aerating the wort thoroughly (preferably with oxygen) before pitching the yeast. Use two sachets if using a dry yeast strain.

On brew day, prepare your ingredients: Mill the grain, measure your hops, and prepare your water. This recipe uses reverse osmosis (RO) water. Add ¼ tsp. 10% phosphoric acid per 5 gallons (19 L) of brewing water, or until water measures pH 5.5 at room temperature. Add 0.5 tsp. calcium chloride (CaCl2) to the mash. Use enough water to have a moderately thick mash (1.5 qts./lb. or 3.1 L/kg).

This recipe uses a step mash program with a mashout. Mash in the Vienna and dark Munich malts at 131 °F (55 °C) and hold for 15 minutes. Raise the mash temperature to 149 °F (65 °C) and rest for 30 minutes. Raise the mash temperature to 158 °F (70 °C) and rest for 30 minutes. Begin recirculating, add the Caramunich® and Carafa® malts, mix gently without disturbing the grain bed, then raise the mash temperature to 170 °F (77 °C) for mashout, recirculating the whole time. Hold at mashout temperature for 15 minutes.

Sparge slowly with 170 °F (77 °C) water until 6.5 gallons (25 L) of wort is collected.

Boil the wort for 60 minutes, adding the hops at times indicated in the recipe. At the end of the boil, let the wort settle for 10 minutes.

Chill the wort to 46 °F (8 °C). Oxygenate the wort, then pitch the yeast starter. Start fermentation at 46 °F (8 °C) but allow the temperature to rise to 50 °F (10 °C) until fermentation is complete. Rack the beer. Lager the beer at 32 °F (0 °C) for 11 weeks, then fine with gelatin or filter.

Prime and bottle condition, or keg and force carbonate to 2.5 volumes. If bottle conditioning, warm condition the beer at 68 °F (20 °C) for one to two weeks before chilling.

Czech Dark Lager

(5 gallons/19 L, extract with grains)
OG = 1.044 FG = 1.013
IBU = 26 SRM = 27 ABV = 4.1%

Ingredients
3.6 lbs. (1.6 kg) Pilsen liquid malt extract
1.4 lbs. (635 g) Munich liquid malt extract
1.5 lbs. (680 g) Caramunich® III malt (57 °L)
8 oz. (227 g) Carafa® Special II malt (430 °L)
4 AAU Czech Saaz hops (60 min.) (1 oz./28 g at 4% alpha acids)
6 AAU Czech Saaz hops (15 min.) (1.5 oz./43 g at 4% alpha acids)
1.5 oz. (43 g) Czech Saaz hops (1 min.)
White Labs WLP802 (Czech Budejovice Lager), Wyeast 2278 (Czech Pils), or SafLager W-34/70 yeast
3⁄4 cup corn sugar (if priming)

Step by Step
Start with 6 gallons (23 L) of brewing water in the brew kettle; heat to
158 °F (70 °C).

Steep the Caramunich® and Carafa® malts in a mesh bag for 30 minutes. Remove and rinse grains gently. Turn off heat.

Add the malt extracts and stir thoroughly to dissolve the extract completely. You do not want to feel liquid extract at the bottom of the kettle when stirring with your spoon. Turn the heat back on and bring to a boil. Boil the wort for 60 minutes, adding the hops at the times indicated in the recipe. At the end of the boil, let the wort settle for 10 minutes.

Chill the wort to 46 °F (8 °C). Oxygenate the wort, then pitch the yeast starter. Start fermentation at 46 °F (8 °C) but allow the temperature to rise to 50 °F (10 °C) until fermentation is complete. Rack the beer. Lager the beer at 32 °F (0 °C) for 11 weeks, then fine with gelatin or filter.

Prime and bottle condition, or keg and force carbonate to 2.5 volumes. If bottle conditioning, warm condition the beer at 68 °F (20 °C) for one to two weeks before chilling.

Tips For Success:
While a step mash will help the yeast acheive a full attenuation with this beer, hitting the various temperatures precisely is not crucial. A few degrees off in either direction will not ruin things. Another option is to just slowly heat the mash from 131 °F (55 °C) up to 170 °F (77 °C) over the course of 60–75 minutes to achieve a similar effect.

Yeast health and fermentation temperature control are always two crucial factors when brewing lagers. Make sure to pay close attention to these details in order to produce a clean example of this style of beer. A small addition of yeast nutrients near the end of the boil will often be a good thing as well.

Written by Gordon Strong