Czech it out: Czech Dark Lager

01/24/2024

By Jack Horzempa

History of Czech Brewing

The geopolitical history of central Europe has been long and storied. For example, the nation of Germany was only started in 1871, making the United States older than Germany. Similarly, the nation of the Czech Republic was only started in 1993 from the peaceful split up of Czechoslovakia (which was formed in 1918). If instead we consider regions there is long continuity of Bavaria (now part of Germany) and Bohemia (now a region of the Czech Republic). Bohemia was a duchy/kingdom from the Middle Ages. A principal figure in Bohemian brewing was Duke (later Saint) Wencelas who was born in 903. After his death he was considered to be the patron saint of beer in Bohemia although he would have been drinking ales rather than lagers.

Bohemia borders Bavaria and brewing was important to both peoples. The history of lager brewing is an ongoing study but scholars believe that lager brewing started sometime in the 1400’s, perhaps in Bavaria which borders Bohemia. Lager brewing requires a yeast capable of fermenting under cold conditions, sometimes referred to as bottom fermentation. Modern genetic studies have determined that lager yeast (Saccharomyces Pastoriuse) was created via hybridization of ale yeast (Saccharomyces Cerevisiae) and Saccharomyces Eubayanus. It is thought that this hybridization occurred in central Europe with specific mention of Bavaria. Perhaps further research will be able to confirm this. But it is safe to say that in the time of Saint Wencelas the beers would have been ales. However, the beers in Bohemia do eventually transition from ales to lagers. Originally, lagers would have all been darker in color since the production of light-colored malt was a later development in Bohemia. The beer brand most associated with Czech brewing is Pilsner Urquell which was first brewed in 1842 and featured light colored malt (now referred to as Pilsner Malt).

During my visit to Prague in 2019 I visited the U Fleků Brewpub a number of times. U Fleků advertises they are the oldest continuously operating brewery in the Czech Republic with an origin date of 1499. When I was there, they only served one type of beer, a Czech Dark Lager. If you are ever in Prague, I strongly recommend going to U Fleků to drink their wonderful beer and in the warmer months a stay in their beautiful beer garden.

In later visits to the U Fleků website I discovered they now offer a Czeck Pale Lager (Bohemian/Czech Pilsner) beer along with their famous Czech Dark Lager.

Sensory Description of a Czech Dark Lager

The Czech Dark Lager is a relatively new beer style for American beer consumers. I am fortunate that lagers are popular with my local (Philadelphia area) craft breweries and a number of those craft breweries have produced this style, mostly on a rotating basis. I recently took a road trip to visit family and friends in Texas and during stops along the way I was able to drink Czech Dark Lagers both in Oklahoma City (Skydance) and in Vicksburg, MS (Key City) so it would seem that this beer is becoming more popular throughout America.

What distinguishes a Dunkel, Schwarzbier and Czech Dark Lager

American craft beer consumers are likely to be more familiar with the Dunkel and Schwarzbier beer styles. I am of the perspective that two qualities that distinguish these three beer styles is the level of roasty maltiness and the level of hop character (e.g., hop flavor).

For the aspect of a roasty malt flavor the spectrum from less (or no) roasty flavors to more roasty flavors is: Dunkel -> Czech Dark Lager -> Schwarzbier.

For the aspect of hop character, the spectrum of less to more is: Dunkel -> Schwarzbier -> Czech Dark Lager.

Another potential difference between these three dark beer styles is mouthfeel. All of the Czech Dark Lagers I had in the Czech Republic and most of the American brewed versions I had on draft had a creamy texture that I really enjoyed. This aspect may be due as much to the serving method (i.e., served via a Lukr side-pull faucet) as the beer itself but my homebrewed Czech Dark Lager has this quality as well (from the bottle conditioning process?).

I personally enjoy drinking all three of these dark lager styles but for my palate the Czech Dark Lager is my Goldilocks (just right) style with just a subtle (to none) roasty malt flavor and a pleasing hop flavor to complement the dark malt flavors. The key word for a properly brewed Czech Dark Lager is balance: It should not be too sweet, too bitter, too roasty, too much caramel,… with no one characteristic dominating the flavor profile.

Malt Flavor Profile

Just as with the Dunkel and Schwarzbier beer styles, an important feature of the Czech Dark Lager are the flavors associated with dark(er) malts. But wait, there’s more! An often-discussed aspect of Czech Brewing is their practice of decoction mashing. In Germany the practice of decoction mashing has in large measure been discontinued since it is both costly (energy intensive) and with contemporary malts is unnecessary since malts today are well modified. But the Czech breweries still continue the practice of decoction mashing because that is their tradition and because of the flavors that develop during the boiling of malt, and in the case of Pilsner Urquell they produce under-modified malt in house. The decoction mashing process which will be further discussed in the section about mashing.

Color and ABV/strength

Let’s learn some Czech:

Dark = Tmavý (or Tmavé)
Black = Černý

When it comes to beer strength, what we would typically associate with alcohol (ABV) strength, the Czechs instead describe the original gravity of the wort used to brew the beer. They have words for this but more commonly I have seen numbers in degrees Plato to describe the beers strength. In order of lower to higher strength:

10° or Výčepní
12° or Ležák
14° or Speciál (or Speziál)

You may on occasion see some values other than those listed above (e.g., 11°, 13°, …) but you get the general idea.

A mid-strength Czech Dark Lager could be called a Tmavý Ležák in the Czech Republic.

Malt

Malt type selection needs to achieve a number of goals:

The overall amount of malt to achieve the strength desired
The needed dark color: 17 – 35 SRM per the BJCP style guidelines
The dark malt flavors which can also be impacted by the mashing regime selected

In terms of base malts, a variety of Pilsner, Vienna, Munich (light and dark) can be selected. As regards caramel malts a CaraMunich malt can be selected (in versions I, II and III). And some dehusked (to minimize roast) Carafa malts (in version I, II and III) can be selected.

I have seen some recipes where the majority of the base malts is Pilsner Malt and a combination of very dark malts, and sometimes decoction mashing, are used to provide the needed color and desired flavors.

I have seen some recipes where no Pilsner Malt is used but Vienna Malt is instead the majority of the base malt along with a fair bit of Munich Malt and some crystal/roast malts.

And at the end of this article, you will see my malt selection which has equal proportions of Pilsner and Vienna Malt with a significant (but minority portion) of Munich Malts plus some caramel/roast malts.

I am of the opinion that you can achieve all of the needed Maillard Reaction Products (e.g., melanoidins) by using malts which are highly kilned/roasted (e.g., Vienna Malt, Munich Malts, CaraMunich Malt, dehusked Carafa Malt) since browning reactions occur from the high heats during the manufacture of the malt. This negates the absolute need for conducting a decoction mash. But feel free to conduct a decoction mash and select your malts accordingly.

One other technique that I have seen discussed is using a small percentage (e.g., 2% of the grain bill) of a specialty malt branded as Melanoidin Malt. The use of this specialty malt is advertised to mimic the flavors that are produced during decoction mashing.

Mashing

Decoction Mashing

I toured a number of Czech breweries during my visit to the Czech Republic, the Pilsner Urquell brewery conducts a triple decoction mash while the other breweries chose to conduct double decoction process. It is important to note that at the Pilsner Urquell brewery the produce their own malt in house and they purposefully produce an under- modified malt to be complementary for the decoction mashing regime.

A decoction mash is a step mash where some of the malt and mashing water is removed from the mash tun and that portion brought to a boil in a separate vessel. This decocted portion is boiled for a set period of time (e.g., 15 - 30 minutes) and very importantly this boiled mash needs to be constantly stirred to prevent scorching. This boiling operation results in Maillard Reaction Products (e.g., melanoidins) which is desired by the brewers who advocate for decoction mashing. The science of Maillard Reactions is discussed in the section on Browning Reactions. In addition to the development of these products the heat stress from this boiling will also develop Strecker Aldehydes which have been associated with beer instability (i.e., beer staling). Perhaps a situation of the ‘good’ overcomes the ‘bad’? This decoction process is repeated to achieve the target for a double or triple decoction.

A detailed description of a triple decoction (the Pilsner Urquell schedule) is available in this article:

https://www.morebeer.com/articles/Pilsen_Beer

One of the breweries I toured in the Czech Republic was Staropramen and on their website they discuss decoction mashing:

“4. DECOCTION MASHING

Decoction mashing is Czech to the bone. It is a procedure where a portion of the mash is taken to another vessel, boiled separately and then brought back. At Staropramen, we repeat this procedure twice (double decoction). Decoction makes the beer body smooth and rich and adds a deep golden color. Originally, decoction method was invented to ensure brewing effectiveness during an age when no thermometers existed and malt was darker making the sugars harder to extract.

Decoction mashing perfectly sums up the Czech brewing tradition. Who in his right mind would regularly use a method that requires an additional vessel, extra time and more effort to brew a better beer? Only the beer-crazed Czechs, of course!”

https://www.staropramen.com/blogs/beerpedia/all-categories/what-makes-a-czech-beer-czech

For the interested student, an article on decoction mashing:

https://www.morebeer.com/articles/Decoction_Mashing

Single Temperature Infusion Mashing

The predominant method for mashing in Great Britian is single temperature infusion mashing also referred to as “British infusion mash”. Brewing in America followed the British brewing tradition so infusion mashing was common. This carried on to the majority of craft breweries today. A minority portion of craft breweries have implemented a brewhouse that can conduct decoction mashing. Since contemporary malts are well modified there is no need for a decoction mash to achieve proper starch conversion to sugars. There is no reason that a commercial brewery or homebrewer needs to conduct decoction mashing so it is very much optional unless per Staropramen you want to be a “beer-crazed Czech”. You will see in my recipe that I chose to conduct a single temperature infusion mash and via proper choice of a malt bill plenty of dark malt flavors result in the finished beer.

Boiling

A typical boil length for homebrewed beers is 60 – 90 minutes. I have seen it discussed that for very long boil times Maillard Reactions take place but I have also seen this refuted. Regardless, it seems like conducting a very long boil (e.g., many hours) to encourage Mailliard Reactions is not an efficient technique to achieve this goal. You are better off just selecting a proper grain bill and/or conducting decoction mashing in my opinion.

Browning Reactions

When it comes to brewing there are a number chemical reactions that chemists refer to as “Browning Reactions”. I will try and discuss these topics in simpler terms but unfortunately some chemistry is involved for completeness (my apologies to those who were not fond of chemistry in high school).

Caramelization

This is likely the type of browning reaction that is most familiar to homebrewers. When high heat is applied to sugars, they decompose and rearrange forming new sugars. Many of these are amber to deep brown and give the taste of caramel. Each of these sugars has a different color, smell, and taste. Caramelization can be ‘added’ to homebrewing simply by using some caramel malts to the grain bill and can be used by extract brewers via a simple steep process. The caramelization has already occurred at the malting company by the high heats applied during the kilning/roasting process, which caramelizes the sugars naturally found in the malt.

The production of caramel/crystal malts results in both a darker color to the malt (and therefore it will darken the resulting beer) and also adds some flavors. For example, Briess 80L Carmel Malt is described to add flavors of “dried fruit, candy-like sweetness”.

Another brewing ingredient that contributes caramelization to beer is caramelized dark candi sugar syrup, which is typically used to brew Belgian style beers. I use caramelized dark candi sugar syrup (i.e., D-180 Candi Syrup) when I homebrew my Belgian Quad beers. You can see my recipe here:

https://www.morebeer.com/articles/Belgian_Quad

Another aspect of caramelization is boiling via a high heat source (e.g., a gas flame). During my tour of the Pilsner Urquell brewery the tour guide discussed they used high heat flames (600 °C/572 °F) which added caramelization to the boiling wort. In homebrewing the effect of caramelization is increased if a partial boil is conducted when boiled with a high heat source (e.g., a propane burner).

Maillard Reactions

A French chemist, Louis Mailliard, first described this browning reaction in 1912. Consequently, his name is affixed to this chemical reaction. This process is a bit more complicated than caramelization in that it involves more than sugars. It involves the reaction of free amino groups (e.g., amines, amino acids, peptides and proteins) with reducing sugars in the presence of heat. An often-used description of Maillard Reactions is the browning that occurs when a steak is grilled:

“As the meat is heated, the amino acids react with the reducing sugars that are present in the meat, and it creates numerous new compounds such as Pyrazines, Furans, and Thiophenes.”

Brewers carry out Maillard Reactions when boiling malt during the decoction mashing step. The malt in the mash contributes amino acids and sugars and the boiling process contributes the heat. How long you decide to boil will be impactful here.

The flavor contributions from Maillard Reactions are typically associated with ‘positive’ flavors. For example, reaction products like melanoidins are often described as adding toasty/malty flavors to the resulting beer. Other chemical reactions are occurring during the boil with one example being the development of Strecker Aldehydes. Some studies indicate this could shorten the shelf-life and develop off-flavors to the resulting beer.

Hops

The typical hop used in Czech Brewing is Saaz hops. There are other Czech grown hops, for example I have enjoyed some beers featuring Sladek hops, but for a classic Czech Dark Lager I recommend you utilize Saaz hops especially for the flavor/aroma additions. For pragmatic reasons I personally choose to use German Magnum hops for the bittering addition since Saaz hops are so low in alpha acids content.

The hop schedule should be a combination of a bittering addition (e.g., beginning of the boil), a flavor addition (e.g., last 20-15 minutes of the boil) and an aroma addition (e.g., towards the end of boil).

Yeast

The conventional wisdom is that you need a lager yeast of Czech origin to properly produce this beer style. I have limited experience here since I have solely used WLP802 (Czech Budejovice Lager Yeast) to ferment my five batches (so far) of a Czech Dark Lager. WLP802 is stated to be sourced from a brewery in the southern Czech Republic. I have always been pleased with the yeast both in terms of performance (e.g., time to reach final gravity, etc.) and how the final product tastes.

There are other lager yeast strains with Czech origins such as WLP800 (Pilsner Lager Yeast), Wyeast 2278 (Czech Pils Yeast), Wyeast 2001-PC (Pilsner Urquell H-strain), and Imperial Yeast L28 (Urkel Lager Yeast).

So, do you really need a lager yeast sourced from a brewery in the Czech Republic? In the past I would have answered yes to that question but in a recent article, I read that a brewery in Prague that I respect uses W-34/70 as their house lager yeast. Given this new knowledge I am inclined to expand my thinking here and suggest that using a lager yeast strain sourced from the Czech Republic is not an absolute requirement.

Fermentation/Lagering

Yeast strain selection is an important consideration but fermentation considerations are equally important. What temperature will you ferment the beer? How long for primary fermentation before transferring to the lagering vessel? How much yeast do you pitch?

All of those above topics and more are addressed in the article How to Make Lager Beer:

https://www.morebeer.com/articles/Lager_Beer

The above article also discusses other important aspects of lagering (e.g., temperatures, duration).

Brewing Water

The brewing water in the Czech Republic is soft, very low in minerals. Below is a suggested water profile for brewing Czech beers courtesy of Bob Hall at a past National Homebrewers Conference:

Carbonates: 15

Calcium: 7

Sulfates: 5

Magnesium: 2

Sodium: 2

Chloride: 2

The above is a very soft water profile. I personally choose to use my filtered municipal tap water diluted in a 50/50 ratio using distilled water I purchase at my local Walmart. I am very happy with how my beer turns out despite not using super soft water.

My Czech Dark Lager recipe: Dark Angel

As previously discussed, my wife and I visited the Czech Republic in 2019 and we stayed in a small hotel in the Andel neighborhood of Prague. The word Andel translates to angel in English. My wife was inspired by our visit to brand my homebrewed Czech Dark Lager as Dark Angel and she even made the effort to create a striking bottle label with this branding, which you can see below.

Batch Size: 5.5 gallons

Target OG: 1.052

Target FG: 1.013

Color: 22 SRM

Target Bitterness: 34 IBUs

Ingredients (Note: assumes a 75% brewhouse efficiency):

3 lbs. Pilsner Malt
3 lbs. Vienna Malt
2 lbs. Light Munich Malt
1 lb. Dark Munich Malt
0.5 lbs. CaraMunich I
0.5 lbs. dehusked Carafa II
0.5 ounces German Magnum Hops (14% AA)
2 ounces Czech Saaz Hops (3% AA)
Lager yeast (my preference is WLP802)

Additional items:

1 tsp. rehydrated Irish Moss flakes (last 15 minutes of boil)
½ tsp. Wyeast yeast nutrient (last 10 minutes of boil)

Directions:

Mash at a water-to-grist ratio of 1.5 qts/lb. Adjust brewing water to be consistent with Bohemian water profile and add lactic acid to achieve a mash pH of 5.2 – 5.4 (if needed). Mash at 153 °F for 60 minutes. Sparge until approximately 7 gallons of wort is achieved (tailor amount based upon your boil off rate to obtain 5.5 gallons of wort post boil).

Boil vigorously for 60 minutes in an uncovered brew kettle adding the German Magnum hops at the beginning of boil. Add 1 ounces of Czech Saaz hops for the last 15 minutes for a flavor addition along with 1 tsp. of rehydrated Irish Moss flakes. With 10 minutes remaining in the boil add ½ tsp. of Wyeast yeast nutrient. At end of boil add 1 ounce of Czech Saaz hops for an aroma addition. I choose to conduct a 15 minute hop-stand.

Ferment cool per the yeast vendor’s recommendation until final gravity is achieved; conduct a diacetyl rest towards the end of fermentation if you prefer. Transfer to a lagering vessel (e.g., carboy, keg) and lager cold (e.g., 35 °F) for about five weeks. Package when lagering is complete.

Partial mash recipe

Ingredients (Note: assumes a 75% brewhouse efficiency):

2.3 lbs. Briess Pilsen Dried Malt Extract
3 lbs. Vienna Malt
2 lbs. Light Munich Malt
1 lb. Dark Munich Malt
0.5 lbs. CaraMunich I
0.5 lbs. dehusked Carafa II
0.5 ounces German Magnum Hops (14% AA)
2 ounces Czech Saaz Hops (3% AA)
Lager yeast (my preference is WLP802)

Additional items:

1 tsp. rehydrated Irish Moss flakes (last 15 minutes of boil)
½ tsp. Wyeast yeast nutrient (last 10 minutes of boil)

Directions:

Mash grains at a water-to-grist ratio of 1.5 qts/lb. Adjust brewing water to be consistent with a Bohemian water profile and add lactic acid to achieve a mash pH of 5.2 – 5.4 (if needed). Mash at 153 °F for 60 minutes. Sparge until approximately 5 gallons of wort is achieved and then add 2.3 lbs. of Dried Malt Extract and perhaps some top off water to achieve a total of 7 gallons (tailor amount based upon your boil off rate to obtain 5.5 gallons of wort post boil).

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