If you’ve had beer, you’ve almost certainly had a Bohemian (Czech) Pilsner or one of its many, many offspring and cousins. This was the first real pale lager, and it was not only immediately successful, it was endlessly copied and modified based on local brewing conditions. It also remains one of the great beer styles of the world in its own right, and when well-brewed, it’s a real showcase for the essential flavors of its ingredients. Brewing it is easier and harder than people think, and this is one of the rare times that I’ll give you the advice to go more extreme than you might be comfortable with!
Style
This is one of those beer styles we can tie to a specific place, time, and even name. German brewer Josef Groll brewed the first Pilsner in (unsurprisingly) Plzen in 1842, taking advantage of the region’s soft water, abundant herbal hops, a new malt kilning technique that allowed for exceptionally pale beers, and this new-fangled thing called “lager” yeast, a cleaner-fermenting alternative to traditional yeasts. The net result was a beer that has restrained fermentation character and a clean but complex biscuity maltiness and an absolute avalanche of hops without harsh bitterness. We can take advantage of all of the same ingredients Groll used with nothing more than a trip to the homebrew supply shop (lucky us), with one exception: water. The water profile of your beer is essential to making a true Bo Pils, and while you can get away with not adjusting your water, you’ll be aiming at a much, much smaller target.
Ingredients
This is a simple beer, and its recipe is simple. Start with 10 pounds (4.5 kg) of floor-malted Pilsner and add 8 ounces (227 g) of acidulated malt. That’s it. The floor-malted Pilsner malt is a little more expensive, but you’ll get much more flavor out of it! Be sure, though, that it’s floor-malted Pilsner malt, and not just standard Pils malt—maltsters often sell both. As for the acidulated malt, you’re not actually adding “sourness” to your beer (or even tartness)—that’s simply to help keep you in the proper pH range during the brewing process, since we’ll be working with soft or diluted water.
You’re going to add an absurd amount of hops to this beer. I mean it, really: like, a borderline-disturbing amount, and it’s all Saaz. Use 2 ounces (57 g) at 60 minutes, 2 ounces (57 g) at 30 minutes, 1 ounce (28 g) at 5 minutes, and 1 ounce (28 g) at flame-out…and maybe even a little 0.5 ounce (14 g) dry hop in the primary fermentor, if you’re feeling crazy. That should give you something in the 40–50 IBU range.
Last, there’s no reason to get cute with the yeast: Wyeast 2001 (Pilsner Urquell) will do quite nicely, if you can get a fresh pitch of it. If not, their 2124 (Bohemian Lager) will do.
You’re also going to need some distilled or reverse osmosis (RO) water.
Process
There’s no way to make this beer (well) and be ignorant of your water chemistry, at least in the broadest strokes. We want soft (but not barren) water. If you’re building up from pure H2O, make sure you have sufficient calcium: the Plzen profile is pretty light on it (about 7 ppm), but you want about 50 ppm to ensure proper conversion! For those who aren’t quite as water-nerdy, if you have “average” water (not especially hard or soft), dilute it by 50 percent with distilled or RO water. If you have hard water (like the fluid rock that comes out of my grandparents’ well), cut it by 75 percent. If you have soft water, leave it be. We’re trying to limit the sulfate/bicarbonate levels in the water (because otherwise the bitterness will come across as grating and harsh), while also ensuring there are sufficient minerals/nutrients for the mash to convert and the yeast to ferment. It’s easier than it sounds, once you get the hang of it, and you can absolutely get there through trial and error if you’re not willing to put in the time, effort, and money to pull a water report and consult the available resources on brewing water chemistry (but you probably should)! (“Brewing Water” can help you along; and if you really want to get serious, check out Craft Beer & Brewing Magazine®’s online course, Brewing Water: A Practical Approach.)
Mash for 90 minutes instead of 60 at 152°F (67°C), then run off/sparge and boil as usual. I’d recommend a dose of Irish moss or kettle finings to help ensure you get a bright, clear beer (floor-malted barley can be slightly under-modified, which can result in haze, though time should clear it all the same!). Ferment at a nice, cool 52°F (11°C) for 7–10 days, and when activity starts to slow, increase the temperature to about 65°F (18°C) to help clean up diacetyl. Many versions retain a touch of buttery flavor in the background, but it isn’t something we should go looking for! After about 14 days in the fermentor, you should be good to go. Crash to help clear the beer further, and then bottle it up and carbonate to a brisk 2.5 volumes of CO2.
In Closing
If the beer tastes/feels too thin or dilute, you might consider an addition of a light toasted malt or CaraPils/Dextrine malt to bulk it up, but I don’t find it to be necessary. In addition, if your bittering is too sharp, you might want to revisit your water treatment rather than adjusting your hops.
I think you’ll find, though, that the ingredients do most of the hard work here, and once you lock this recipe in, you’ll be brewing it regularly!