Svetlé 12°

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Decoction is a meandering path to take to arrive at a beer; you can get a fermentable wort (not the same wort, though) into the boiler with less time and effort, but I think it’s safe to say that for most homebrewers, this whole thing we do is about the journey at least as much as it is the destination.

It’s like espresso, or a tea ceremony – beautiful, but admittedly a pain in the ass to go through for a cup of coffee, a mug of tea, or a krug of beer, and if all we’re ultimately after is a cup of coffee, a mug of tea, or a beer, then what’s the point? I’d say you’re right – but I’d also say it’s a slippery reductionist slope for something as complicated and imbued with tradition and ritual as doppio ristretto, wild Lung Ching leaves, or Pilsner. The effort of preparation and presentation, the mastery over minutiae elevates the whole. It’s still just a coffee, a tea, a beer – but it’s also an experience.

Plus: decoction is very old-school. The reliquaries of old brewing traditions are arguably more on display in the sour, hot-fermented, farmhouse, monastic, raw oat- and spice-laden ales of Belgium, but let’s not forget that decoction mashing lagers is a dinosaur too.

It came about because those cold-fermenting, Alpine cave-cellaring, brown beer-brewing Saxons and Slavs didn’t have thermometers: they could guess closely at body temp and see boiling, but the amylolytic range would have been smack in the middle of thermal terra incognita. But, if we get the mash to blood-warm first, then remove part and boil it, then stir it back in, repeat a few times – boom, wort. Regulating the volume of the boiled portion regulated the temp increases in the main mash once it was added back; add in variations in regional water, local hop varieties, and malt production techniques – boom, classic beer styles.

Someday I’m going to have to explain to my daughter why Flavor Flav wore a clock around his neck all the time (“Because he never knew when Chuck D might need to let all the suckas know what time it was, sweetie”) and it’s going to seem just as arcane and gnostic as some handsomely bearded forefather of our craft sticking his impeccably hygienic Middle Ages finger into the wooden vat to check on how the phytase rest was coming along.

If you can make roux or redeye gravy, then decoction mashing – even a triple, like today’s – isn’t really difficult, just involved – it only asks that you, the brewer, be willing to wander a bit before getting to the boil. It’ll also probably be a longer brew day than you may be used to – this mash took me somewhere around 5 hours from heating strike water to starting the sparge, and I was not wasting time – so remember to budget for that. Tag along on someone else’s brew day before you undertake your own (that’s what I did back in the day) but don’t be afraid to jump in and try it, either – the worst thing you’ll end up with is beer. For the reader who in an earlier thread was lamenting the lack of resources on the how-to of decoction, I’ll reiterate here: New Brewing Lager Beer by Noonan and Bock by Richman are both full of good stuff.

Now, let’s show our work:

Svetlé 12°
Target OG: 1.048


  • 97.5% Weyermann floor-malted Bohemian Pils
  • 2.5% Weyermann Acid Malt (Sauermalz)


Main mash/decoction

  • 95F for 20′
  • Decoction 1: pull 20 qt thick mash* – rest at 148F for half a bagel, 156F for the other half, then boil for 20′ and return to main mash**
  • 126F for 30′
  • Decoction 2: pull 20 qt thick mash – rest at 156F, preheat espresso machine and pull a doppio, then boil for 20′ and return to main mash
  • 147F for 20′
  • Decoction 3: 20 qt thick mash – rest at 156-158F, help dig your neighbor’s stuck front-wheel drive sedan out of the snow in the alley (you can skip this rest if no one is stuck in the snow in your alley), then boil for 20′ and return to main mash
  • 156F for 20′
  • Mashout at 170F for 10′

* For a 10 gallon batch; for decoctions, I pull 1 quart of thick mash per pound of grain in the grist.
** We may not need to return entire volume of decoction to main mash in order to reach the next rest temp – watch the thermometer, YMMV, etc.


  • Czech Saaz (whole, 3.1%aa) at 90′ to 16.5 IBU
  • Czech Saaz (whole, 3.1%aa) at 60′ to 15.5 IBU
  • Czech Saaz (whole, 3.1%aa) at 30′ to 12 IBU


  • Chill wort to 44-45F, O2 and pitch with 2nd-generation Wyeast 2000 Budvar Lager
  • Free rise up to 55F over approx. 36 hours; right now it’s holding around 52 with good krausen and spice/sulfur offgas … and that brings us up to present. Once TG is reached and diacetyl dealt with, it’ll be dump, harvest, rack, crash cool, and see you this summer.

35 thoughts on “Svetlé 12°

  1. Floor-malted! (thumbs up, way up)

    Now let’s build a time-machine so we can have a taste.

    Keep the art alive, MZA

  2. Dawson, you inspired me on your BTV episode to do decoction mashes, now I’ve undertaken a Dunkel Doppelbock and a Doppelbock, the former is lagering, the latter in diacetyl rest. As you said, the greater involvement and touchpoint with the beer made this highly worthwhile. The Doppebock also came in much higher efficiency than the recipe called for, which assumed a single rest at 152. Hey, more beer than expected at the right OG is never a bad deal.

    There are so many incredible Ales brewed by Craft Brewers, it seems that the highly traditional lagers are under represented. Here in Denver, we are lucky to have Prost brewing, which is outstanding, and O’Dell does an unbelievable Imperial Pilsner, but travelling across the nation, lagers are not widely found, which IMO is a little sad.

    If you ever visit DEN again, I would be priviliged to buy you a pint or two. BTV and your incredible informatiion and inspiration are tremendously missed. Thanks for the blog.

  3. So THAT’S why Flav always wore the clock!!! Makes sense. Sometimes suckas do in fact need to be told what’s up. Oh, the decoction stuff was really interesting too. One of these days, hopefully soon, I’m trying that.

  4. Man, since your decoction episode, I’ve been doing small batches as tests for the bigguns. Best one was a pure 100% pilsner malt urquell clone triple lager decoction. 10 freaking hours on a gallon batch and rewards at the end to be proud of. Was waiting for another one of these from you. Thanks.

  5. One sack of Wey FM BoPils on it’s way to my place as I type, I will have to finally jump into decoctions – I have Dawson’s Zweimaschverfahren Dunkel-Kellerbier recipe in BeerSmith to try for my first decoction, and the BTV episode on the Media Center for inspiriation!

  6. Wow, Dawson. That’s a phenomenal post. Once again you’re enticing me with decoction mashing. I really want to try my hand at it, but I’m boiling in plastic buckets with commercial grade kettle elements to lay out the BTUs.

    Damn you, John Blichmann, send me a top tier and some boilermakers!

  7. The Fl. Malted Bo. Pils is “the Can of Whoop Ass” of malts! I’m enjoying a pint of almost exactly the same beer! Kudos on pimping out your beer like a dirty country Czech, always makes beer brewing a soul event.

  8. Any time you can work in Flava Flave in a post, I will read it. I think you should find an old thermometer (a big one) and make a necklace to wear when you brew.

  9. Hey, Dawson. If you don’t mind me picking your brain a little? I have a recipe that includes flaked and malted rye as well as some malted wheat. The brewer who I got the recipe from suggested a 3 step mash which is something that’d be pretty difficult for me to do since I use the orange cooler MLT. I was thinking of mashing in really thick and trying to step up with infusions, and then had the idea that I could do decoctions instead and lend a bit of character and story to my version of the beer.
    With all these adjuncts, is it foolish to even think of decocting the mash? Since I have a lot of huskless grains I’d be adding some rice hulls to the grist, is it a bad idea to decoct rice hulls?
    And I think the final thing that messes me up each time I try decoction is how dry should the thick mash I pull for decoction be? Like should I make absolutely sure I am pulling only grain material and trust that enough water will come out as it heats up or should I grab like a quart or 2 in addition?

    • With all these adjuncts, is it foolish to even think of decocting the mash?

      You’re asking the wrong guy … ; )

      But, multi-temp mash in a cooler – this is where somebody who uses one of those immersible electric elements in their MLT should step forward and preach.

      Since I have a lot of huskless grains I’d be adding some rice hulls to the grist, is it a bad idea to decoct rice hulls?

      I am not sure; I don’t think it would help, though. There’s no reason for the decoctions to not be gloopy and sticky. If it was my brew day, I’d stir them into the mash after the final decoction and before recirc/runoff.

      And I think the final thing that messes me up each time I try decoction is how dry should the thick mash I pull for decoction be?

      Pretty dry … you’ll never be able to get it completely dry, though (or want it to be). I’ve never measured, but for every quart of thick mash I pull there is probably at least a few ounces of liquid. There should be just enough liquid to keep everything in the decoction kettle from burning and scorching instantly. The theory behind all this is that since all the enzymes get washed into solution at dough-in, you don’t want to boil so much of the thin mash that the next step’s conversion is compromised.

  10. Just finished off my sack of the same Weyermann FM BP; waiting on the results lagering in three different 10 gallon vessels from 3 different batches over the last 6 weeks. No decoction, now I wished I had. Gonna’ do my first Belgian Double and will decoct that this weekend – just a five gallon batch (hey, all my 10 gallon fermenters are in use!) – glad you gave the grain weight for decoctions of differing batch sizes. But on the above recipe….what lager yeast are you using?

  11. It seems to me there are far worse ways to spend one’s Saturday than trying to attempt a decoction mash. I’d be game, but I don’t have the means to lager beer. Are there any ales that would work with a decoction mash?

  12. Ja mas rad svetle pivo. After 3 years living in eastern Czech Republic, I love me some traditional brews. Radegast and Staropramen were my fridge staples at the time. A trip back for X-mas in 2011 re-introduced me to St. Bernadus which has a bracing bitterness. Mmm… Inspiration.

  13. My first and only decocted beer was a helles. It tasted pretty good coming out of the carboy. But after being carbonated the dreaded DMS came out of hiding. I’m curious what everyone does just after turning off the flame and beginning to chill. Does anyone cover their kettles right away? Maybe after getting below the DMS range? I brew outdoors and have been afraid of catching some wild yeast. So I’ve always covered up the kettle after flameout. Lesson learned when using 100% pilsner malt. Its a bad idea. I’m thinking of maybe boiling for a full 2 hours next time.

    • I think longer boils help reduce the chance of DMS. As for the open kettle, I have been brewing with my friend in a large 40ish gallon potato boiler (from some military vessel) whiich has a lot of surface area, and we don’t cover it after a boil and haven’t had any problems, so unless you are brewing in a dusty windstorm I’m not sure you should worry too much, but then again I’ve been wrong before.

    • I generally don’t cover post-boil, unless doing a hop stand. Long boils, like Bryan B. said, and also vigorous – simmering won’t help. It’s weird that the DMS in your Helles only manifested after carbonation …

  14. Michael! I’m brewing an identical beer, with 4% Carapils instead of acid malt, to enter in the Pilsner Urquell homebrew competition.

    Any experience with the difference between Weyermann Bohemian or the Floor Malted Bohemian? I can only get my hands on the regular Bohemian without ordering away.

    • I wouldn’t hesitate to use either, or whichever is more easily accessible. The standard BoPils is a great malt; the floor malted version – to me – has a bread-doughier flavor (a bit like wheat malt w/o the phenols or fruitiness) and gives a creamier texture.

  15. “…and it’s going to seem just as arcane and gnostic as some handsomely bearded forefather of our craft…”

    I started growing a beard a few weeks ago, my girlfriend was less than enthusiastic about it at first.

    GF – Why would you want to grow a beard?
    Adam – I dunno, i’ve always wanted a beard. Like a badass brewers beard. Bald head and a solid beard is tough. Michael Dawson tough.
    GF – Who’s Michael Dawson?
    Adam – Shut your mouth and get on the internet, NOW

  16. D,

    I’m a fan of course and one of the many who enjoy the former btv. Not wanting to get into a long blah, but I do hope you and the other fellas know that you made a difference for many of us!

    Ok more straight to the point of questions!

    I’m going to do this recipe and see no issues or questions to ask other than- What exactly is a Svetlé and why did you name this brew Svetlé 12° if you don’t mind my asking?

    I have read some thread on what Svetlé might be but its not as clear as I would like. Sounds like a pre proabition beer, but is this a lager, light lager or pils? I’m also wondering why the use of the acid malt is being applied but I’m actually reading more about that on my own so if that is newbie question don’t worry about it and I will find the answer on my own.

    Thanks for your time, keep on doing your deal here!


    • Hey Curtis,

      Thanks for reading & commenting.

      This recipe is a Bohemian (Czech) Pilsner; in its homeland, traditionally beers were just denominated by color (Svetle = pale, Tmave or Cerne = dark, etc.) and OG – 12 being about 1.048. Since the ideal water for brewing a BoPils is very soft and low in … everything, basically, the acid malt will help drop mash pH without the use of brewing salts. YMMV, depending on your own water.

      • MD,

        Thanks for the quick reply!

        I did the name and your thinking behind it! Thanks also for the info on acid malt = makes sense and a good note to write down for the future! I thought maybe it would add some acid to the taste but it seemed like such a small amount that I really didn’t think that would be much of a factor.

        Another question to you!
        Have you ever made a Berliner Weisse? I have heard about Heretic brewery making a beer called Tartuffe which is described as a Berliner Weisse-style ale. It sounds like a great beer for the summer and I am on the lookout for some summer beers to brew and have for the extra hot 120F days in Arizona that will be here soon. I really was hoping to find an example of the beer to try before brewing it.
        If you have had one, did you like it or would you rather a saison instead? I am a big fan of Saison but have made them threw out the year and thought I’d try something new and not available to be in the area. If you have a recipe or know a source where I could score one I would be very grateful!

        Thanks again, you Rock!


          • yeah ok than I guess this is my request for the future segment! I’ve asked a few people about this beer and not many of them seem to know much about is and from what I have read on-line there’s different ways people go about doing the execution of the mash. So yeah it would be nice to see your example of this brew!

            I’ve heard someone describe it as a cross between a hef and a sour would you agree? I’m not that into banana and clove beers but I’m all about some sourish summer flavors.
            Thanks anyways!

  17. Pingback: TMBR: Svetlé 12° | the beer engine

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