brew day: Cerny 13°

Between propagation and family get-togethers, this batch has been a long time coming. I enjoyed the numbered digressions so much last time, I’m going to indulge in it again. Sorry.

1.The yeast – the Old One, the dead one that lay dreaming, now awakened and hungering – that I have been propping up is 2782 Staro Prague Lager, the ne plus ultra, the once and future king, the undisputed heavyweight champion, scientifically proven to be the greatest Czech lager strain of all time.*

* citation needed

2. A (relatively) quick n dirty single decoction for a weeknight brew session after the last item on the winter holiday social calendar. <soapbox> I’ve seen it stated that decoction mashing is – probably in general, but specifically for homebrewers – unnecessary and a waste of time. I can’t argue that it’s unnecessary; there’s certainly no need for it in order to achieve conversion with the malts we have to work with.

“A waste of time,” though, gets my hackles up a bit: a pastime that is, for the vast majority of the 1.2 million of us, first and foremost a recreational, creative, and relaxing (as opposed to competitive or vocational) pursuit shouldn’t have stipulations of “correctness” or efficiency imposed on it. Maybe you’ve heard the same thing about something else, like not brewing all grain. Or fly fishing for trout with anything but dry flies (which would in truth be lame, but I digress even further).

Last week, a mutual friend sent me a newspaper article on homebrewing from the year 1998. Besides a number of interesting parallels between then and now, it contained a positively zinging quote, which I’ll try to paraphrase: “A homebrewer is someone who will spend 10 hours trying to figure out how to make something he can buy for $5.00.”

That is a truism, citizens, and the umbrage I take with the “waste of time” argument – besides the fact that it’s my time; and besides the fact that it overlooks the actual reasons that so very many of us homebrew in the first place, or at all; and besides the fact that it ignores the intangible (but I would think still obvious!) payoff we get beyond the self-evident pints and attendant need to piss – is that, extending that logic to its conclusion, the production of beer at home by amateurs is a waste of time. Seriously. The pros can do it better, easier, and cheaper, so what are we doing boiling grain or stirring in malt syrup and having fun?


3. Czech dark lager: yes, please. Bohemian spring barley, Saaz-intensive, a bit more bitter and with a bit more hop flavor than Munich Dunkel. I only wish I had it ready to drink right now, because it would take the edge right off the wind chill.

Cerny 13°
Target OG: 1.052


  • 89% Weyermann floor-malted Bohemian Dark
  • 6% Weyermann Caramunich II
  • 4% Weyermann Carafa II
  • 1% Weyermann CaraAroma


Main mash/decoction

  • 135°F for 30′
  • Decoction 1: pull 10 qt thick mash* – rest at 148F for half a game of fetch, 156F for the other half, then boil for 20′ and return to main mash**
  • 158°F for 20′
  • Mashout at 170°F for 10′

* 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.


  • Saaz (whole, 2% aa) at FWH to 20 IBU
  • Saaz (whole, 2% aa) at 30′ to 7 IBU
  • Saaz (whole, 2% aa) at 15′ to 1 IBU


  • Chill to 45F, O2 and pitch with Wyeast 2782 Staro Prague
  • Free rise up to 56-57F over approx. 48 hours.
  • Once we hit TG and diacetyl-negative: fine, rack, crash cool and lager. Like you do.

40 thoughts on “brew day: Cerny 13°

  1. I fully agree with your reasoning, Mike, that it absolutely is not a waste of time. This is a hobby, and the hobbyist is free to spend his time however he pleases. Time spent practicing a hobby is not wasted. That said, I also submit that there is more to be gained from decoction than the intangibles of enjoying that the journey is the destination; certain beers brewed with modern well-modified malts are better if they were decocted, all other things being equal. You can make a very good Munich Helles or German Pilsner or French Saison with a single infusion mash. But to make a great one with a large portion of je ne sais quoi, you need to boil that thick mash.

  2. It seems to me that the people who say “why bother when you can buy it” don’t really have an understanding of what you can do with the hobby. There are many of my brews that I simply cannot find a good facsimile for in the local beer mart. Not to say it doesn’t exist somewhere, but I certainly would not have access to it otherwise. And that leaves out the whole bit about me actually enjoying the hobby as time well spent, no matter how much time it takes.

    I’d be willing to bet there are many things that the author does him or herself that they could “just buy.” Many of those things are probably something they would like down upon others for not being able to do, such as making themselves a decent meal or fixing little things around the house. Money can buy just about everything except the satisfaction of a job well done and the joy of the craft.

    – Dennis, Life Fermented blog

    • That is a great question. The short, not-intended-to-be-snarky answer is “as soon as it’s ready to package and/or drink,” but how long that actually takes depends a lot on yeast, beer style, the rest of the process, and the brewer’s intention. A traditionalist might say lagering takes 7 days (or so) for every 2 degrees Plato of OG; a more intuitive approach might rely more on sensory analysis (e.g., beer clarity and byproduct levels) than a firm timetable. A pale lager for short-term consumption could get put through the steps quickly, while styles with some degree of seasonal or ceremonial association like a Marzen or Doppelbock might get lagered for months regardless.

      • Not to mention the temperature of the beer during Lagering plays a role in how long you need. Charlie Bamforth says, paraphrasing, that two days at 28F is better than two weeks at 38F. For the homebrewer, the answer I think is judicious note taking across many delicious batches. The problem I have with every batch is that I move the keg from the lager fridge to the 40f keezer when I think it’s ready after a few weeks, only to find the last glasses drawn from the faucet 6-8 weeks later are much better than when the beer was (now obviously) tapped too early.

        • Sure – Plato is just a different scale to measure wort density/specific gravity; it’s more common in Europe, hence the use with that lagering timetable. 1 Plato is roughly .004 on the SG scale, so an OG of 1.040 on the SG scale would be about 10 Plato.

  3. Curious – how do you accomplish your free-rise? I have my temperature probe taped to the side of my fermentation bucket normally, and I have both heat and cooling capabilities in my fermentation chamber (fridge in my garage with a hair dryer). If I were to try something similar, what would you recommend?

  4. Waste of time? What about a waste of life until I learned to homebrew!!! My wife loves that I’m in the garage and not on the golf course. Fully sanctioned by SWMBO – what could be a better hobby/lifestyle/obsession?

  5. For me, “lagering” seems to be a case of bizarre semantics. Camp A implies an active secondary fermentation, sans finings and careful negative temperature ramping. On the other hand, Camp B says “lager” when they are simply “cold conditioning” to drop the beer bright.

    I think that I read somewhere (I think it was on 20acrecarcass) that “hobbies are important.” Couldn’t agree with that sentiment more.

    • True – and it’s not really helped by the relative imprecision of the term in German (“to store”). I will cop to mainly being after clarity, and a purist would point their finger at me and call me a cold conditioner.

      • I’ve ordered my first lager kit (Bavarian Helles) and I have a few questions. The lager strain is Wyeast’s 2308 Munich Lager, do you have familiarity working with this strain? It seems the style I’m brewing doesn’t show up on Wyeast’s site and all I can get out of people is “Be sure to do a diacetyl rest!” Also there is an option to do a single infusion or a step mash involving multiple rests. I don’t have a direct fire tun so this would require lots of math and thermodynamics charts. I’m assuming the grist is mostly pils malt but I can’t be certain, how important would a step mash be to this recipe? Any light you could help to shine would be much appreciated Dawson.

        • Hey Patrick,

          Re: Munich Lager – yes, I have used it many times, it’s a great one for Helles and will taste very true to style. I think the diacetyl rest (basically a rise in temp at the end of primary – 2-3 days at 58-60F or so) is a very good piece of advice, and I would definitely make a large starter (or step it up a couple times). Its offgas will likely be very sulfury during primary, so don’t be alarmed – that aroma will condition out (and a diacetyl rest will help expel it as well).

          Re: mash schedule – since a great lager can be made with a single-temp infusion and since this is your first lager, my advice would be to focus more on the fermentation than the mash; that will have a bigger impact on the outcome. Good luck, let us know how it goes!

          • Thank you Dawson, I took your sage advice to heart and the Helles is in the keg and tasting mighty fine! My new question for you is what recipe should I attack next with the next generation?

    • Sure, but it’s still highly dependent on process and technique … a lager kept in a full or purged vessel and which avoided O2 pickup during transfer, bottling, etc., wouldn’t be at any greater risk of oxidation during storage than any other beer.

  6. “…besides the fact that it’s my time; and besides the fact that it overlooks the actual reasons that so very many of us homebrew in the first place, or at all; and besides the fact that it ignores the intangible (but I would think still obvious!) payoff we get beyond the self-evident pints and attendant need to piss…”

    You go girl!

  7. First and foremost, there is absolutely nothing wrong, lame, or unfulfilling with fly fishing for trout using a Wooly Bugger or Bunny-strip leech. Mainly because those are the only two freshwater flies my fat fingers can tie. And to your point, tying your own flies is like the decoction mash of fishing. Sure, it’s not really necessary. But it definitely make the whole process more fulfilling to me.

    Secondly, I’ve never seen the Bohemian Dark malt before. NB lists it as 5-8 Lov. How does this compare to Munich? Or is it closer to Vienna?

  8. Am I really terrible when I say I lager old school style with out temp controls?
    I have a unheated portion of my house that is below freezing with the current single arctic blast we share MD as well as the twin cities area. I brew, pitch my yeast and throw it in the unheated area. When the temp is below 40 I throw a grow mat under the carboy and let it sit for a month, rack to the secondary for a month or two depending on what the brew is then bottle. It varies a bit but damn if its not drinkable, requires a 20 dollar investment that I can use to grow veggies in a month or two if needed and is “traditional.”

  9. Another great episode!

    And I share your affinity for decoction mashes. I tried it when I brewed up an oud bruin, and have done several more since then. All of those have been BIAB and multi-decoctions. I did BIAB because it was the best way for me to deal with actual grain on a full-time grad student budget. I did the decoction mashes because it sounded fun.

    I just acquired some more traditional all-grain homebrewing equipment, thanks to some generous family members. I bet I’ll find all kinds of inefficient ways of having fun with it.

  10. First let me say that I really enjoyed this post. I myself, find it important to be fluent in the traditions of the activity of which we love. As a music teacher, I see the same attitude. I have to explain that without Bach there would not be rock and roll. Keeping with and learning the traditions of any activity is always important! – End my soap box. Thanks for listening.

    Now on to my question about decoctions. I’m doing a Pilsner Urquell clone (5 gal batch). I’m planning on doing a triple decoction. I did one last year with a double decoction. Basically, I’m trying to brew it as close as I can to the way the brewery in Pilsen. According to the article on Morebeer’s website, it says the brewery uses a mash thickness of 1.85 L/kg. If my math is correct that’s around .89 qts/lb. Other places where I’ve researched decoction mashing recommend 1.75-2 qts/lb. What mash thickness do you use?

    • Cheers!

      With the understanding that everybody’s process and system may be a bit different: I use more towards that 2 qt/lb ratio for the main mash in a decoction regimen (the decoctions themselves will be much thicker). A ratio of 0.89 qt/lb for the main mash would be way too thick for my setup and process. My unsolicited advice would be if last year’s double decoction went well and the equipment is the same, use the same ratio for this batch.

  11. Pingback: brew day: Cerny 13° | Fellowship of the Brew

  12. The little I understand decoction mashing, it serves (at least) two purposes: To create “darker” flavors through Mallard reactions and caramelization and to help raise the temperature of the mash for multi step mashes.

    Now if one has the capability to directly heat the mash (like I can in my BIAB setup) one could “deconstruct” a triple decoction mash schedule into a multi step mash by directly heating the mashtun and do a single decoction boiling for creating the Mallard flavors, or what?

    • With the understanding that it wouldn’t 100% mimic the effects a multi-decoction process (not that it has to; but changing the volume, duration, etc. would alter the effects of those reactions on flavor & color), I think that would still be a valid approach and yield tasty, tasty beer. If you try it, please let us know how it goes!

  13. Pingback: tasting notes: Cerny 13 | the beer engine

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