prep day: nerds up, temps down

Czech pilsner: the OG single malt-single hop beer. It’s caramelly, it’s malty, it’s hoppy, it’s a lager but it’s got some yeast character; it’s demanding to brew but it’s so, so easy to drink. It’s been too long since I’ve made one.

Speaking of yeast character: I recently attended the 2013 Rocky Mountain Microbrew Symposium, and on the topic of fermentation byproducts, diacetyl in Czech lagers came up. A presenter posited that Czech lagers didn’t always have diacetyl as an accepted stylistic component – it was, according to the presenter, when Pilsner Urquell shortened their lagering regimen from approximately 3 months at 33.5F to approximately 1 month at 33.5F (times are from the speaker’s presentation, and I got the temp from Jackson’s Beer Companion 2nd Ed., in which he says “the beer is said to be lagered for two to three months,” but this was in 1993 at the latest, so …). The upshot being that at that temp, there was no way the cells could reabsorb all of their nasty little vicinal diketone leavings in that short of a time, so the flavor threshold was crossed by the paragon of the genre, and at some subsequent point diacetyl was written into the style description. It’s been a long old time since I’ve done an analytical side-by-side, but I seem to remember differing levels of diacetyl from brand to brand in the Czech imports. Discuss.

A different talk at the RMMS dealt with craft lager brewing in general, but diacetyl came up again here. The regimen used by the presenter’s brewery was designed to produce a clean lager with quick turnaround – at a comparatively elevated primary temp range of roughly 50 to 55F (vs. the 42-43F cited by Jackson for Pilsner Urquell), vicinal diketones are produced and reduced quickly.

The wort is knocked out and inoculated at a temp that’s a good several degrees colder than the target fermentation range – since esters and other compounds undesirable in a lager are produced in the first 24-48 or so hours of fermentation, the cold start helps suppress their formation. The ferm temp is then allowed to rise into the low to mid 50s once the wort is at about 50-60% attenuation; this makes sure that both diacetyl reduction and attenuation complete in a timely fashion and – I think this is cool – obviates the need to slowly ratchet the temp down to lagering after the yeast is cropped – since its work is already done, you can just crash it straight down to 32-34F or what have you. Assuming you’re starting at 55F, this alone could shave weeks off a traditional lager fermentation schedule. Maturation time is also shortened, with the speaker citing standard-gravity lagers that can be ready for packaging in as little as 3 weeks (obviously this is highly dependent on the yeast strain and other factors).

Over the years, I have gravitated towards a pretty similar schedule for all my lagers that are not fermented with a sulfury fart-bomb yeast strain (I love you, but I’m looking at you, 2308 and 2042) with positive results, but it’s nice to have it validated by a dude in a brewery workshirt with Powerpoint cred. Discuss.

Anyway: new crop year whole Saaz (natch), 2nd generation Budvar yeast (washed), Moravian 2-row barley malted on the finest floors. And that’s pretty much it. I love how stripped-down and elemental this style is, and how the whole ends up being a good deal greater than the sum of its parts: fermentation really is magic.

But before the magic happens, I gotta dose out hops, weigh out the grist, actually harvest and wash the damn yeast, mix up some new sanitizer, check the propane supply, check the coffee supply, check the O2 supply, futz with a sticky QD, print out the brew sheet … I’m exhausted, and I haven’t even done the first decoction. Better get more coffee.

Brew day write up and recipe forthcoming. Nerds up, temps down.

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31 thoughts on “prep day: nerds up, temps down

  1. I’ve tend toward 49F for primary pitching temp and leave it for a month then cold crash, then rack and keg after a couple days. Lager near freezing for 2 weeks on carb and serve anytime after tat. Seems to work for most yeasts I use (currently a rotation of WLP 800 and 34/70 repitching for the umpteenth something time).

    Cheers for those lagers – smooth and crisp.

  2. The procedure for higher primary temps will be the procedure I try for my next round of lagers. I currently have a Rothaus Pils clone and a Maibock at diaceytl rest temps right now after fermenting down to 1.020. I wanted to make a Kellerbier for my next round and needed something else to try, so I think you Czech recipe, along with primary temps you outlined above, might be the one. BTW, have a good Kellerbier recipe? :)

    So, I am fairly new to lager brewing and have a question that I can’t seem to find the answer to. I ferment in corny kegs (the fridge fits 2 equaling 8-9 gallons vs. 5 gallons from 1 carboy) and am nearing the end of my diaceytl rest. When I transfer, how much yeast do I want to go with? Just what is in supspension? I will be transfering to another keg with CO2 for lagering and serving and left these dip tubes stock so I can pump out whatever yeast/nasties settle out during lagering.

    Thanks for the help and great post!!!

    • Re: Kellerbier recipe – sorta. My take is that “kellerbier” is more of a process that can be applied to different beers than a style unto itself – like “cask ale.” Kellerbiers are basically an unfiltered lager packaged young and served at a low-ish level of carbonation, which is pretty straightforward for a homebrewer to do … my experience has been that the choice of yeast is key, so that you get something drinkable and not overly yeasty at a tender age; I’ve personally had the best luck with the Ayinger strain (Wyeast 2487 or WLP833). In Bavaria, this usually meant a Helles, but we also had keller versions of Munich dunkel and Rauchbiers of various shades, so as far as a Kellerbier recipe I just take a standard formulation for one of these styles and keg it right out of primary (making sure to dot i’s and cross t’s for diacetyl rest and all that jazz). I have never tried a keller version of Czech pils, so I can’t say how those yeast strains or the higher hop levels of those beers vs. the Bavarian styles would play.

      Re: yeast separation at racking – sorta. Generally whatever’s in suspension is fine to carry over, but this is pretty subjective and experience is going to be your best teacher. Ideally, assuming all the VDKs are reduced and the beer is at terminal gravity, you’d leave all the yeast behind since it’s not really needed anymore. If the beer’s not totally clean you’ll still want a bit for reduction and conditioning. But if you’re using a really powdery strain like 2042 or 2124, I’ve found a good deal of settling in the secondary is inevitable. Hope this helps!

      • Thanks for the reply.

        Whenever my fiancé goes to the drink store (I don’t know the translation for Getränkemarkt), she always picks me up some random beers. Last night I had a Fürst Wallerstein Zwickel and it was awesome. Light brown bordering red color and just delicious. Raisin/plum with slight maltiness. Maybe I will have her get some more and try to harvest the yeast from the bottle. I will give the Ayinger strain a shot.

        Thanks for the info on the yeast. I am using 2124 on one of them and will make sure to let that settle. I plan to ratchet down the temp about 5 degrees a day to reach lagering temps. Once I hit that, I will transfer to my lagering vessels and commence lagering.

        I look forward to the Czech Pils recipe.

        Also picked up 10oz of Mosaic based on your post and I am excited to try them.

  3. I just started reading Greg Noonan’s(the creator of the Black IPA) book New Brewing Lager Beer,and was thinking about trying out his Maibock recipe. Great book by the way. Love the Blog keep it coming.Cheers!

  4. All else being equivalent, it would be interesting to compare diacetyl levels in both decocted and nondecocted beers. When properly executed, decoction mashes produce a pool of reductones. Unless these reductones are metabolized by the yeast during primary fermentation, I imagine they probably are capable of reducing, at least in part, offending VDKs to the corresponding alpha-hydroxy ketones (i.e. “acetoins”) and vicinal dialcohols. Likewise, brewers often employ a protein rest during a typical decoction mash. I imagine this step enriches the wort in the vital amino acid valine. The presence of valine in the wort represses formation of diacetyl (Fix). What I gathered from your post, MD, is the problematic strain-to-strain variance in diacetyl readsorption by yeast (i.e. temperature dependence of this process). So, this begs a couple of questions: 1) Do brewers really need to rely on yeast-mediated diacetyl reductions? 2) Could brewers enrich the wort in other naturally occurring reducing agents (e.g. NADH/H+ or other flavanoids) that would chemically reduce diacetyl in the finished beer?

    • Great points, DK.

      Obviously an ounce of prevention is better than a pound of cure, right? Suppressing VDKs through strain selection, wort composition, and/or fermentation management would make life easier. I think a couple factors still support relying on yeast cell reuptake (and I say this as a parent: little buggers should clean up their own messes):

      1. I think it’s safe to assume that the majority of lagers aren’t decoction mashed anymore, commercially or in basements (and least some don’t get a protein rest either). It’s pretty understood that modern malting and all the protein degradation that happens upstream of the brewhouse has made decoction mashing more of an aesthetic or tradition-maintaining decision these days … and if I understand you correctly, that means that the generation of all those non-yeast reductones and reducing agents would go way down, right?

      2. From a brutally bean-countery efficiency perspective, it’s cheaper and easier (commercially and in basements) to just let the temp on a ferm tank creep up for a few days than it is to decoct.

      It’d be interesting, from an apples-to-oranges perspective at least, to pitch a known diacetyl-prone ale strain into a wort like the one you describe and see what happens.

      • “It’d be interesting, from an apples-to-oranges perspective at least, to pitch a known diacetyl-prone ale strain into a wort like the one you describe and see what happens.” Agreed. Perhaps I could persuade my club to help carry out the requisite “scientigious” experiements.

  5. Love the Lager speak as my passion these days are local “Winter Bocks”. Take and put down your Paulaner Salvator Dopplebock for half a second – hard to do I know – pick up a Michigan brewed Frankenmuth WinterBock – wow! – and no transcontinental import MotherEarth tax on the Fankenmuth brew from just up the road (from me anyway). Those Germans up in fake Bavaria know just what the heck they’re doing for sure.

    Lager away Meister Blogger – I do enjoy!

  6. On the subject of decoction mashing…I’ve done it once with a Weizenbock with too small of a mash tun and it turned into a sticky mess of a mash, but the final product was great. Despite the mess I’d do it again for sure. There isn’t so much info around about decoction dos and don’ts. Decocting for lagers only? A waste of time for ales? I’ve got a Belgian Wit in the queue and was thinking about decoction mashing that, and since you brought it up no better time to ask somebody who knows way more than me. Mash on.

    • Next time you’ll probably have a more fun time decocting an all-barley beer … wheat gets gummy all by itself in an infusion mash. Not to say one shouldn’t decoction mash a Hefeweizen or Weizenbock … those are ales, after all. So are Dusseldorf Alts, which can also be decocted.

      For something like an English brown or US Pale ale, the main argument against decoction, I think, is that in an English/Belgian/domestic “pale ale” malt, whether it be Maris Otter, Golden Promise, etc., the enzymes that are actually doing something at the lower-temp rests of a decoction schedule have already been denatured in the malting process … glucans are already reduced, protein profile is already fixed, it’s not going to enhance sugar formation and extraction, so my understanding is that we’d just be staring at more or less inert grist waiting to come up to a sacch’ temp. Having said that, first – it seems conceivable that the Maillard reactions and melanoidin formation of the decoct could have an effect; and second, I’ve never tried it myself.

      Witbier might not be a great candidate for decoction, what with all the wheat and raw oats – plus, you want to keep that guy pale-colored. IIRC, there’s a nicely laid-out traditional Leuven mash schedule in Brewing With Wheat that uses a lot of low-temp rests, but it’s a step mash with infusions. Hope this helps!

      • Decocting a witbier would be kinda like conducting a traditional turbid mash. My limited experiences with mash programmae and schedulae have shown that quick transitions between temperatures and limited “sitting” time yields best results, whether removing a chunk of grist or adding heat directly.

  7. Great post Mr. Dawson, this tickled both my nerdy bone and my funny bone! Will have to try this fermentation/lagering schedule on my next Pilsener. Good replies from the group as well. Brew strong everybody!

  8. I’m suspicious of the claim that diacetyl that wasn’t cleaned up after a month at 33.5F would be cleaned up after two months at 33.5F. From everything I’ve ever read (and experienced) diacetyl reduction should be completed before the beer reaches near-freezing temperatures. Even a hardy lager yeast isn’t going to be doing much at such a low temperature.

    • FWIW, that’s been my experience as well, and I’ve also found VDK/diacetyl production in lager yeast to be fairly strain-dependent. My experience has also been that lager yeast will keep working at sub-primary temps (eg, gravity drops a couple points in secondary) albeit very slowly.

      In the same book (which, granted, is now 20 years old) where I gleaned the 33.5F lagering temp, Jackson says the fermenting areas at PU are (were?) held at 39-42.5F … even allowing for heat generated by fermentation, that’s still a chilly primary; so the 2 month-vs.-1 month claim in conjunction with a low, non-conducive-to-VDK-reduction fermenting temp – and assuming no rise at the end for a diacetyl rest – seems at least somewhat plausible.

      Thanks for reading, thanks for the comment! Now I really want to do some side-by-side Czech lager tasting …

  9. Love the blog MZA, you have so much knowledge on this stuff it’s unbelievable…

    So I have read your post a few times, and I’m not sure I completely get the lager schedule. I’m sure it is because I have never actually done a lager. I’ve read a lot about it, but I’ve never actually done it. I think I need to close the laptop lid and just try one..:)

    Here is what I am interpreting from what you wrote. Can you correct me where I went wrong?
    Chill wort down to 46 F and pitch yeast, is that the right temp? I’m referring from braukaiser has 46-50, but you say slightly cooler than recommended temp, is that recommended from wyeast?
    Hold temp at 46F to get to 50-60% attenuated, about 7-10 days?
    Let the temperature slowly work up to 52-55F (how long should this take) I hear people say let it rise naturally, but I would think that has everything to do with ambient temperature and how much insulation you have in your freezer. How long should it stay at 55F? Any measurements done during this time, or just a time thing?
    Crash to 32F for X weeks

    • Chill wort down to 46 F and pitch yeast, is that the right temp?

      IMO, this is a horseshoes and hand grenades kind of target. I usually aim for somewhere in the mid-40s, but you can tailor it to the preferences of whatever strain you’re using.

      Hold temp at 46F to get to 50-60% attenuated, about 7-10 days? Let the temperature slowly work up to 52-55F (how long should this take)

      Personally, I don’t hold it at the pitching temp … timing depends on pitch rate, yeast health, O2, wort gravity and all that, but I am usually pretty close to TG after about a week, so 50-60% attenuation could be reached as soon as day 3 or so. In my basement at this time of year, I usually just let it free rise and it reaches that low 50s range after 3-4 days.

      How long should it stay at 55F? Any measurements done during this time, or just a time thing?

      Until TG is hit and diacetyl is below threshold; then you can separate the yeast and break material and crash it to lager temps until it’s time to package.

      • Thanks for the reply! You make lagers sounds so easy.. :) Maybe I am over thinking this…

        So what is the ambient temp in your basement? About 55-60? What I am struggling with, is that I am using a temp controlled freezer in my garage (in Milwaukee) so the ambient temp is right around freezing usually. When I do an ale, I put the thermocouple right on the side of the carboy and heat or cool to keep the temp of the carboy stable. Would I instead just hold the free air temp at 55, and then it will rise up based how much thermal mass, etc is in the carboy. The other option is I put the thermocouple on the carboy and then change the temp up a degree each day to control that ramp..

        • Right now it’s about 56-58, and if the weather holds and history is a good indicator, it’ll stay under 60 through March. Push comes to shove, use 2124 or the equivalent, since it’s pretty tolerant of abnormally warm (for a lager) temps.

  10. Really looking forward to seeing how this one turns out. I’ve got to say, I’ve never had the balls to do a proper single malt pils, and I just don’t have the facility to decoction mash in any significant volume.

    I boil in plastic buckets into which I fitted kettle elements….

    Someday, I’m going to get the full top tier package with a bunch of 10 gallon blichmann pots. Someday.

    Over the beery rainbow.

  11. Being that it’s March 1, I was just planning out a Marzen this morning and this post seems super timely. I just want to make sure I’ve wrapped my head around what’s been said here and summarize all the other tips I’ve gleaned to reduce/eliminate diacetyl.

    *Protein rests can help and decoction might help, although modern malting techniques reduce the usefulness of this.

    *Be super vigilant about sanitation. Bacteria can boost diacetyl.

    *Chill your wort to mid 40′s. Make sure it has plenty of available nutrients and oxygen.

    *Pitch a big healthy starter. Steer clear of known troubled strains.

    *Fermentation for the first 50/60% of the way should be done in the 40′s, then letting it rise to the mid 50′s for the final push. Ferment under pressure if possible.

    *Rack off primary before chilling to lowish 30′s for lagering. Do whatever possible to reduce aeration during transfer.

    *Krausening for carbonation will help as opposed to traditional priming sugar.

    *If all else fails, beg/borrow/steal some MatureX L from a brewery and pitch with your starter. Problem solved!

    Do I have that all right? Am I missing anything that I might use to get me to a 3-4 week fermentation schedule? Thanks!

    • With the caveats that: this list introduces some variables not covered in the RMMS talk or the original post; and that this regimen isn’t a magic bullet for a 4-week lager (allowances always have to be made for OG, right? A Marzen or Bock is a different beast than a Pils or Helles), I think that looks pretty good. That “overcooling the wort into the 40s” bit is a pitching temp, not necessarily the ferm temp … as mentioned further up in the thread, my own process is to, after pitching, let it rise on its own up into the basement of the strain’s preferred range – YMMV. Good luck!

  12. I decided to do my first pilsner a few weeks ago after watching the brewing tv episode that uses lager strains close to ale temps. I rely on ambient temps so I’m currently lathering at about 55 degrees. Pretty warm but I definitely decidd it wasn’t the end of the world to ferment there.

    • While I prefer cooler temps, I have heard of competition lagers winning awards at higher range temperatures, so MD’s regimen of allowing the rise to occur after half way or greater in primary seems sound. YMMV and I go on the cooler side because my chest freezer holds 2 ten gallon batches at a time and I want the non fermenting one to be at a relatively cool temp while I allow it to be cleaned up and preliminarily lagered. So, my arrangement is based on my limitations of equipment – if I were doing smaller batches and had natural or additional chilled space to do it differently, I likely would.

      Sorry for the long post – I would love to see shorter turn around times so keep the info coming.

  13. Great stuff. Great blog. Beer geek heaven is here, at least the Minnesota sector! I’m managing one or two lagers a year when Minnesota temps get low enough in my basement too. I hate the sulphur farts from the fermenter when I use 2001, but I _love_ the taste of the beer! My 2c from frequent Eastern Europe trips is that supranational breweries, regionals, and locals there go for more diacetyl in their Pils than the Germans, esp. Northern Germans who want that beer dry, dry, dry!. Sorry to say, but Pilsner Urquell has changed in the last years and lost some of the fine smooth mouth feel. Zywiec still holds it well; at least to my uninitiated non-BJCP taste sensitivities.

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  15. Hey Dawson,

    I’ve harvested yeast before but never got around to using it since I didn’t have a great brewing schedule. I’ve started brewing much more often and also doing 10 gallon batches so harvesting yeast now is becoming a necessity to save $. How long can you typically save yeast after washing it before making a starter again? I have 10 gallons of helles bubbling slowly on day 10 and soon will come the D-rest and transfer to secondary for the ramp down and long lagering period. I’m using two different yeasts and plan wash them both for future use.

    • Hey mattybrass,

      The directly-repitchable lifespan of a washed slurry is measured in days; maybe up to a couple weeks. Past that, viability will drop off pretty fast due to the high cell density, and best practice would be to reculture it before pitching into a new batch. When I harvest and reuse yeast, I try to knock out a series of batches in quick succession, all using successive generations of that strain. Hope this helps!

      • It does thanks! I typically harvest (4) 8oz mason jars from each slurry which ill probably end up keeping 2 and sharing 2. I would definitely decant and make a starter prior to pitching for them.

        Unrelated I work for my LHBS and wanted to ask you some wyeast questions. What’s the easiest way to contact you via wyeast?

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