The Pilsner Urquell showdown: Decoction Day

By not brewing this beer when I first posted my original article, I think I psyched myself out on the whole ‘decoction’ thing. “Single Decoction“, “Double Decoction“, “Enhanced Double Decoction“,”Hochkurz Decoction“, “Triple Decoction“, ahh!!! What have I got myself into!!

When I finally got up the courage and picked a weekend for this experiment, I had to watch and re-watch some videos on decoction mashing. Braukaiser’s video, which I had mentioned in my original post, was one I referred to a lot. I also came across a really good video on Brewing TV: Episode 34 – “Decoction Day”. In this video, Michael Dawson shows us how to do a double decoction on a Munich Dunkel. He was quite entertaining and demonstrated the steps wonderfully and clearly. So off I was to start boiling away!

Which decoction schedule did I decide to use? I decided to go with the Enhanced Double Decoction. This schedule pulls a large enough decoction from the acid rest to be able to hit the protein rest with part of the decoction, and with the remaining portion, you reach the saccrification rest. On the one side, I thought a single decoction would fail to bring out enough of the decoction character. On the other side, a traditional triple decoction really isn’t needed with today’s well modified malts, and the lengthy protein rest can actually be detrimental to head formation and mouth feel due to excessive protein breakdown. (See footnote at bottom) I modified the temperature steps slightly to hit those specified by the brewer from Pilsner Urquell in the Brewing Techniques article: The History and Brewing Methods of Pilsner Urquell.

  • Acid Rest: 95°F
  • Protein Rest: 127°F
  • Saccrification Rest: 143°F
  • Mashout: 163°F

Enhanced Double Decoction:


When decoction day came, I still wasn’t 100% sure exactly how much decoction to pull, because Beersmith gives me one set of numbers, Braukaiser another, and Brewing TV, another. In the end, I went with Braukaiser’s formula since I was referring to his video the most, and following his enhanced double decoction schedule anyways.

I mashed in at the acid rest and measured my pH after a couple minutes. It was higher than I expected at 5.8. (On the single infusion batch, I measured a pH of 5.56) I left it for 40 mins to see if it would lower, but it didn’t seem to. Trying not to mess with it, I just went ahead and pulled the first decoction. Using Braukaiser’s formula, I calculated a decoction of 2.25 gallons of thick mash. It ended up being most of the grain, with some liquid added in to make up the rest. I brought it up to a protein rest of 127°F for 10mins, then up to 152°F for 20mins, checked for conversion with an iodine test, then proceeded to bring it up to a boil. All the while, I was doing this quite slowly, perhaps a couple degrees every few minutes. It was interesting to see the viscosity of the mash change as I went through the different temperature ranges. I made good use of my new wooden mash paddle as you need to constantly stir the decoction so the grains don’t scorch on the bottom. I boiled it for 10 mins and then proceeded to add a quart at a time back to the main mash until I reached the protein rest at 127°F. Letting it rest there for 10 mins, I continued to boil the remaining part of the decoction. It’s always said that it is better to pull more decoction than less, as you can always let any excess cool down before you add it back. Of course, when I tried to add the rest of the decoction back to the main mash to reach the next step at 143°F, it was clear that I didn’t pull enough. I was a little short at 138°F, so what I did was transfer the main mash to my brew kettle in order to heat it up the last few degrees.

Now I had my doubts about this temperature step, because it is very low for a saccrification rest, but who am I to argue with the masters at Pilsner Urquell? I got it to 143°F, but then wasn’t sure how long to leave it, so I decided upon 1 hour. I then checked it for conversion = nothing. Still tons of starches in there. I waited another 30 mins = still nothing. Another 30 mins, still not much. Then I thought, maybe the 143°F rest is a maltose rest like in the Hochkurz Double Decoction, and I still need to bump it up to the dextrinization rest at 158°F to get full conversion? (or the 163°F as mentioned by Pilsner Urquell) Maybe I had interpreted the numbers wrong? (I’ll have to research and see if there is something I don’t yet understand in these steps.) So that’s what I did, I bumped it up to 163°F, and in 20 mins, it was all converted. So as luck would have it, it was perfect that I had transferred the mash to my kettle because I was able to heat things up when necessary!

It was already obvious that this was going to be a long brew day, but I finally pulled the last decoction, this time using the amount that was calculated by Beersmith. I again slowly heated it up, but this time without any prolonged rests, as most of the starches were converted at this point anyways. I boiled it for 10 mins and then returned it in portions back to the main mash. This time I hit my mashout temp exactly at 168°F. Woohoo! At least something went smooth!

So after 11.5 hrs of brewing, I had finally finished my first Decoction brew. I can already tell you that the wort is darker and richer than the single infusion version. It smells absolutely heavenly, a lot like the real Pilsner Urquell. I won’t count my chickens just yet, but so far, so good. The real test will be in the taste.

To be continued…


FOOTNOTE: A few of you have expressed that there isn’t the need for a protein rest given today’s well-modified malts, which is true. The enhanced double decoction takes this into account and instead uses only a very short protein rest of about 10mins at the higher end of the spectrum to encourage medium chain proteins which are good for head retention and mouth feel. Referring to Braukaiser’s page for some insight into this, he says:

The mash schedule shown above is well suited for European
and continental lager malts. Aim for a protein rest
between 129 - 133 °F. This temperature puts emphasis
on the protein degrading enzymes that produce the medium
chained proteins which are good for head retention and
mouth feel. The well-modified modern malts already have
enough short proteins (amino acids) and a rest closer
to 122°F is not necessary.

NOTE: If you want, you can actually skip the protein rest altogether and go straight from the acid rest to the saccharification rest.


7 Responses to The Pilsner Urquell showdown: Decoction Day

  1. Good for you… even though I’ve read a lot about decoction mashing, it still really overwhelms me… and scares me a little! I don’t think I’m quite ready for a 11.5 hour brew day yet… maybe when things settle down a bit at home!

    • haha, yeah, you have your hands full I’m sure.
      Honestly, it’s not as scary as it sounds. I could literally shave off 2.5 hrs next time, just because I’ll have a better idea of what I’m doing. Once you start doing it, it’s pretty smooth and zen like, just takes time going through the rests during the decoction. Felt pretty good to step up my game.
      Some people say it’s not worth it, but from what I can tell, at least for a bohemian Pilsner, there is a definite difference. Without any water adjustments apart from the distilled water addition, the single infusion mash is dying out during the fermentation, I’m not sure if it’s going to even work out because of the lack of calcium and other minerals, whereas the decoction batch is totally rocking. it looks and smells amazing, next time I’m going to get the urquell lager yeast, looking forward to july when I can try it!!

      • Yeah, I think you’ll like that Urquell yeast. I used it for my Bohemian Pilsner (just finished the last bottle the other day), and enjoyed it quite a bit. And this is with single infusion, and no water adjustments.

        Looking forward to hearing about the official tasting of your decoction version!

        • I just bottled my light lager where I used Saflager S-23. I’ve used that in all my lagers so far and there’s a definite similarity in them because of the yeast, something I’m not fond of, so I’m looking forward to the Urquell strain. If it’s what they use, and I can pull off a decent decoction, I will be a very happy man. (and so will my father-in-law, if I get the Czech approval for it, that is! lol)

  2. Wow, impressive!

  3. Just to clarify: the term “today’s well-modified malts” goes back to 1940s in literature at the least and according to maltster Briess malt modification today is similar to that of the early 1900s.

    There is a difference between “well modified” and “fully modified”, yet, nearly every home brewer confuses the two. Well modified malts include your typical “brewers” 2-row and brewers 6-row. These malts are good for decoction but you might not want to do a triple decoction with them. Pilsner malt is also well modified yet it is suitable for triple decoctions. PALE malt (2-row) is fully modified and not suitable for decoctions (this is for both the American and English pale malts).

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