The Beerening: Decoction Mashing, Take 2

Recently, my boss went on a business trip to meet with out clients in Germany and while he was there discovered Kellerbier.  Kellerbier, sometimes referred to as Zwicklebier or Zoiglbier, is sort of a German lager version of British cask ale.  It's a very young, fresh beer, often served just a few weeks out of primary fermentation with very little carbonation.  Unlike cask ale, to which a fining agent like isinglass is added, kellerbier is usually very cloudy due to a lack of extended secondary fermentation.  It contains much more proteins and yeast than traditional lager which has been filtered or aged for weeks or months at very low temperatures.

Not much kellerbier is produced commercially and even less of it makes its way to the states, but I did manage to find a bottle of Mönchshof Kellerbier at my local liquor store.  After drinking this and reading about the style a little, I set about trying to make my own because I found it an interesting challenge to try to duplicate a traditional style with origins dating back to the middle ages by description alone.  Also, trying to impress my boss with a home-grown version of a beer he really liked would probably not go amiss.

What I had tasted was a beer towards the dark side of golden, pretty well balanced without much overt hop character.  The beer had a pale malty backbone, evoking buttermilk biscuits.  It had a slight aroma of the herbal character European hops are known for as well slightly sulfurous twang of lager yeast.  With all this in mind I started to think about a recipe.

Since the unfortunate Wee Heavy incident I've been favoring simple grists and using the process or other means to achieve certain kinds of complexity.  This is really similar to Drew Beechum's "Brewing on the 1's" idea from his NHC lecture, see the video here.

Schloss Westtor zweikatzen mit zweimaischverfahren altbier im keller

10lbs Munich
1lb Flaked Barley

1oz German Northern Brewer @ 60 minutes
1oz Perle @ 5 minutes

Ferment with Wyeast Bohemian Lager (2124)

As I mentioned in the last post a decoction mash is a mash where you pull an amount of the thick mash and boil it in a separate vessel before adding it back to the main mash to raise the temperature.  This is a good way to do a mash with rests at multiple temperatures when you're not able to directly heat your mash, like if you're mashing in a wood vat or...a Rubbermaid cooler.  Beersmith's default double decoction schedule includes a 35 minute protein rest at 122F before adding the first decoction, which is why I included the pound of flaked barley.  Low protein rests like this can sometimes be detrimental to modern malts, actually breaking down too many proteins and ruining the beer's head and mouthfeel while having the opposite affect on older, less modified malts.  A low temp protein rest like this is recommended when working with significant amounts of flaked grains, so I added some.  I would use decoction boils to step up to 147F and then 156F before mashing out at 168F.  All this would get me an OG of 1.052 with 36 IBUs.  Also, I'm using the Bohemian Lager yeast because of the Lager Workarounds episode of Brewing TV, where they fermented that strain at ale temperatures and still had the beer turn out very lager-like.  Or at least, that was the plan.

When I got to the homebrew supply store I found that at some point during the week a crowd of thirsty brewers intent on making their Marzens for Oktoberfest had descended on the shop and cleared it of Munich malt.  So I had to modify my malt bill.  So, err...ahem

Schloss Westtor zweikatzen mit zweimaischverfahren altbier im keller

2.5lbs Munich
3.75lbs Vienna
3.75lbs Pilsner
1lb Flaked Barley

1oz German Northern Brewer @ 60 minutes
1oz Perle @ 5 minutes

Ferment with Wyeast Bohemian Lager (2124)

My mash was a downright disaster.  Unfortunately instead of using Dawson's 1qt thick mash/1lb grist formula from the Brewing TV Decoction Day episode, I elected to trust Beersmith's decoction volumes and only pulled 7 quarts for my first decoction instead of 11.  I boiled the decoction during the protein rest, but when I added it back in I didn't quite hit 147F.  I had to pull a few more quarts and boil again to make up the difference before starting the beta-saccrification rest.  My second decoction, which I started just a few minutes later was plagued by similar conditions.  So while I've technically performed a viermaischverfahren, I'm going to continue calling this the double decoction it would have been had I listened to Michael Dawson.

One thing I should mention, since I didn't know this when I was just reading about decoction mashes.  When you pull the thick mash it will be very dry looking, like a porridge without enough water.  It will have very deep cracks and seem like it'll scorch long before it bubbles.  It's not needed to add more water because as the mash sits on the heat getting stirred it will soften up and liquid will come out of it.  It's similar to making egg nog, when you add the sugar to the yolks it's very dry and crackly, but as you mash it it slowly becomes a thick syrupy liquid.

Also, this took me by surprise as well.  When you decoction mash, I think because of the protein rest you get this weird film that settles on your grain bed.  It looks kindof like break material from the boil, which it sort of is since it's also coagulated proteins and peptides.  It's nothing bad, it just looks really weird.

Check it.

As my punishment for misplaced trust, I was mashing for almost 5 hours.  When I finally went to sparge, it was absurdly cloudy.  I normally don't recirculate, but I felt like I had to this time.  Also, it was draining incredibly slowly.  I'm not sure if there is something wedged in my braid/valve or if the sparge was sticking as a result of degrading the grain husk material by boiling it.  Eventually I managed to collect just over 6 gallons of 1.049 SG wort, which slightly undershoots the volume I was hoping to collect, but is a slightly higher gravity than what I was predicting.  I probably could have drained a little more but it was taking forever.

I've yet to have a problem with DMS from using pilsner malt, but I decided to err on the side of caution and extended my boil to 75 minutes.  I hit my boil, waited 15 minutes and started my regular boil schedule adding Northern Brewer, Irish Moss, and Perle at the appropriate times.

When the boil was done I chilled down, but after running for about an hour I was only down into the 70s.  By this point I'd been at it for almost 9 hours, so I decided to just rack to the ferment, leave the sediment in the kettle instead of trying to strain it out and call it a day.  I wound up pitching a 2L starter of Wyeast Bavarian Lager into 4 gallons of 1.053 OG wort.  If I leave the fermenter directly in front of an air conditioning vent I discovered I can get down into the mid 50s, which is perfectly adequate for a primary lager fermentation.  Since this is a kellerbier, I won't be doing a long and cold secondary fermentation.

It's taken about 40 hours to start showing signs of life, so I'm going to let it ferment as cold as I can justify keeping my apartment for about 14 days.  Then I think I can let it rise to the high 60's, maybe 70 for 2-3 days for something resembling a diacetyl rest before racking it to the keg where I'll probably condition while carbonating under about 8PSI at 45F for a week before starting to serve.  Here's hoping it works out.

Drink on!
--PXA