Saturday, June 8, 2019

Oslo Doppelbock 1.0

Early bottle before carbonation
I know what you're thinking... "Oslo is in Norway. The Doppelbock style is German. What in the world is an Oslo Doppelbock?"  Am I right?  I'll assume I am.

The German Doppelbock style is one of my favorites, and I've never brewed one.  At first, that was because I didn't have the equipment to properly lager a beer.  Now, it's because it's summer in Ohio and the temperatures are way outside the range you'd want to brew a Doppelbock in.

There's been a fair amount of buzz lately about the various Kveik yeast strains. Bootleg Biology's Oslo strain is described as producing "beautifully clean, lager-like beers at temperatures as high as 98F without noticeable off flavors. At the high end, beers can finish attenuating in as little as three days! This culture's versatility and neutral flavor profile allows you to effortlessly produce most beer styles."  Now you see where Doppelbock combines with Oslo to form "Oslo Doppelbock"...

In other words, I'm attempting to produce a Doppelbock-like beer using the Bootleg Biology Oslo yeast strain, to see how it holds up against a German style where the judging criteria tell us we need a clean lager character and a very malty beer.

The BJCP tells me I'm looking for the following qualities in the finished beer:
  • Appearance:  Dark brown with ruby highlights. Good clarity. Large, creamy, and persistent head.
  • Aroma:  Strong maltiness, toasty, little to no (noble) hop aroma, moderately low dark fruit character, slight chocolate-like aroma, but no roasted or burnt aromatics.
  • Flavor:  Very rich and malty, significant Maillard products from decoction mashing, some toasty elements, a very slight chocolate flavor, moderately low dark-fruit flavor is optional, and overall it's fairly malty sweet with an impression of attenuation.
  • Mouthfeel:  Medium-full to full bodied. Moderate to low carbonation. Slight alcohol warmth.
Those are the notes I'll be trying to hit.

Ingredients

5 pounds Avangard Pilsner Malt
2 pounds Dark Munich Malt
14 ounces Swaen Melany (Melanoidin) Malt
10 ounces Briess Carapils/Dextrine Malt
2 ounces Carafa Special III Malt
2 ounces Dingeman's Special B Malt
0.85 ounces German Hallertau hops pellets @ 4.1% AA (60 min.)
0.05 ounces German Hallertau hops pellets @ 4.1% AA (15 min.)
1/4 tsp. Wyeast yeast nutrient (15 min.)
1/8 tsp. Brewtan B (mash)
1/4 tsp. Brewtan B (boil, 15 min.)
1/2 vial White Labs Clarity Ferm (fermenter, for gluten reduction)
1.5 tsp. pH 5.2 Mash Stabilizer
Half of a 2L starter of Bootleg Biology Oslo Kveik Yeast
12.7 liters mash water (Dublin Ohio tap) - 14.4 cm deep in Brewie+
6.7 liters sparge water (Dublin Ohio tap) - 7.6 cm deep in Brewie+

No water treatment was employed for this batch.

According to BeerSmith 3.0, this beer should have the following characteristics:
  • Batch Size: 2.5 gallons estimated (2.8 gallons actual)
  • Boil Time: 120 minutes
  • Brew House Efficiency: 62%
  • Original Gravity: 1.078 SG estimated (1.071 SG actual)
  • Pre-boil Gravity: 1.054 SG estimated (1.054 SG actual)
  • Final Gravity: 1.011 SG estimated (1.023 SG actual)
  • BU/GU Ratio: 0.344 estimated
  • IBUs: 27 estimated
  • Color: 21.8 SRM estimated
  • ABV: 9.0% estimated (6.4% actual - apparent attenuation 66.3%)
Other notes:
  • Fermenter used:  McCoy (3-gallon Fermonster)
  • Bottling wand used:  Stainless #2
  • Carbonation method:  1 Coopers carbonation drop per bottle
Some quick notes on the ingredients above and why I've used them:
  • I wanted some authenticity, so I used German malts as the base. Pilsner and Munich are common for Doppelbocks.
  • The Oslo yeast is a high attenuator, and could leave the beer thin.  To help add back some of the body, I've added a generous dose of Carapils and Melanoidin malts.
  • Melanoidin malt also is said to contribute flavors commonly associated with decoction mashing, which is frequently done in brewing Doppelbocks. Since I won't be decoction mashing, I'm hoping this will get the flavor closer to the ideal.
  • Carafa III is there primarily for color.
  • Dingeman's Special B is there to contribute some malt complexity and add the dark fruit notes that are prized in the darker Doppelbocks like this one is intended to be.
  • The combo of Carapils and Melanoidin should give us a nice head, at least in my experience.
  • Hallertau hops are used in Ayinger Celebrator, one of my favorite Doppelbocks. Although it's not exactly to style, I'm adding a small amount at 15 minutes to hopefully impart a little German flavor and aroma.  I am a little concerned it will take the beer off-style but then the Oslo yeast may do that anyway.
  • I figure that even if the Oslo yeast fails me, this is a chance to quickly test this particular malt/hop recipe to see how I like it (if I do).
Mash Schedule:

Since the Oslo strain is a higher attenuator than many lager yeasts, I'm trying to balance out the beer by adding more dextrinous malts in the mash (Melanoidin and Carapils) and mashing at a higher temperature to leave more long-chain sugars behind that it may not fully ferment out.  Hopefully the result will be a full-bodied but well-attenuated beer.
  • 15 minutes mash in at 104F
  • 15 minutes mash at 153F
  • 45 minutes mash at 158F
  • 20 minutes mash out and sparge at 168F
Boil schedule:

I suspect that the Brewie+ doesn't boil quite as hard as most homebrew setups. The result is that my beers are often accused of lacking malt complexity, which would kill a Doppelbock in competition. I've tried to overcome this by using a more complex malt bill, step mashing, and extending the boil. Given that a recent Dry Irish Stout took third place in its category after using these techniques, I think this is working. For that reason, I'm extending the boil on this Doppelbock to a full two hours.
  • 120 minutes:  No additions
  • 60 minutes: 0.85 ounces Hallertau hops pellets
  • 15 minutes: Brewtan B, Hallertau, and yeast nutrient
Post brew, the wort will be chilled to 80F and pumped into a 3.0 gallon PET Fermonster fermenter.

Fermentation plan:

Oslo reportedly ferments clean as high as 98F, but its optimal range is 80F to 98F.  I'm planning to configure my temperature control setup to hold the beer within the optimal range, which in theory should result in full attenuation in as little as 3 days.  We'll see.
  • For the first 7 days, the beer will be held at 80F to allow the Oslo yeast to do its thing. No cooling will be employed during fermentation, only heating to keep it at no less than 80F.
  • After 7 days, assuming the beer has reached final gravity and seems to be holding, it will be bottled. 
Conditioning plan:
  • The bottles will be held at 80F for 3-5 days, then allowed to rest at ambient temperatures for another 2-4 days.
  • If carbonation is adequate at 5-7 days and there are no off-flavors like diacetyl or off-aromas in place, the beer will be chilled to refrigerator temperatures for 1-2 weeks and a tasting against the BJCP criteria will be performed.
  • The beer will be cellared and allowed to continue bottle conditioning until the fall.  At that point, if it's any good, I'll enter it into a competition and see how it does.
Post-Brew Notes and Observations

06/08/2019:  I configured the Brewie + recipe to load 9.7 liters of mash water.  It loaded 8.5 this time, so I topped it off with Ice Mountain Spring water to the 12.7 liters of mash water I needed.  The Brewie+ was configured to load 5.7 liters of mash water, and loaded 7.9 liters. I removed some of this and got the level down to 5.7 liters.

The volume came up higher than expected at about 2.8 gallons and the gravity 1.071 SG instead of 1.078 SG, which is going to make the beer weaker and more bitter than intended. Hopefully the yeast will do its thing and still deliver a decent Doppelbock.

I split a 2L yeast starter into this batch and another 2L starter to prep for the next batch.  The Oslo strain is difficult to obtain, so I want to get as much value from it as possible.

06/09/2019:  I pitched the yeast around 10pm when the wort was approximately 76F.  Since then, the fermentation has kicked off quite well and the temperature has held at 80F.  Here's an hourly capture of gravity readings from the Tilt hydrometer:
  • 6/8/2019 10pm:  1.071 (yeast pitched)
  • 11pm: 1.070
  • 6/9/2019 12am:  1.077 (this increase usually indicates very active fermentation)
  • 1am: 1.070
  • 2am: 1.065
  • 3am: 1.065
  • 4am: 1.064
  • 5am: 1.062
  • 6am: 1.060
  • 7am: 1.058
  • 8am: 1.057
  • 9am: 1.055
  • 10am: 1.051
  • 11am: 1.048
  • 12pm:  1.046
  • 1pm: 1.045
  • 2pm: 1.042
  • 3pm: 1.041
  • 4pm: 1.042
  • 5pm: 1.039
  • 6pm: 1.038
  • 7pm: 1.037
  • 8pm: 1.037
  • 9pm: 1.036
  • 10pm: 1.034 
  • 11pm: 1.034 (That's 56% attenuation in 24 hours!)
06/10/2019: Gravity is down to 1.027 SG today, so fermentation is clearly slowing.  I raised the temperature a little and swirled the fermenter to rouse the yeast into continued activity.

06/11/2019:  Gravity is down to 1.025 SG today.  The fermenter temperature has been raised to 87F to encourage the yeast to keep going.

06/13/2019:  Gravity seems to be holding at 1.024 SG, which is at the upper range of a Doppelbock in the BJCP criteria. It doesn't look like fermentation has completely stopped yet, so the gravity may go a point or two lower before it stops.

06/15/2019:  Gravity is down to 1.023/1.024 SG today and has been holding that number for about two days now. If it holds another 24 hours, I'll bottle it.

06/19/2019: The beer was bottled tonight using one Coopers carbonation drop per bottle. A sample extracted at the start of bottling had a very clean, malty aroma. The flavor was balanced, with lots of good dark malt flavor to it. I couldn't pick out any elements from the yeast, so it seemed pretty clean to me.

06/29/2019:  I opened a bottle, but it had virtually no carbonation despite spending a week in an 83F hot box. My suspicion is that the Oslo yeast flocculates so well that there may not be much in the bottle to carbonate the beer.

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