Sunday, June 30, 2019

Strawberry Mead (Melomel) 1.0

While shopping in a Wal-Mart a couple of months ago, I decided it might be fun to try making a strawberry mead.  I picked two items off the shelf to combine with water, yeast nutrient, and yeast to produce the mead.

After the mead finished fermenting, the strawberry flavor became minimal or non-existent. This may be in part due to the high attenuation of the yeast used, which dried the mead out completely.  If I did this again, I would use a less attenuative yeast and more of the strawberry preserves.  That is not to say this isn't a good mead. It's just dried to the point that any strawberry character is imperceptible, at least to me.  It finishes more like a dry white wine.

Ingredients

1.5 gallons of tap water
5 pounds of Generic Honey
27 ounce jar of Welch's All-Natural Strawberry Preserves
2 tsp. DAP
2 tsp. Wyeast Yeast Nutrient
2 packages Crossmyloof Mead Yeast

Just these, water, yeast, and nutrients...

Characteristics of this batch:
  • Batch Volume:  2.1 gallons
  • BJCP Criteria:  M2C.  Berry Mead
  • Original Gravity: 1.111 SG (per Tilt Hydrometer)
  • Final Gravity: 1.008 SG estimated (0.995 SG actual)
  • Fermenter Used: O'Reilly
  • Bottling Wand Used: not yet bottled
  • ABV:  13% estimated (16.67% actual)
The water was brought to a boil. The honey and strawberry preserves dissolved into it, and left with a lid on it to cool to room temperature in a swamp cooler.

The strawberry preserves most likely contained some form of preservatives that would inhibit yeast growth, so I plan to overpitch the yeast and loaded it down with nutrients to help it out. I also planned to hit it with pure oxygen before pitching, to nudge it even further along.

Fermentation Plan

In Steve Platz's The Complete Guide to Making Mead, the author suggests fermenting at 62-75F, which fits in with my ambient basement temperature.  The planned schedule, per the book is:
  • Day 1 (6/30):  Brew, oxygenate, and pitch yeast.  
  • Day 2 (7/1):  Stir twice during the day, about 8-12 hours apart.
  • Day 3 (7/2):  Stir once, and add 3/4 tsp. yeast nutrient. Stir again 8-12 hours later.
  • Day 4 (7/3):  Stir twice during the day.
  • Day 5 (7/4):  Stir once, add 3/4 tsp. yeast nutrient. Stir again 8-12 hours later.
  • Day 6 (7/5):  Stir twice during the day.
  • Day 7 (7/6):  Stir once, add 3/4 tsp. yeast nutrient. Stir again 8-12 hours later.
  • Day 8 (7/7):  Stir twice during the day.
  • Days 9+:  No stirring or adding nutrients. 
  • Day 21:  Transfer to secondary fermenter and add finings, or bottle. 


Post-Brew Notes and Observations

06/30/2019:  Finished prepping at 2:15pm.  At 4pm temp was down to 134F.  At 5pm, 108F.  At 8:30pm, the temp was down to 79F and the gravity read 1.111 SG.  The must was aerated with pure oxygen for 60 seconds and two packages of yeast pitched to ensure success,

07/01/2019:  This morning I swirled the fermenter to stir up the contents.  Tonight, I sanitized a stainless steel spoon and stirred the must vigorously as indicated in the Platz book, before re-sealing the fermenter.  Gravity is down to 1.103 SG (about 7% attenuation) in about 23 hours since pitching the yeast.  The mead has a decidedly strawberry aroma, though it's an unappetizing brown color, probably because I should have waited to add the berries until it had cooled down. Lesson learned for next time.

07/02/2019:  I swirled the fermenter before leaving for work, after adding yeast nutrient, and again when I returned home.  Gravity is down to 1.096 SG now.  This represents about 14% attenuation in approximately 46 hours since the yeast was pitched, so you wouldn't exactly say this yeast is a very fast fermenter.

07/03/2019:  It's now over 72 hours since the yeast was pitched.  Gravity has dropped to 1.060 SG, which represents approximately 46% attenuation and 7.5% ABV.  Temperature crept as high as 73F but has been decreasing during the last hour.  With tomorrow being the July 4 holiday, I decided to give the yeast a dose of energizer and a good swirl before going to bed.

07/04/2019:  It's over 4 days.  Gravity is down to 1.039 SG, which represents approximately 66% attenuation and an ABV around 10.8%.  There doesn't seem to be any indication of it slowing down at this point, so it will be interesting to see where this ends up.

07/05/2019:  The mead was dosed with nutrients one final time and stirred very well with a sanitized spoon.  It's currently reading a gravity of 1.030 SG, which represents 70.3% attenuation and an ABV of 12.09%.  Temperature is 72F and the mead has held an average of 73F throughout fermentation. A sample removed using a sanitized turkey baster showed a light color, a little bit of a boozy aroma, and a flavor that is still sweet - with strawberry and honey notes, while still tasting "young" (as it should).

07/06/2019: Gravity is down to 1.012 SG today, and there is still regular airlock activity.  The temperature has dropped to 71F.  The current gravity represents 88.3% attenuation and 14.46% ABV.  I swirled the fermenter this morning and added a teaspoon of the pectic enzyme I received today to help clarify the melomel by breaking down the pectin. It should have been added earlier but I didn't have any, or really know about it at the time.

07/07/2019:  Gravity is now being reported as 1.000 SG (identical to water) by the Tilt Hydrometer and the temperature has dropped from 71F yesterday to 69F today, which is roughly the ambient basement temperature surrounding the fermenter.  I think it's safe to say that fermentation is probably complete at this point, though as always I'll adopt a "wait and see" approach.  I'll give the melomel a few more days to ensure that fermentation is indeed finished, then transfer it off the yeast cake so that it can clear up before bottling. The 1.000 SG gravity puts the mead's ABV at 16.02%.  Strong stuff...

07/11/2019:  Gravity now reads 0.995 SG, which represents an ABV of 16.66%.

07/18/2019:  The gravity held for three straight days, so I transferred the liquid off the yeast cake to ensure that it didn't pick up any autolysis flavors or aromas, and am going to let it continue resting until it gets clear, then we'll get it bottled and allow it to age.

07/20/2019:  The mead is looking clearer in the fermenter, but I suspect it will need a lot more time to get really bright and clear.

07/28/2019:  The meat is very clear when poured into a glass. The earlier harshness in the flavor and aroma are gone. It now comes across as much like a dry white wine. The strawberry flavor is more or less gone at this point, which leads me to question possible next steps... Do I bottle as-is, since it's quite drinkable?  Do I add a sterilant to kill off the yeast and back sweeten with honey, maybe adding strawberry flavor?  Or do I add oak chips and take the flavor closer to a white wine?  Perhaps doing all three might be worthwhile... so I can effectively get three meads from a single batch.  Bottle some now, split off the rest into two containers, and treat each differently.

08/25/2019:  I bottled half the batch as it was, and racked a gallon off to another fermenter where medium-toast French Oak chips were added.  I tried adding strawberry flavoring to a sample of the mead, and it really did not sit well with me, so I abandoned that idea.  The un-oaked sample tastes quite a bit like a dry white wine.  The oaked version has picked up some nice flavors from the oak, but I'm continuing to let it age on the oak until the flavor seems optimal.

08/27/2019:  A sample of the oaked version of the mead is very reminiscent of a Chardonnay wine.  It's very clear as well.  I'm planning to bottle it this weekend and allow it to age for a few months before trying it again.

Sunday, June 9, 2019

Bender's Olde Fortran Malt Liquor 1.0

The Matt Groening television series Futurama has long been one of my favorites.  On that show, the robot named Bender was frequently seen chugging bottles of a beer called Olde Fortran Malt Liquor.  There's no way to guess how a fictional beer on an animated television show might taste. We can guess from the label, which is a parody of Olde English Malt Liquor, that it might be something like that. The American Home Brewing Association web site listed a clone recipe for Olde English. I started there.

Since Bender belches fire after drinking Olde Fortran, I figure it has to be a strong beer. Since it's implied in several episodes that Bender has no taste buds (though this is sometimes comprehended), it's probably a cheap lowest-common-denominator kind of mash. I'm going with 6-row malt and a fair amount of flaked corn for the grist.  Since I want it to have at least some flavor, I'm going to add Mandarina Bavaria hops at the 15 and 5 minute marks to impart some mandarin orange notes.  Lastly, since we've seen Bender belching fire after every drink, I figure it must be strong. I'm going to aim for 14% ABV, which should tax the Oslo yeast pretty well.

Ingredients
7 pounds 6-row Malt
6 pounds Flaked Corn
1 pound Lyle's Golden Syrup
3 pounds Amber DME
Image result for futurama bender
Bender holding a bottle of Olde Fortran
0.21 ounces Summit Hops at 17.5% AA (60 min.)
0.50 ounces Mandarina Bavaria @ 9.2% AA (15 min.)
0.25 ounces Mandarina Bavaria @ 9.2% AA (5 min.)
1/8 tsp. Brewtan B (mash)
2 tsp. pH 5.2 Stabilizer (mash)
A few ml. of Glucoamylase Enzyme liquid (at mash in)
1 tsp. Yeast Nutrient
1L starter of Bootleg Biology Oslo Yeast
16.1 liters mash water (18.3 cm deep in Brewie+)
5.7 liters sparge water (6.5 cm deep in Brewie+)

BeerSmith 3 estimates the beer will have the following characteristics:
  • BJCP Category: 34.A Clone Beers
  • Batch Size: 2.5 gallons estimated (3.25 actual)
  • Original Gravity: 1.130 SG estimated (1.100 actual)
  • Pre-Boil Gravity: 1.093 SG estimated (1.063 actual)
  • Final Gravity: 1.035 estimated (1.007 actual)
  • IBUs: 32
  • SRM: 10
  • ABV: 8.8% estimated (13.5% actual)
  • BU/GU Ratio: 0.317
  • Boil time: 120 minutes
  • Fermenter used: Nomad
  • Bottling wand used: Stainless wand #1
  • Carbonation method: 1 Coopers carbonation drop per bottle
Mash Schedule:
  • 10 minutes mash in at 104F
  • 25 minutes beta glucan rest at 120F
  • 60 minute rest at 140F for fermentability
  • 15 minute rest at 158F for additional sachharification
  • 20 minute sparge at 168F
Boil Schedule:
  • 120 minutes:  Add DME and dissolve well
  • 60 minutes: Summit hops
  • 15 minutes: Mandarina Bavaria hops, yeast nutrient, whirlfloc
  • 5 minutes: Mandarina Bavaria hops
  • 0 minutes: Chill to 80F, oxygenate with pure O2 for 90 seconds
Fermentation Plan:
  • Hold at 85F until 67% attenuation is reached, using blow-off tube and temperature control
  • Raise to 98F until FG is reached
  • Rest at ambient temperature 1 week before bottling
Following fermentation, the plan is to bottle the beer with one Coopers carbonation drop per bottle and condition one week at 80F to ensure carbonation.

06/09/2019:  The Brewie+ loaded more water than requested. so I had to scoop out the overage to get the mash and sparge water amounts right.  I added pH 5.2 stabilizer, Brewtan B, and as much glucoamylase enzyme as a small pipette could pick up. The enzyme would help to ensure full conversion of the starches in the barley and corn. An iodine test performed well before the mash was over showed full starch conversion.
Post-Brew Notes and Observations


Image result for olde fortran
Olde Fortran on the shelf
I must have calculated mash and sparge water amounts incorrectly, as the pre-boil volume was an estimated 16.7 liters at a gravity of 1.063 SG (per adjusted refractometer reading).  To raise the gravity to where I expected it to be, I added 3 pounds of Munton's Amber DME.  This brought the gravity back up to where I needed it.

A little over an hour into the boil, the volume registered 14.5 liters and the refractometer showed the gravity at a bit more than 1.100.  I kept the lid off the Brewie to ensure that boil-off was increased to as much as 4 liters per hour, which I hoped would get the beer down to the desired gravity and volume by the end of the boil.

When the boil was over and I pumped the chilled wort into the fermenter, I was disappointed to find that I had well over 3.25 gallons at a gravity of only 1.100 SG instead of the planned 1.130.  I placed 2 liters in the flask with half of the Oslo yeast I'd grown in it, to grow more. Three gallons went into a 3.5 gallon stainless fermenter.  About a quart was dumped down the drain to leave head space in the fermenter.  The beer was oxygenated with pure oxygen for 45 seconds to help the yeast grow. The yeast was pitched, a blow-off tube was attached and the temperature control system configured to raise it from the initial 83F to 85F and hold it there.

About 2 hours after the wort was added to the 2L flask, it had a thick krausen on it and showed lots of CO2 bubbles coming up from the bottom.  The 3-gallon batch was showing signs of fermentation starting as well, with minor gravity changes appearing in the readings.

06/10/2019:  The gravity in the main fermenter has dropped from 1.100 to 1.056 (44% attenuation in under 24 hours).  I've raised the temp a little and swirled the fermenter to keep things moving.  The yeast was clearly happy in its new home.  It blew up out of the fermenter, through the blow-off tube and into the bucket under it. This occurred even with the SS Brew Tech fermenter's generously-sized blow-off tube.

The 2L sample on the stir plate blew off the cover during the night and left a bit of a mess on the surface where it was sitting, but there is plenty of indication of ongoing fermentation still.  I am a little concerned that the slightly ajar lid may have allowed wild yeast or bacteria into the fermenter. I'll have to check this before using it to ferment the next batch.

06/11/2019:  The gravity is down to 1.045 today.  I raised the fermenter temperature to 89F to encourage the yeast to keep going toward the final gravity.  It's definitely slowed down since yesterday but is still going. I'll probably keep raising it a bit each day to keep fermentation moving on.

6/13/2019:  Gravity seemed to have stalled around 1.043, so I added a couple of drops of glucoamylase enzyme to the fermenter. This kicked fermentation off again. This morning it's reading 1.017 SG which means it's about 12.1% ABV.  There are no signs as of yet that the fermentation has ended, either, so it may end up at the theoretical 14.2% ABV target.

6/13/2019 9pm:  Here's a testament to the power of glucoamylase. This morning, gravity was 1.017 SG. A little more than 12 hours later, the gravity is down to 1.012 SG. That represents 12.8% ABV and an apparent attenuation of 88.1% (which exceeds Bootleg Biology's upper limit of 86% for the Oslo yeast).  I suspect at this point that we'll end up down at 1.000 SG eventually - that's how effective glucoamylase is.

06/15/2019:  The gravity has held at 1.009 SG for about 24 hours now, which represents 92% attenuation and 13.3% ABV.  I'm hoping it holds here until I bottle it, as this would leave a decent amount of flavor in the beer while still allowing it to pack the kind of punch Bender would appreciate.

06/18/2019:  Gravity is down to 1.007 SG and has been there for the last 52 hours.

06/19/2019:  Gravity has held at 1.007 SG for 72 hours, so the beer is ready to bottle.  Tonight I unplugged the temperature control to allow the beer to cool down a bit prior to bottling.

06/21/2019:  The beer was bottled tonight, using one Coopers carbonation drop per bottle for priming. Yield was 23 twelve ounce bottles and 4 sixteen ounce bottles.  The beer is a deep amber color with an aroma reminiscent of orange peel. The flavor is pretty well balanced between malt and hops, perhaps being slightly sweet from the high ABV. There is a mild orange flavor from the Mandarina Bavaria hops and a clear warming note.  If it carbonates, I think it might end up being a very tasty beer.

06/27/2019:  Anxious to see how it turned out, I opened a bottle tonight. Unfortunately, it had very little carbonation.  Still, it has a nice flavor with a definite orange note. There is a clear warming note to it as well, though it is quite drinkable.  I labeled the bottles tonight and put them back in the 83F hot box to help encourage carbonation.

07/06/2019:  After about 15 days in the 85-90F hot box, the beer has not carbonated.  I can't say I am surprised by that, given that the fermentation probably pushed the yeast to its limit and the yeast has a tendency to fall out of suspension very well. There may not be much yeast in the bottle, and what is there might not be healthy enough to carbonate the beer.  I'm going to try two different methods to see if I can get some carbonation... One will be to flip the bottles upside down and hold them for a while, allowing the yeast to fall back through the beer toward the cap, then place them back right-side-up in the hot box. I'll do this nightly for a week with all the bottles.  The other thing I'll do is pick a subset of the bottles (about 6) and inject some rehydrated and active CBC-1 yeast in there, treated with a little fermaid, to see if that gets the carbonation I need.  CBC-1 is intended to handle up to 16% ABV, so it may be hearty enough to carbonate this beer.  We'll see.  If the "flipping over" method gets the carbonation going, I won't bother with CBC-1, but if flipping doesn't work and CBC-1 does, we'll have our answer.

07/18/2019:  It's now had almost a month to carbonate, but it's still flat. Fortunately, those who have tasted the flat version have enjoyed it anyway.

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.

Wednesday, June 5, 2019

Brewing High-Gravity Beers

After enjoying some of the high-gravity beers available in Ohio (and in Colorado during a visit), I began wondering how brewers were able to coax yeast beyond the range I had managed up to that point. I'd gotten a beer as high as 14% ABV without much trouble, but I'd never tried going beyond that.  I wondered how high I could get it.  I succeeded beyond my expectations, pushing the beer in question beyond 20% ABV.  That's higher than one of the professional brewers I spoke with, who regularly brews high-gravity ales and has done so for several years.

Below is a condensed series of tips I've collected. These have come from the White Labs WLP099 product listing, online forums, other articles on the Internet, and verbal conversations with other brewers.

Grist and Mash
  • Realize that you're probably going to get a lower brew house efficiency on these high gravity beers than you get on lower-gravity batches. You'll have to compensate for that with more grain, adjuncts, malt extract, or a longer boil in some cases.
  • Depending on your system, you may not have enough capacity for grain to reach your target gravity. You can compensate for this by:
    • Using malt extract
    • Using adjuncts like honey, maple syrup, candi sugar, corn sugar
    • Using a multi-stage brewing process, where the wort from the first batch becomes the mash and sparge water for the next
    • Boiling much longer than usual to further concentrate the wort
    • Pulling off some of the wort and boiling it much harder in another kettle
  • You want to aim for a very fermentable wort, because there is a good chance the yeast could give out before you reach your target gravity. You'll want to make it easier on them by breaking down the sugars as much as possible.
  • One way you can make the wort extremely fermentable is to use glucoamylase enzyme or papain, often used in Brut-style beers.
  • Wort pH during the mash should stay between 5.0 and 5.3
  • Aim for an original gravity of 1.106 to 1.120 initially, and add fermentables later. This will keep osmotic pressure on the yeast low.  (White Labs suggests starting with a wort that would produce a 6-8% beer and adding fermentables during the first 5 days of fermentation.)
Boil
  • As noted above, boiling longer will help concentrate a weaker wort
  • Hop utilization in high gravity brews is lower, so hop the beer more than you think you should. There is a kind of sweetness produced in the high-gravity beers, too, and the hops will help balance that out. (I've not yet worked out just how much you want to hop these beers more than normal to maintain balance.)
  • Add 2-5 times the amount of yeast nutrient you'd normally add during the boil.
Fermentation
  • The key here is to reduce stress on the yeast as much as possible. At a high level, this means:
    • Minimizing osmotic pressure by starting with a lower-gravity wort and adding concentrated fermentables
    • Giving the yeast a healthy environment with plenty of oxygen and nutrients
    • Inoculating the wort with a lot of yeast cells to compensate for the stress of the higher gravity wort
    • Keeping temperatures low to prevent off-flavors and ensure yeast health
    • Agitating the wort for the first several days to keep yeast in suspension
  • Pitch 3-4 times as much yeast as you would normally pitch for the size and gravity
  • Keep the fermentation temperature down to the lowest end of the yeast's optimal range. This will minimize the production of fusel alcohols and other potentially-unwanted byproducts from the yeast. It will also minimize stress on the yeast.
  • Until the yeast reaches 67% attenuation (approximately), you should do the following daily:
    • Add oxygen:  Aerate 5-10 minutes with a pump or 30 seconds with pure oxygen. Aerate about 4 times as much as you normally would.
    • Add nutrients:  Add a fresh dose of nutrient
    • Agitate:  Swirl the fermenter to get the yeast into suspension and help distribute the oxygen and nutrients
    • Add fermentables: Add sugars and/or concentrated wort daily for the first 5 days, until your target gravity is achieved.  After all fermentables have been added, keep doing the other steps above until 67% attenuation is reached.  
    • Be sure to keep detailed notes on these additions, including weighing your fermentable additions. If you wind up with a great beer, you will want to be able to reproduce it, and these notes will prove important.
  • After 67% attenuation, I recommend continuing to agitate the yeast until final gravity is reached or the yeast stalls out.
  • If fermentation seems to be slowing or stalling, add another yeast strain with higher attenuation and alcohol tolerance to help keep the process going.  
    • Champagne yeast is one option
    • CBC-1 Cask and Bottle Conditioning yeast is another
    • If it's appropriate to the style, adding Brettanomyces is another option
  • Be patient. It took about two weeks to get my one-gallon test batch to 20.7%.
  • Adding some sanitized wood chips is a way to offset some of the sweetness of the beer and introduce barrel-aged flavors.
Post-Fermentation
  • The beer may show a lot of "green flavors" when it is young. The solution is to age it for a longer time, possibly even a few years, until it mellows and becomes pleasant to drink.
  • Note that hop character changes over time, so if your style is one that relies on hop flavors, you'll want to taste the beer (perhaps monthly) to figure out its optimal aging time.
  • Keep notes on what you did to brew, ferment, and age the beer so that if you decide to re-brew it you will be able to reproduce the beer as you liked it best.
  • It's difficult to create balance in a high gravity recipe. Starting with an established winning recipe could help. 
I plan to do some additional high-gravity experiments this year and talk with pro brewers when I can, and may update this post as I learn new things about the process.