Mint Julep Ale 1.0

We have a lot of mint growing outside our house.  I always wondered if you could make a mint julep style beer with it.  I had envisioned a beer that was basically amber colored, with mint added late in the boil, and aged on some bourbon-soaked oak chips.  Then I visited the now-defunct Fate Brewing in Boulder, Colorado, and tasted their Mint Julep Ale. It was quite good, which convinced me to brew my own.  Theirs included rye malt in the grist, which worked well with the mint, but didn't feature any actual bourbon.  I decided to add rye to the recipe I'd been considering, and to soak the mint in some bourbon apart from the oak chips, then blend in the mint-soaked bourbon at bottling time. Since corn is a big part of bourbon and I happened to have 3 ounces lying around I didn't want to go bad, I added that in last-minute.

Ingredients

6 pounds 2-row Pale Ale Malt
1 pound Crystal 60L Malt
4 ounces Rye Malt
3 ounces Flaked Corn
1 ounce Acid Malt
0.42 ounces German Northern Brewer hops @ 4.8% AA (60 min.)
0.25 ounces German Perle hops @ 7.2% AA (15 min.)
0.25 ounces German Perle hops @ 7.2% AA (5 min.)
1/8 tsp. Brewtan B (mash)
2 tsp. pH 5.2 Stabilizer (mash)
1/4 tsp. Brewtan B (boil, 20 min.)
1/4 Whirlfloc tablet (boil, 15 min.)
1/2 vial White Labs Clarity Ferm (fermenter)
1 package Safale US-05 yeast (fermenter)
10 liters (2.64 gallons) mash water
6.3 liters (1.7 gallons) sparge water

According to BeerSmith, the beer has the following characteristics:

• Batch Size: 2.64 gallons (2.5 actual)
• BJCP Style: 34.C  Experimental Beer
• Original Gravity: 1.064 SG estimated (1.072 actual)
• Pre-boil Gravity: 1.049 SG estimated (1.055 actual)
• Final Gravity: 1.012 estimated (1.018 actual)
• IBUs: 23
• SRM: 15.7
• ABV: 6.9% (plus Bourbon and Everclear)
• Fermenter used: Spock
• Bottling wand used: Stainless 2 
• Carbonation method: mix of Coopers and Brewer's Best drops
• Estimated Brew House Efficiency: 66.2% (vs. 62% expected)

Mash Schedule:

• Load 10 liters into the Brewie+
• Mash in at 104F for 20 minutes
• Load 6.3 liters into the Brewie+ for sparging 
• Mash at 120F for 20 minutes
• Mash at 140F for 30 minutes 
• Mash at 158F for 30 minutes 
• Sparge at 168F for 20 minutes 

Boil Schedule:

• 75 minutes: No additions
• 60 minutes: German Northern Brewer
• 20 minutes: Brewtan
• 15 minutes: German Perle, Whirlfloc 
• 5 minutes: German Perle 

Fermentation Plan:

• Days 1-3: Ferment at ambient basemen temp of 69F (no temp control)
• Days 4 through end of fermentation: 80F
• Add bourbon soaked oak chips near 67% attenuation
• When oak flavor reaches desired level, add mint to taste and bottle

Notes and Observations

07/12/2019:  As with other recent batches, I decided to load the water into the Brewie myself, to ensure that the exact amount was loaded.  I measured the water with an accurate scale and a plastic pitcher. It was then loaded into the Brewie and measured.

Pre-boil volume was around 13.8 cm deep, which is approximately 12.1 liters or 3.4 gallons.  Post-boil this should end up about 10.1 liters, and post-chilling it should be 9.7 liters or 2.56 gallons.  Gravity registered 13.1 Brix on the refractometer or an estimated 1.055 SG.

Tragedy struck just as the Brewie+ brought the wort to a boil. I noticed in the app (and later on the machine's control panel) that the wort was dropping in temperature... 190F... 180F... 170F... 160F...

I went down to check on it and nothing seemed amiss, so I tried shutting it down, unplugging it, waiting a bit, plugging it back in, and turning it back on. It asked if I wanted it to continue the previous brewing session. I told it to go ahead... and watched as the temperature continued to fall.

The wort boiling in my 8-gallon Mega Pot with induction cooktop

Grabbing the 8-gallon kettle from my extract brewing days, I quickly rinsed it and had the Brewie+ pump all the wort into the kettle. While it did that, I setup my induction cooktop and got it ready to go.  I shutdown the Brewie+ and unplugged it, using that plug for my cooktop. A little while later, I had the wort boiling nicely. I set a timer for 75 minutes and followed the boil schedule above.

While boiling, I cleaned up and sanitized my old immersion chiller and another kettle.  When the boil was over, I fished out the hop strainers and let them drain into the kettle.  Once they'd drained, I transferred the wort into the kettle with the immersion chiller and let it sit for a couple of minutes to further sanitize everything.  Then I kicked on the cold water and chilled the wort down to around 78F, which was as low as I figured I could get it with our summer ground water.

I transferred the wort into a sanitized fermenter, then dropped in a sanitized Tilt Hydrometer.  The gravity read a bit high, so I added distilled water to bring the volume up to 2.5 gallons and swirled it well.  When things settled, the gravity read 1.070 SG and the temperature read 77F.  That was a bit too high for my yeast, so I decided to let it chill a bit more in ambient basement temperatures.

I contacted the support folks for the Brewie+, hoping there might be an easy fix like a blown fuse or something, but it may be some time before I hear from them. They are based in Hungary.

07/13/2019:  I let the beer chill on its own from 77F to the ambient basement temperature of 69F before pitching the yeast. The yeast went in around 3pm and an airlock was placed on the lid. I'm planning to leverage the basement air to keep the fermentation within its ideal 64-82F range.

07/18/2019:  The beer is currently at a gravity of 1.023 SG, down from 1.025 yesterday.  I'd like to see it keep going a bit more but don't plan to do anything more than rousing the yeast, as glucoamylase is a bit too strong and unpredictable.

07/20/2019:  Here are the gravity readings since yeast pitch, showing the highest and lowest gravities registered each day:

• 7/13/2019: 1.072 to 1.071
• 7/14/2019: 1.071 to 1.056
• 7/15/2019: 1.056 to 1.034
• 7/16/2019: 1.034 to 1.024
• 7/17/2019: 1.026 to 1.024
• 7/18/2019: 1.024 to 1.023
• 7/19/2019: 1.024 to 1.023
• 7/20/2019: 1.024 to 1.023
• 7/21/2019: 1.024 to 1.023
• 7/22/2019: 1.023 to 1.022 
• 7/23/2019: 1.023 to 1.022 
• 7/24/2019: 1.022
• 7/25/2019: 1.022
• 7/26/2019: 1.022 to 1.021
• 7/27/2019: 1.022 to 1.021 
• 7/28/2019: 1.022 to 1.021
• 7/29/2019: 1.022 to 1.021 
• 7/30/2019: 1.022 to 1.020 
• 7/31/2019: 1.021 to 1.019 
• 8/1/2019: 1.020 to 1.018 
• 8/2/2019: 1.019 to 1.018
• 8/3/2019:  1.019 to 1.018

It appears likely at this point that we've reached final gravity.  I had expected the gravity to be a fair amount lower, but it looks like the mash schedule may have left too many unfermentable sugars behind because US-05 is a pretty solid fermenter

One day last week I picked fresh mint, chopped it up with herb scissors, and covered it in Everclear to extract the mint flavor from it.  Within hours the Everclear had gone from clear and colorless to a dark emerald green.

At 12:30pm, I added some oak chips soaked in Larceny Bourbon (a wheated Bourbon) into a stainless tea strainer ball and dropped them into the fermenter.  The chips had been soaking in Bourbon for weeks, so they should have plenty of flavor.  I saved the remaining bourbon (which had a few chips in it I couldn't easily get out) in case I needed to add a bit more flavor before bottling.  My plan will be to taste the beer every day or two until the right Bourbon flavor and oak flavor is reached. Then I'll transfer to a bottling bucket and add the mint extract until I get a good level of mint flavor, and bottle it.

07/27/2019:  I did a taste test. The rye comes through mostly as a slight sweetness. The oak chips and bourbon have made a mild flavor contribution, but I'm looking for a bit more, so I'm going to give it another few days. If it's still mild, I'll drop in more Bourbon-soaked oak chips until the flavor works, or start adding some of the bourbon the oak has been soaking in.  I don't really want to take the risk of infection associated with transferring to a secondary fermenter, but I may have to do that if it takes too much longer to impart the oak and bourbon flavors.  Gravity is currently registering at around 1.022 SG.

08/03/2019:  Another taste test revealed only a hint of oak flavor and virtually no Bourbon. I'm going to give it another week. If it hasn't picked up flavoring by then, I'll need to transfer it to a secondary fermenter to ensure that no autolysis takes place and creates off-flavors and continue aging it.  Gravity is currently reading 1.019 SG.

08/10/2019:  Today the oak flavor was solid, so I decided it was time to bottle. I transferred the beer off the yeast and into a clean fermenter for bottling.  Then I added Larceny wheated Bourbon until it suited my taste, about 3 ounces.  I ended adding all the Everclear-soaked mint to achieve a nice but subtle balance.  It was then bottled using Coopers drops in most, and 4 Brewer's Best tablets in the others.