Rum Barrel Imperial Stout

Today I'm brewing a version of WeldWerks Achromatic Stout that I've brewed in the past. This is an Imperial Stout, and this will go into a recently acquired rum barrel I got from nearby Cotherman Distilling Co. in Dunedin, FL. This is a big beer, but still drinkable and I think it'll work really well in a rum barrel.

My new-to-me rum barrel is only 5 gallons, smaller than I usually like to use; I prefer 10 gallons at a minimum, but preferably 15 and 30 gallon barrels. Reason being, the well-documented fact that volume to surface ratio isn't ideal with smaller barrels. First, they tend to extract wood character much more quickly so over-oaking can be a concern. Second, you tend to have larger losses to Angel's Share, increasing headspace which can lead to oxidation issues with long-term aging. This barrel has already gone through a few fills, so the risk of over-oaking is reduced. To reduce the risk of oxidation and Angels' Share losses, I decided to wax the entire barrel (both heads and all staves) with beeswax. This will reduce micro-oxygenation via capillaries in the wood, so it should allow me to age the beer longer than if it wasn't waxed. I've used this method on other smaller barrels and it's worked great. 

My process for waxing a barrel is melting beeswax or paraffin in a double boiler, painting it onto the exterior of the barrel (spread it as thin as possible while coating the wood evenly), then hitting it with a heat gun. The heat gun will re-melt the wax allowing it to penetrate into the wood and excess wax to drip off the barrel. Oh, one note here, be sure to spread out a tarp, drop cloth, or something similar to protect surfaces from dripping wax. For a small barrel like this, I used a large piece of aluminum foil to catch dripping wax. 

Here's the recipe as I'm brewing it today, which is a slightly different version than the previous versions:

Target OG: 1.105

Target FG: 1.030

IBU: 45

ABV: 10.0%

13.625# Crisp Marris Otter

14oz Simpsons Chocolate Malt (*cold steeped)

14oz Weyermanns Chocolate Rye Malt (*cold steeped)

14oz Crisp Pale Chocolate Malt (*cold steeped)

14oz Simpsons DRC

11oz Simpsons Light Crystal

11oz Flaked Oats

3oz Crisp Roasted Barley (*cold steeped)

42g Magnum (FWH)

1g BrewTan B (Mash)
Whirlfloc (Flameout)
Wyeast Nutrient (10 min)
4.66g BCAA (10 min)
LalBrew® House Ale Yeast

Zinc Buddy

Cold steep roasted grains (1lbs/2qts RO/Distilled water) overnight. Last time I added the cold steeped liquor near the end of the boil and it diluted the wort quite a bit. This time I'm adding it at the beginning of the boil.

Mash at 153F, collect ~7-7.25 gallons pre-boil volume (including steeped dark grains), 120 minute boil. Start fermentation at 60F, ramping up to 65F over 5 days. Transfer to CO2-purged barrel once primary fermentation is complete (~2 weeks). I plan to start tasting samples at about the 2 month mark in the barrel. 

Note: This recipe is based on the Chocolate Achromatic Stout, but it works well without the chocolate additions. For the Chocolate version (5 gallons), add 8oz of roasted cacao nibs and one vanilla bean after fermentation is complete. Leave cacao in for 1-3 days (taste daily) and remove when desired character is achieved. Leave the vanilla bean in for 2-3 weeks then transfer for packaging. Or...do The Bomb Tincture method which simplifies the process and yields excellent results. 

Water Profile

Target Water Profile
Ca	Mg	Na	SO4	Cl	HCO3
50	5	33	35	45	140

The last time I brewed this was in Utah where the tap water is great for brewing dark beers. Florida has pretty hard water which is usually great for dark beers as well, but it can be a little sulfury. I'm going to use Beersmith's Black Full water profile for this beer. To 11 gallons of RO/Distilled water, add: 

• 3.6g Epsom Salt
• 3.8g Calcium Chloride
• 5.6g Baking Soda
• 2.9g Chalk

Brewing Notes

My first runnings gravity was much lower than in the previous batch. I suspect channeling through the grain bed may have occurred. I usually add rice hulls but skipped them this time, which is likely the cause of the unexpectedly large drop from target gravity. To compensate, I had some dark DME on hand in case the end-of-boil gravity fell short of my 1.105 target. With about 10 minutes left in the boil, I added 1.25 lb of Briess Traditional Dark DME. For future batches, I may switch to my 20-gallon mash tun, as the shallower grain bed should reduce compaction and the risk of channeling  

Starting volume in the kettle was about 7.25 gallons.

Session Readings
Beginning mash pH	5.27
Ending mash pH	5.25
1st running gravity	22.2 (1.090)
Pre-Boil gravity*	15 (1.059)
Pre-Boil pH*	5.19
Post-Boil gravity	26 (1.106) 1.1059 per Tilt
Post-Boil pH	4.96

*After adding steeped grain liquor.

Read more...