One of the best winter-warming (though great all year) styles, the imperial bourbon-aged stout. Making a delicious, rich, and strong imperial stout does not have to be difficult! In this article, I’ll walk you through my simple imperial bourbon-aged stout extract recipe!
What Makes a Good Imperial Stout?
A good imperial stout is a complex beer with a solid roasty backbone, balancing bitterness, and may have dark fruit notes. An alcohol-warming sensation plays well with this style, but you also you don’t want this alcohol sensation to be overwhelming, hot, or sharp.
The grain bill for this style can vary from being fairly simple to extremely complex. One thing that it must contain is generous additions of roasted malt.
With this style, many all-grain homebrewers decide to add either additional sugar or extract to bump up the strength of this beer.
Aging these beers in bourbon barrels has become extremely popular recently. The flavors that barrel aging lends harmonize exceptionally well with these complex and strong beers.
However, most homebrewers do not have access to good quality barrels to age their beer in.
How to Bourbon-Age a Beer Without a Barrel
Fortunately, imparting the bourbon-aged flavors we’ve come to love is possible, even as a homebrewer!
Let’s talk about the options to obtain those bourbon barrel flavors we desire from the beer without the use of a classic bourbon barrel.
Oak Chips
Oak chips are likely the most well known way of adding oak flavor to your beer.
The advantage of chips are that they are small, easy to use, and cheap!
They do come in a variety of origins and toast levels, which will be discussed in detail below.
The downside to using oak chips is that due to their large amount of surface area contacting the beer, they will impart their flavor very quickly. This, in and of itself, is not necessarily a negative thing. However, it can become a problem if the chips are left soaking in your beer for too long.
The chips can start imparting harsh tree-like flavors after just a week in your beer, so you will want to watch and taste your beer frequently when soaking on the chips.
I recommend boiling oak chips for a short amount of time in water. This will sanitize them as well as extract some potential harsh flavors. Then, I recommend soaking in your spirit of choice. 1-2 weeks is generally sufficient for this.
Start with about 1 oz of oak chips per 5 gallon batch to avoid ‘over-oaking’.
Oak Cubes
Use of oak cubes is very similar to using oak chips. The biggest difference is that there is less surface area in contact with the beer when using oak cubes. Due to this, many brewers feel that they lend a smoother flavor than chips do. You can also let your beer soak on the cubes longer than you can the chips without as much risk of ‘over-oaking’.
They are just slightly harder to work with due to their larger size.
As with chips, these will come in a variety of origins (American, Hungarian, French) and toast levels.
I recommend preparing oak cubes the same way as oak chips.
Oak Spirals
Oak spirals are somewhat newer to the market, and some people absolutely love them!
Regarding flavors that the spirals impart, they tend to be between the chips and the cubes. As you can imagine, these spirals do offer lots of surface area to contact the beer. However, people find that the flavors are smoother and more complex than those imparted by oak chips.
Mini Oak Barrel
Lastly, the most attractive and expensive option would be to purchase a mini oak barrel.
I have not had the opportunity to try this yet, but it is something I look forward to experimenting with in the future.
Using a barrel like this will require much more preparation than oak cubes, chips, or spirals.
As with the other examples we discussed, this will have more surface area contacting your beer than a much larger traditional barrel. Thus, you will not have to age the beer for years like you see many breweries doing.
There are also concerns regarding oxygenation with these barrels. To a small extent, this oxygenation could be beneficial, but you also don’t want your beer tasting like cardboard. Some people do coat their barrels in wax to avoid this.
How to Prepare a Homebrew Oak Barrel:
To prepare the barrel, it is best to either soak or submerge the barrel in water for about 24 hours. This will swell the wood and help to seal the barrel.
You will then test the barrel by filling it halfway with water and checking for leaks.
Once you have ensured that there are no leaks, you will fill the barrel with either a neutral spirit such as Vodka and/or fill it with Bourbon. This will conveniently make your bourbon more delicious, as well as contribute bourbon flavors to the oak barrel.
It is important to either keep the barrel filled with either a solution of potassium metabisulfite/citric acid OR beer, wine, or a spirit to keep it from developing an infection.
Types of Oak
There are two main distinctions when it comes to oak products. The place of origin (ie American, French, Hungarian) and the toast level.
American Oak can impart flavors of campfire, vanilla, roasted coffee and butterscotch.
French Oak lends cinnamon, milk chocolate, coffee, and fruity notes. The fruity notes are often described as ‘jammy’.
Hungarian Oak generally lends a strong vanilla flavor, along with chocolate and black pepper characters. The coffee flavor is more subtle than American or French.
You will also see the oak come in toast levels from light, to medium, and heavy toast.
The flavors will change with the toast level. You will generally find more oaky flavors towards the light end of the toast; whereas, the roasty coffee, spicy, and vanilla flavors will come out as the toast gets heavier. Obviously, this is a generalization across American, Hungarian, and French oak.
Don’t Over-Oak
I would argue that the biggest concern over using any of these forms of oak in your beer is extracting too much flavor from your oak.
I’m making an assumption here, but you probably don’t want your beer ending up tasting like a tree.
My recommendation is simply to taste your beer frequently throughout the oaking process. A wine thief can come in handy for this technique. You can always add a bit more oak or bourbon to your beer, but unfortunately, can’t take those foresty flavors away!
Below is a very simple imperial stout recipe using the extract method. I used medium toast American Oak chips that were soaked in bourbon for about 2 weeks prior to putting in the beer.
Imperial Bourbon-Aged Stout Extract Recipe:
Stats:
Volume: 5 gallons (18.9L)
Original Gravity: 1.093
Final Gravity: 1.020
Predicted IBU: 46.06
ABV- 9.58%
Steeping Grain:
1lb. (453.6 grams) Chocolate Malt (350L)
0.5lb (226.8 grams) Roasted Barley
0.5lb (226.8 grams) Crystal 80L
Steep at 155F (68.3C) for 20 minutes
Extract:
6.6lb (3kg) Golden Light LME (60 minutes)
3.3lb (1.5kg) Amber LME (30 minutes)
1lb (453.6 grams) Golden Light DME (30 minutes)
Hops:
1.5oz (42.5 grams) Nugget (60 minutes)
0.5oz (14.2 grams) Columbus (20 minutes)
1oz (28.3 grams) Brewer’s Gold (10 minutes)
Other Additions:
1lb (453.6 grams) Belgian Candi Syrup D-180 (15 minutes)
8oz (226.8 grams) Brown Sugar (30 minutes)
1/2tsp (2.5mL) Irish Moss (10 minutes)
1oz (28.3 grams) American Oak Chips Medium Toast
Jim Beam Bourbon- enough to cover oak chips (approximately one ounce)
Water:
Local Flagstaff, AZ Tap Water
Yeast:
Safale US-05 (2 packets) Recommend making a yeast starter!
Directions:
Heat water to 155°F (68.3°C). Add crushed specialty grain and steep for 20 minutes. Remove steeping grain. Heat to boiling. Remove pot from heat, add both liquid and dry malt extract. Return wort to boiling. Boil for 60 minutes, following the hop schedule. Add Irish moss at 10 minutes.
After the boil, chill the wort to slightly below fermentation temperature, about 64°F (17.8C). Add water to bring up to 5 gallons (18.9L) total. Aerate the wort and pitch the yeast. Ferment at 67°F (18°C) for 2-3 weeks.
Boil 1oz (28.3 grams) of oak chips for 20 minutes. Discard water. Cover oak chips with whiskey or bourbon of choice for 2 weeks.
Transfer beer to secondary fermentor at 2-3 weeks. Add oak chip/bourbon mixture to secondary fermentor. Recommend using a large hop bag to contain your oak chips. Let oak chips sit in beer for 2-5 days, tasting to preference each day. Remove oak chips when desired flavor is obtained. Age beer in secondary for 1-3 months. Cold crash the beer to 35°F (1.7C) after fermentation has completed. Bottle or keg the beer and carbonate to approximately 2.25 volumes of CO2.
Tips:
How to Make a Yeast Starter
When you are trying to produce a high gravity (high strength/alcohol) beer, you will need lots of healthy yeast! The dry yeasts found in packets or liquid yeasts obtained from homebrew shops generally have enough healthy cells to perform average fermentations.
When you want to get above 8% or so ABV, you may need some extra help. This is where yeast starters come into play.
A yeast starter is essentially brewing a ‘mini-extract-beer’ to give your yeast a healthy start at replication.
You will boil a small amount of dry malt extract, just as you would brewing an extract beer. Place this ‘wort’ inside a sanitized vessel. Then pitch the yeast.
You will then need to continuously agitate this yeast starter for a couple days. The easiest way to do this is with a stir plate, such as this one. However, the cheapest way is to safely shake or agitate the vessel throughout these days.
The goal here is to build a strong and healthy yeast colony to eat up all the sugars your beer has prepared for it!
I do plan on doing a detailed article in the future about yeast starters, but until then, feel free to contact me!
Prolonged Aging Time
The more complex and strong a beer is, the longer it will need to age to reach its ideal flavors. For this beer, I found aging about two months in secondary was sufficient. However, I will say the bottles I have had about two years later are exceptional.
It is important to decrease oxygen exposure as much as you can when you are performing a long secondary fermentation. I prefer glass carboys with small necks vs. large buckets to reduce oxygenation.
Bottling Yeast
Due to the prolonged time spent in secondary, most of the yeast can fall out of suspension.
If you plan on kegging your beer, this will present no problems. However, if you plan on bottle conditioning the beer, there may not be sufficient yeast present to perform these duties.
The solution to this problem is by adding bottling yeast at bottling day along with your priming sugar.
I have had great success with Lallemand CBC-1 Conditioning Yeast for this.
How to Use a Wine Thief
Use of a wine thief gives you a quick, easy, and sanitary way of sampling your beer. This is especially helpful when you want to taste your beer as the oak chips are sitting in it.
A wine thief has a simple valve at the bottom that will allow you to pick up a small amount of beer without letting it drip all over the floor. Wine thiefs can also be used to a sample beer’s gravity using a hydrometer.
Get Creative!
This recipe, and most imperial stouts for that matter, makes for a great base beer for other additions. Feel free to get creative with it, and add some coffee, vanilla, cacao nibs, or even make it a full on pastry stout!
Thank you very much for stopping by!
If you do have any questions, I am active on both Instagram and Facebook. Please feel free to contact me there!
For information on how to brew using the extract method, please see my post here.
If you’re interested in learning more about brewing stouts, look no further than the Classic Beer Styles book on stouts!