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Mellow Midnight Imperial Stout


Here we are, it’s finally time to put my 12% Imperial Stout down for a nice long twelve month nap. To quickly recap, I’m brewing a huge imperial stout, and trying my best to mimic the barrel aging process for the beer. I’ve been wanting to brew a beer like this for a quite a long time, so it feels really good to finally get moving with it. I’ll skip over most of the barrel aging process, as I covered that in my last post.


For this recipe, I borrowed heavily from my prior Imperial Stout. I felt that beer turned out really nicely, so I wanted to carry over as much as I could. The main goal here was just to amp up the gravity to the 1.120-1.125 range to finish out around 12-13% ABV. To get there, I’m adding a couple pounds of 2-row, and I’m cheating with a couple pounds of DME. My efficiency starts to fall off a cliff around 1.100, so using DME for a beer like this becomes really attractive. Considering it’s such a small percentage, and I really don’t want to boil this beer for 3-4 hours, DME it is. Lastly, I added another quarter ounce of Apollo to get another 5IBU or so. Everything else with the recipe is the same.


The next step was charring 1oz of oak cubes. I got my propane torch, some water, and headed into the garage. I torched the cubes on one to two sides until they turned bright orange, and then doused them out with water. Those went into a few ounces of Maker’s Mark for three weeks before they were strained and dropped into the beer. You can see the difference in the color of the two bourbons in the picture at the top. One is Maker’s Mark straight out of the bottle, and the other is Maker’s after 3 weeks of soaking.
The brew day for this beer was interesting. Any time you cram something like 27lbs of grain into a 5 gallon batch it always is. I started off by getting a huge starter of WLP090 going. I don’t tend to worry too much getting 9-10% beers to the finish line, but 12-13% without using exotic yeast can be tough. I used 2 vials in a 5L starter for this one. As for the brew day, it was fun. I mashed for 60 minutes as usual. I also added a little extra water to the sparge volume for efficiency’s sake, since this was a 120min boil. The first runnings of the beer were 21 Plato, and my gravity after the 2 hour boil was 27.75 Plato. This was a little under my target of 28-28.5, but I’m not too stressed about it. Next year, I’ll boil the batch for another 30minutes, I had extra wort left over. I skipped the whirlpool for this one, and started chilling right away. It’s always interesting just how much thicker wort like this is than a normal gravity beer. Anyway, after chilling to 60F, I hit the beer with a solid three minutes of oxygen before pitching the yeast.


Despite rigging up a blow off tube, I’m always surprised by how much yeast blows off of an Imperial Stout. I lost about a half gallon of wort, but I think something like 25% of the yeast must have blown off. Things really slowed down after 3 days, and at 5 days the gravity was still chilling at 1.048. After ten days I was still at 1.033. It took almost a full three weeks to hit a final gravity of 1.026. My only theory on what took so long is that the massive blow-off resulted in a large loss of healthy yeast, and maybe that slowed down the race to the finish. I’m not entirely sure. Either way, the beer tastes really great at this point, and the final gravity was in the range I was looking for.

Brewed: 12-7-15
Kegged: 12-27-15
Oaked: 12-28-15
OG: 1.118
FG: 1.026
ABV: 12.1%
IBU: 50
6 Gallons

23lbs 2-row
2lbs Munich
10oz Roasted Barley
10oz Chocolate Malt
8oz Carafa III
8oz English Med Crystal (55L)
6oz C120
2lbs DME
Mash at 151*
1.75oz Apollo @ 90
.75oz Apollo @ 15
WLP090 – Super San Diego Yeast
1oz Medium Plus American Oak Cubes – Charred, and soaked in Bourbon

And that’s about where this story ends for now. I just got done racking the 12.1% stout into a keg, and tossed the oak cubes in a day later. My plan is to purge the pressure valve on the keg once every month or two to let in a tiny bit of O2 into the keg, and see where that gets me. The goal is to sit on this beer for close to 12 months so that it’s ready to go for Christmas 2016. I can say that the base beer turned out pretty fantastic for being flat and quite young. Unfortunately, we’ll have to wait a full year to get any conclusive results on how this little experiment went. Since time tends to be the hardest variable to quickly replace, I’ve already charred another 1oz of oak cubes, and I have them soaking in bourbon. If things go well with this year’s batch, the oak cubes will be ready to rock for next years batch.

Anyway, cheers for now, and Happy New Year!

25 thoughts on “Mellow Midnight Imperial Stout”
  1. Mateusz 01.04.2016 on 2:51 PM Reply

    Happy New Year Scott! (More post pls 🙂 )

  2. Ron Bermudez 01.04.2016 on 5:53 PM Reply

    Very nice. We are running almost parallels paths. I've been contemplating brewing bourbon "barrel" aged big stout for some time now. The tentative plan is to brew it in February. I have lightly toasted self-charred white american oak that's been soaking in Makers for a few months now. At what temp are you conditioning the beer? Stowed away in some cool closet, or in a temp controlled fermentation fridge for the 12 month duration?

    It's always a pleasure reading up on your latest and greatest beers.

  3. Dan Bronson 01.04.2016 on 11:04 PM Reply

    I would love to do something like this with port. Would you make any changes or just sub the bourbon for port? I'm not sure if toasting/charring the oak is appropriate.

  4. Ricky Rich 01.04.2016 on 11:09 PM Reply

    Happy New Year Scott! Awesome post. I'm eagerly awaiting Citra DIPA so hurry with that one will ya? LOL JK

  5. Scott 01.05.2016 on 1:54 PM Reply

    That's very cool. You'll have to let me know how it ends up turning out.

    I'm going to condition the beer at room temp. I figure letting the oak expand and contract will be a good thing. I'm stashing it away a closet in the coolest part of the house, but the keg will still see 60-64F in the Winter and 80+ in the Summer.

  6. Scott 01.05.2016 on 1:58 PM Reply

    I really don't have anything to add in regards to port. A quick google search leads me to believe port barrels are just toasted, but I would do a little more digging before jumping in.

  7. Ryan Faulkner 01.05.2016 on 2:19 PM Reply

    It's always great to read your posts. Thanks for taking the time to do this. What's the reason behind burping the keg and letting in a bit of oxygen??

  8. Matteo 01.05.2016 on 5:00 PM Reply

    Thank you for this post, and happy new year!

  9. John Rankin 01.05.2016 on 5:12 PM Reply

    Have you ever tried Fermcap-s?

  10. Ron Bermudez 01.05.2016 on 5:30 PM Reply

    My thoughts exactly… Yes, allowing the oak to expand and contract can only be a good thing. That's exactly why I intend to allow the oak to soak in the beer for the whole duration of the conditioning process while the keg sits in a coat closet. It'll probably see anywhere from a low of 65F in the winter to mid 70's in the summer.

  11. Vic 01.06.2016 on 9:02 PM Reply

    More (less) importantly, how was that double-oaked for 3 weeks Makers Mark?

  12. Scott 01.07.2016 on 2:18 PM Reply

    Oak Barrels allow a small amount of oxygen in. Less than a plastic bucket, but more than a stainless keg (which is virtually zero). A little bit of oxidation is required, but it's really had to tell how much I need.

  13. Scott 01.07.2016 on 2:19 PM Reply

    I have, but I find it really doesn't help much in the primary for me. I do find it to be a HUGE help in my blow off bucket. It keeps the bucket from overflowing into my fridge.

  14. Scott 01.07.2016 on 2:21 PM Reply

    Very different. Tons of vanilla, tons of caramel, tons of oak. The flavors the wood imparted are definitely the kind of flavors I'm looking for in the beer, so I have high hopes.

  15. Adam 01.09.2016 on 3:08 PM Reply

    Scott, did you add the Makers post-soak as well, or just the cubes? I've had a couple ounces of oak chips soaking in 12 year old bourbon for three weeks and I plan to add both the liquor and the chips to my robust porter for about 5-7 days, since the chips will transfer oak far quicker than cubes.

  16. Robin Hung 01.10.2016 on 8:57 AM Reply

    The 6 gallons in your recipe is pre boil or post boil volume?

  17. Scott 01.11.2016 on 5:32 PM Reply

    Pretty much just the cubes. A little bit of the liquor carried over, but it wasn't much.

    If you want bourbon flavor in a beer, and you're planning it age it on chips or cubes for less than 6 months time, I'm guessing you'll need to add bourbon directly.

  18. Scott 01.11.2016 on 5:34 PM Reply

    It's just the 'recipe size' I know I need to use to end up with 5 gallons in a keg. It's basically 6 gallon post boil. I usually can only take a little under 5.5 gallons into the fermenter, and finally 5 gallons into the keg.

  19. Adam 01.19.2016 on 2:57 PM Reply

    Scott, Did you use 100% RO water for this recipe (and other dark recipes)? and if so, did you simply skip your acid malt addition or did you find that you need to add something else to boost the pH?

  20. Scott 01.19.2016 on 8:51 PM Reply

    Ya, 100% RO water. I do skip the the acid malt for beers this dark. I don't have a pH meter, but the math says that should get me close.

  21. Aron 01.29.2016 on 6:38 AM Reply

    Really.interesting stuff and I'm planning on doing something similar. Just to be clear on the whole ventilating the keg thing. Does this means you are going to age it depressurized and just pulling the ventring once a month are you planning on repressurizing after venting or something?

  22. Scott 02.22.2016 on 11:01 PM Reply

    I really haven't thought that part through. I'm likely going to depressurize it, and then allow just a touch of O2 in. From some googling i've done, it doesn't look like barrels allow quite as much O2 in as people think.

  23. Cody King 03.09.2016 on 2:54 AM Reply
  24. Jason 09.14.2016 on 7:25 AM Reply

    Simple solution to yeast blow off that I’m considering, a Burton Union System.

  25. […] here we are over a year later. For those that need caught up, I brewed a 12% Imperial Stout a little over a year ago, with a plan to age it on charred oak cubes for 12 months. The goal […]

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