Imperial Stout v1 - Black Ops and roasty bitterness

At time of writing the UK has been in lockdown for 65 days. It is oppressively warm weather and I'm hungover from drinking too much homebrew last night. What better time to start a homebrew blog?

I've been thinking a lot about imperial stouts, as one does when its lager weather.

My last attempt was interesting, fermented warm with an English strain that had the happy accident of producing a strawberry-like ester in the finished beer. This was somewhat ruined with my addition of extremely tannic oak barrel chips, which although had been soaking in Woodford Reserve for 6 months, still had enough astringency to fell a small horse. Alas.

ti-tannic - my first attempt sunk

But where to draw inspiration from? Looking at my UnTappd check-ins, there are very little surprises in my highest rated imperial stouts. Brooklyn's Black Ops, Founders CBS, Goose Island Bourbon County, Buxton Yellow Belly, Lervig 3 Bean Stout, countless Omnipollo, hordes of Mikkeller, a smattering of BrewDog. But this time I don't want to make a beer with lactose or barrel chips or blueberry waffle pancakes. I want to make a beer beer.

Black Ops is the gold standard for non-pastry imperial stouts for me. All molasses, black treacle and impossibly thick mouthfeel, with great bitterness that stops it being cloying. BYO has a clone recipe that I imagine would get us pretty close, although I'm surprised it uses two row as a base. Surely a more flavourful base malt would only do you more favours?

the gold standard

BYO also gives this an English yeast strain (London ESB) but I don't remember much yeast character at all, my assumption would be something more subtle like American Ale I or II..?

Regardless, this is the ball park for what I want to achieve - a wide variety of English and German malts, lots of roast and chocolate, very little yeast character and not ridiculously sweet. Let's work out the finer details...

Yeast

I have a surplus of US-05 in the fridge, which is a good start. In the early days of my homebrewing 'career' I remember my friend Mac (a much more experienced brewer) saying of the many beers he has made without US-05, he has almost always regretted not using it. As time goes on, the more I understand. Unfussy with temperature, tolerant of very high ABV and so clean you can almost forget its there, US 05 is perfect for when you want the yeast to shut up and for hops (or in this case malt) to do the talking. As I'm only brewing 5L, a whole pack of US 05 is a massive overpitch, which will really help fermenting a big beer without stressing the yeast. This beer will be in primary for around a month before being aged in keg, so autolysis won't be an issue.

the offending oak chips that
will not feature in this recipe

Water

My local corner shop sells very handy bottles of 5L water which is very soft (haven't tested it properly, I just know its way better than what comes out of our tap). Two of these should get us through brewing and sparging. BeerSmith thinks our pH will end up around 5.4, 0.2 higher than I would normally aim for, but in this case I will leave it as is. This is because I want the alkalinity to help balance the acidity of the dark malts, hopefully allowing more malt character and less acridity to come through into the beer. Bicarbonate of soda will be on hand incase I have miscalculated.

Hops

None of the beers I'm using for inspiration have a very distinct hop character, outside of their bitterness. Magnum is my first choice, as it has bucket loads of alpha acids and a very clean bitterness without any citrus or pine that could get in the way of our malt flavours. I also happen to have some in stock. Black Ops has an IBU of around 70, so that's what I'll aim for. This translates as 21g of Magnum in the boil for 60 minutes. One hop addition should suffice.

Which just leaves...

Malt

Out of all the base malts, I think Maris Otter should be the place we start. After all, its got most of the diastatic power of pilsner malt but with an added richness in flavour, more complexity; a maltier malt. Golden Promise would also work, but I have plenty of Maris Otter in stock, so let's go with that. I imagine this will be around half the grain bill.

When I think of a beer being 'malty', the flavour I am usually thinking of is Munich malt. 10.3% Munich should be a good foundation to build further malt complexity. Another 10.3% oats will help body and mouthfeel, as will the choice not to include any syrups or sugars other than that found in the malts. We want this beer to be THICCCCCCC (with seven C's).

What's missing? Roast, chocolate, SRM! All the fun stuff, in short. Chocolate malt seems sensible, as does the delicious Dark Chocolate malt Briess makes at 8.6% and 5.2% respectively. I also want to be fairly heavy handed with some roasted barley, which will do much of the heavy lifting where roast is concerned. 3.4% roasted barley is heavy handed, trust me, as I hopefully avoid an acrid ash tray beer, but we'll see how wise that is when it's brewed.

Finally, a variety of crystal malt featured in most of the recipes I liked while researching, adding a range of caramel and burnt toffee flavours as well some body and some somewhat unnecessary residual sugar. I am choosing to go for 50g / 1.7% each of 120L, 80L, 60L and Caravienne. Why? I don't really know. This is the part of the recipe I am most unsure about and will benefit from tweaking the most (I imagine).

Chatting to Advanced Cicerone and fellow bar manager Paddy Gardiner about this recipe is not making me feel any better about crystal malts. "I tend to avoid dark crystals and high roast malts cause of harshness, and get the colour and complexity from things like Munich, pale chocolate, brown, biscuit, etc. 120L crystal is just nasty!" Oh dear. Well, I guess let's keep it as just a whisper and hopefully it won't get too grim?

One stroke of genius Paddy did bring to the table was toasting some of the oats like Brulosophy did, resulting in an almost cookie-like flavour in the finished beer. The only downside is you really need to toast the oats and wait for them to 'settle' (i.e. for all the weird off flavours produced from toasting to dissipate). I was fairly keen to brew ASAP so let's stick this in our back pocket for a future iteration.

Our recipe so far then:

Quarantine Imperial Stout v1

(5 litre batch, all grain)

OG = 1.113 FG = 1.040
IBU = 70 SRM = 68.7 ABV = 10%+

A quick note: I'm fairly certain some of the above numbers are nonsense. BeerSmith seems to think US 05 will give up at 10% but I find this highly unlikely. Hence the massive FG. Although if this does finish up at 1.040, I can always rebrand it as alcoholic chocolate sauce.

Ingredients

1500g / 51.7% Pale Malt, Maris Otter (3.0 SRM)
300g / 10.3% Munich Malt (9.0 SRM)
300g / 10.3% Oats, Flaked (1.0 SRM)
250g / 8.6% Chocolate Malt (450.0 SRM)
150g / 5.2% Dark Chocolate Malt (568.0 SRM)
100g / 3.4% Roasted Barley (300.0 SRM)
50g / 1.7% Caravienne Malt (22.0 SRM)
50g / 1.7% Crystal 60 (60.0 SRM)
50g / 1.7% Crystal 80 (80.0 SRM)
50g / 1.7% Crystal 120 (120.0 SRM)

1 packet of Fermentis US-05
1 tsp Yeast Nutrient (Boil 10 mins)
21g Magnum (Boil 60 mins)

Mash & Sparge

Where many brewers would find an issue with mashing such a grain heavy beer (with some resorting to poly-gyle insanity), due to my small volumes I should be okay. Starting with 8 litres of water, mashing at 67 degrees, allowing for a litre or so of grain absorption and sparging with 2 litres more gets us to 9 litres pre boil. Lovely. For pictures of my mini brewing set up, click on About Me.

I'm keeping sparging to a minimum, not only to limit dilution but also to avoid any tannin from the dark roasted grain, which is a lot more of an issue with dark speciality malts than ordinary base malts.  I will have some Demerara sugar on hand just incase I really fuck up the pre boil gravity, but at this stage I'm optimistic.

Boil

There is an incredible range of boil times on the internet for imperial stouts, ranging from the sublime half an hour to the frankly frightening 6 hours or more. Who has this kind of free time? Even in quarantine? Baffling.

Provided I hit everything right up to this point, I think a 60 minute boil should suffice, as the wort should already be very dense. All we need to do is sterilise the wort and pull some bitterness from our hops. At the tail end of the boil I will add some yeast nutrient and some Irish moss, chill with my plate chiller and pitch rehydrated US 05 (and pray).

Fermentation

Fermentation will be around 18C in a 10 litre fermenter for a 5 litre batch to reduce the blow off to hopefully nil. I've seen reports of truly explosive fermentation online, especially with this style and would like as much of my beer to be drunk / not on my ceiling as possible.

Hell yeah it is

Brew day - 05/06/20

My lovely Malt Miller package arrived and it is finally time to brew! I really wish I had a stout to quaff along with while brewing, but alas I will have to make do with a few Verdant DIPAs. It is a hard life we lead. 

Our strike temp was 75 degrees C, calculated via BeerSmith and got up to temp with a sous vide stick. Once all the grain was added, this came down to 67 degrees, as I'd hoped. I let this mash for an hour, by which time it had fallen down to 64. I would love any tips on regulating mash temperature as my current system is far from perfect. If you have any ideas, please get in touch!

Our mash pH turned out perfect, thanks again to the magic of BeerSmith. As mentioned above, I really wanted this a little higher than the usual 5.2 to balance the acridity found in many dark roasted malts. I guess we'll find out if it worked?

Mash pH was bang on to balance acridity

As I have being getting more invested in water chemistry in the last few days, I decided to crack out the drug dealer scales and have a bit of a play with this recipe. BeerSmith has a water profile called Brings Out Maltiness & Bitterness which seemed apt for our Imperial Stout needs. 

The profile in question looks like this:

Ca: 80 Mg: 5 Na: 25 SO4: 80 Cl: 75 HCO3: 100 

To balance this with my own water profile, I cracked out my drug dealer scales and used 0.7g Epsom Salt, 0.6g Calcium Chloride 0.6g and 0.5g Baking Soda, getting us very close to the above profile. 

A few tweaks to the above recipe were made on the fly. Firstly, I was on to the very last of my Munich malt so thought I may as well use it all, resulting in 400g instead of 300g. Truly groundbreaking, I know.

Also, our mash was considerably less efficient than I had hoped, with a pre-boil gravity of 1.080 (our target was 1.100) and a post boil gravity of only 1.088 (our target was 1.113). I think this is partly due to my boil of rate not being correct, as my volume really doesn't deplete all that much. I also had a few dough balls, as with such a large grain bill it was tricky to pour and stir at the same time. I got around this with adding 600g of soft dark brown sugar, getting our OG bang on to 1.112. 

Once our OG was where it should be, I cooled with my plate chiller directly into a 10 litre carboy, half filling it. This will give the beer loads of oxygen to use during fermentation, which I will then rack into a 5 litre carboy for bulk ageing. 

The yeast was pitched at 18 degrees and the ambient temperature of my living room was 19 degrees, so I don't expect any yeast-derived off flavours. Within 24 hours it was fermenting vigorously.

A big ole krausen

First tasting - 12/06/20 - uncarbonated and very young

So it was time to transfer my baby boy from his 10 litre palace to his 5 litre apartment for extended ageing, as fermentation had just slowed down / stopped the day before. This seemed like a good time to take a gravity reading and have a sneaky taste. My hopes were not high this early on, but I was pleasantly surprised!

We finished out at 1.032, meaning we hit 11% ABV - ideal. But even better is the mouthfeel of a beer like this at .032! It is a truly glorious mouthfeel, almost like engine oil. The beer coats the glass, legs of alcohol staying for minutes, warming the back of my throat. 

There is, of course, some fusel alcohol drinking a beer this hefty just post fermentation, but it's fairly subtle. In fact, it's mainly on the nose, it really doesn't taste that boozy. Great clean bitterness balancing the sweetness, notes of dark chocolate, espresso and liquorice. Even better, there is no acridity from the roasted malts leaving just a great depth of malt flavour behind. A few months ageing and carbonation should do wonders. 

More updates to follow. 

A big lad