Back in April I described a trip to a distillery, where we bought a whiskey barrel (which we have since christened ‘Rotunda’) with the intention of filling it full of very strong Imperial Stout. That barrel is 200L, but there are three of us
filling it. Well today Ladies and Gentlemen, I am please to announce that 40L of the future contents of that barrel have been wrested from non-being into being, by me. Incipit Diogenes! (Diogenes is what I, at least, am referring to the beer as, for reasons explained in the aforementioned post. Peter, on the other hand calls it ‘The Virgin Birth’, but then he’s a deeply religious man)
There will be about 100KG of base malt alone in this brew, and a couple of KG of hops, so we decided to order in bulk. We bought 1 tonne of malt on a Pallet from England (Bairds), the delivery of which was a joyous occasion. Peter (who I told you was deeply religious) offered supplication to the malt gods that Rotunda would prove a fertile vessel. Kev clutched 25KG of black malt wondering what the hell we were getting ourselves in to. Of course we didn’t keep all this malt, we shifted much of it onwards to our friends and fellow brewers at the ICB, but we are certainly malted up for the foreseeable future. This beer is also highly
hopped, but luckily a friend was passing by Charles Faram the hop merchant in Worcestershire recently, and we were able to buy some Kilos of Magnum and Cascade at wholesale prices. My living room smells divine, and I’m wandering around in a hoppy daze.
So with our ingredients sorted, we set about formulating a recipe. It looked to be the case that even with only 20L batches, there would be over 12KG of malt in the mash, which I already discovered is my coolerbox’s limit. We came up with a fairly standard Imperial Stout recipe, containing black malt, chocolate malt, and roast barley, along with the grainy beauty of amber malt. For bittering, we went with the cheapest high alpha hop, which at the moment is the Hallertau hybrid Magnum. Magnum is also a good all purpose bitterer for things like IPAs, so it won’t go to waste. For flavour, we decided to use cascade, although not normally associated with this style. Apart from the malt, there will be flavours from the barrel, the oak and the whiskey, and so anything less assertive might have gotten lost. Cascade is normally associated with pale beers, but actually the Americans put it in stouts and porters all the time. Also the more traditional Fuggles and Goldings are quite expensive at the moment, and since we bought the cascade in bulk we wanted something versatile that we could use in plenty of other brews. We are
pragmatists after all.
Yeast is another important factor- with a beer this big, it’s important to pitch lots of healthy yeast, so two weeks ago I brewed a fairly standard porter, with an OG of about 1.050, and I pitched in a packet of Wyeast 1084 ‘Irish Ale’ yeast, the classic stout yeast that is supposed to have originated in a certain well known brewery down the road. So yesterday armed with copious amounts of malt, hops and yeast I was ready to brew the monster.
The plan was to do two 20L brews back to back, I got up early and got going. I added calcium chloride flakes to the mash in order to get that malty profile that we need. Our recipe involved Pale Ale Malt as a base, with roasted Barley, Amber, Chocolate and Black Malts. We used Magnum to bitter, and Cascade at the end. Our yeast was the classic stout yeast, WYeast 1084 “Irish Ale”
The grain bill was huge, and difficult to stir as I was doughing in, there just wasn’t much space. I think it was the philosopher Wittgenstein who said in Philosophical Investigations that “The limits of my mash are the limits of my world”, or something like that, and now I see what he meant. I mashed it with about 30L which means a ratio of about 2.5/1, which should be ok.The runoff came in under the expected gravity though, even though with a grain bill this size we were banking on lower than normal efficiency (65%). I think I worked out that the efficiency must have only been 60%. My OG for the first batch came in at about 1.100. The second was about the same but I had a little more wort than expected, 22L. When both brews were in the fermenter the OG was 1.095, which is a bit below target, but then I’m confident that my beer will ferment lower than 1.029. I have a feeling I’ll get closer to 1.020, which means we should be close to the projected ABV, which is the theoretical limit of the yeast anyway, at about 12% alcohol it begins to die. We’ll just have to wait and see how low it goes! I have plans to improve efficiency next time. I don’t think it was a sparging issue as I fly sparged the second batch and it didn’t make a difference. My runoff could be too fast, also the tap is at one end of the mash, which could be causing uneven drainage, so I’m going to run a pickup tube into the middle of the mash tun. We
have another couple of goes at this to get it right.
I did get a second beer our of these mashes though, a stout at OG 1.053, which is pretty good for second runnings! It also explains where all the excess sugar went, and it is some compensation for the poor efficiency of the first brew. It will also serve to keep the yeast in motion, for the second batch of this next week.
As well as pitching enough yeast, good aeration is paramount, but I find that I get plenty of aeration by just opening the tap and letting the jet of black ambrosia shoot out the two feet or so down to the fermenter, and lots of good aerating splashing occurs. Fermentation was already vigorous when I got up the next morning, after only 7 hours. As you can see, there was already a thick 3 inch head of Krauesen formed. When I got back that evening, there had clearly been a bid for freedom from the stout,
but thankfully not much had escaped. It really made a mess of the fermenting box, the whole lid and sides were covered with gunk. I cleaned and sanitised the lid and the top of the box, and replaced it to finish fermenting. After this furious fermentation I’ll be surprised if it doesn’t ferment to a reasonably low final gravity. More reports when we have them!