22 March 2009

posted by benjy edwards

No brewing this weekend, but I did rack the imperial stout out of the primaries to a couple of secondary carboys.  Gravities on both were 1.025, so no change from the gravity checked last week.  We will leave them in the secondaries for 6 or 7 months,  first at room temperature then followed by a period of cold-conditioning.  There is no need for imperial stout during summer, so I plan to keg the first half in time for the cooler weather in October or November.

14 March 2009

posted by benjy edwards

The imperial stout, “Son of Satan”, has been in the primary for one week now, so it is time to check on its progress.  It started out at 1.081 and today it was down to 1.025, which is an attenuation of 69% and an alcohol by volume of 7.4%.  That is good progress for a week, but I left the beer in the primaries for another week to allow it to drop a bit more.   If it gets down to 1.020 after six months or so of secondary conditioning, that would be 8% ABV.

The plan for now is to give it another week in primary, then rack to secondary for long-term aging.  When it comes time to keg, we’ll experiment with adding some cold-pressed coffee for added interest.

8 March 2009

posted by benjy edwards

The imperial stout fermentation is in high gear, so much so that one of the fermenters was overflowing into its airlock, plugging it up.  I caught it in time, removed it, and there was a rush of co2 and spray of yeast wort onto the sides and top of the inside of the fridge.  The pop noise it made made me wonder how much longer it would have taken before the carboy exploded from the pressure.  Hopefully the stopper and airlock would have blown out on its own before then.

High gravity stout fermentations have a tendency to get out of control.  The last batch of Son of Satan was named because of its fermentation activity, which erupted out of a stainless steel conical and filled the bottom of another fridge before flowing out the door and staining a carpet with black, sticky wort.  Temperature was kept at 66 to 68 in the first 24 hours of fermentation, now it is up to 70F to help the yeast attenuate.

7 March 2009

posted by benjy edwards

We’re wrapping up this run of the yeast with a bruiser of a beer, an imperial stout.  The best way to reuse yeast is to brew the batches in order of their original gravity, starting with the lowest.  This is because the higher ABV beers stress the yeast with the amount of alcohol that is produced, which is toxic to yeast, just like it is with people.

Our target gravity was 1.080, so not that strong by imperial stout standards.  The recipe was forumulated after researching many commercial and homebrewed examples, including North Coast’s Old Rasputin, B.O.R.I.S. from Hoppin’ Frog, Great Divide’s Yeti, an imperial stout from Brew Your Own magazine, and our own previous batch of imperial stout brewed in early 2006.

Along with Maris Otter, we added generous amounts of crystal and Special B, chocolate malt, black malt, and roast barley, plus aromatic malt, brown malt, and flaked oats.  The total grain bill was 38 pounds, which just barely fit into the mash tun at a water to grist ratio of 1.125 quarts per pound.  There was no room for any rice hulls to help with filtration of the oats, but thankfully this was not a problem.  In the boil we added a pound of dark candi syrup and achieved an original gravity of 1.081.  Hops were Northern Brewer and Phoenix for bittering, along with some First Gold and Bramling Cross for flavour.  We’ll give this batch a week or two in primary followed by many months in secondary to age.  Christened Son of Satan, it will be ready to drink when the weather turns cool again in the fall.

The milk stout from last week was needed on tap, so we racked half of it to a corny keg, force-carbonated it, and tapped it immediately.  It turned out even better than the first time we brewed it, with plenty of sweetness to balance the roast malt character.  At only 4.2% it’s a great session beer.  The other half was racked to secondary along with a spare gallon put into a gallon growler.