It has actually been over a year since my colleague Sven and I brewed our imperial stout: Employee Orientation 101. Now that the weather is colder and next year’s National Homebrew Competition (NHC) will be here before I know it. Time to brew another imperial stout is here. A big beer like an imperial stout needs a big pitch of yeast. One of my favorite methods to build up yeast is to brew what I call a starter beer. A starter beer is a lower alcohol and more lightly hopped beer that I can harvest yeast from in my next batch.
The yeast I want to use in my imperial stout is the same yeast as I used in my last imperial stout. I call this yeast my “House Irish Blend”. When I brewed Employee Orientation 101 last year, I took two expired yeast pitches, from two different suppliers, and made two yeast starters to build up enough cells.
At that time I also built up some extra yeast cells which I saved for future use. That was last November. Then in February I took that yeast, made a starter for Rundown Irish Red, then banked some extra cells which I didn’t revive again until now. I had to make two starters just to have enough yeast for my starter beer and build enough extra to save.
The jar of yeast I saved almost certainly contained less yeast cells to begin with than a fresh package of yeast contains. Combine that with the fact the jar was nine months old, it took almost a week to build up enough cells. My first starter only showed the faintest signs of fermentation after three days on my stir plate. I cold crashed my first starter, and stepped up to a larger starter. Given how sluggish the first starter was this was a bit of a leap of faith. Thankfully the second starter took off right away.
For the actual beer I decided to brew an English Porter. Two years ago I threw together an extract porter with leftover ingredients I had lying around. The base of the beer was Briess liquid malt extract. I was happy with how that beer came out and in the back of my mind have wanted to brew it again as an all-grain batch with English ingredients.
Behind Enemy Lines was my starting point. When converting to all-grain with Muntons malts I had to account for the fact that Muntons Chocolate Malt is much darker than Briess Chocolate Malt. I also chose to use a darker crystal malt, Muntons Crystal 400 (150L) to get more of a toasted flavor along with more raisin and molasses flavors as opposed to caramel.
I prepared my water the night before brew day and started to mill my grain. My grain mill jammed again. I adjusted the gap, ran a small amount through, thought it was fixed, then it jammed again. I need to completely disassemble the rollers and spray everything that moves inside the mill with compressed air and lubricate.
When I was finally able to run my malt through the mill the crush looked to be poor. It looked like far too many intact kernels made it through. To improve my crush, I ran the malt through the mill again. After the second pass through the malt looked like kibble, and most of the barley husks looked to be destroyed. The concern now was that the malt was too finely milled and would cause a stuck sparge. Luckily I had some rice hulls which made sure I was filter through my grain bed without any issues.
With the finer crush a funny thing happened, the efficiency of my mash went through the roof! Usually my mash efficiency is right around 70% which means I extract 70% of the available sugars from my malt. This batch was the highest efficiency I can remember: a whopping 85%!
The batch was supposed to be a sessionable English Porter with around 5% alcohol. My target original gravity was 1.050. Instead my original gravity was 1.062. At that point I could have diluted my wort. A commercial brewery that legally has to be within 0.3% of a beer’s declared alcohol level would almost certainly do that. Instead I decided to just go with what I had.
At this point the beer will be too high in alcohol to be an English Porter. Not that adhering to style is critically important, but I was curious what style would be the best fit. In my mind I thought the American Porter category while higher in alcohol than English Porter, was also has a prominent American hop character like the American Stout category. A declared style only really matters in competitions.
After reading the guidelines American Porter is, “A substantial, malty dark beer with a complex and flavorful dark malt character”. While bigger and roastier, American Porter can have an “American” or “British” character. With the dark Muntons Chocolate Malt and Crystal 400, this beer should fit the style nicely.
With a nice porter and a winter warmer in Welcome As You Are, I have plenty of malty ales to last through the winter.