The first big stout I brewed at Jackie O’s (Athens, Ohio) was Dark Apparition in 2007. Back then, a beer finishing above 6° Plato (1.024) was considered pretty thick!
Initially my approach to building body and depth of mouthfeel was to incorporate a large variety and percentage of specialty malts. A large amount of darker crystal malts, chocolate malt, aromatic malt, and some oats would provide complex sugars that would not ferment and remain in the finished beer. Maxing out the mash tun and hitting a higher mash temperature, 154–156°F (68–69°C), were also standard techniques used at Jackie O’s in the early days. The mash-specific techniques created a beer that commonly finished around 5.5–6.5°P (1.022–1.026). As styles evolved and palates changed, the bigger beers needed a boost.
The brewing team at Jackie O’s moved toward a more concentrated mash and a longer boil and increased the addition of adjunct sugars during the boil. These new techniques took the starting gravity higher than 26°P (1.110), and we started seeing FGs closer to 8–10°P (1.032–1.040). The idea was that the yeast would slow down, unable to consume all that sugar. From there, the gravities got higher, yields got lower, and mouthfeel became more and more dextrinous. At times, we used maltodextrin and lactose to provide more residual sugar in the finished beer, but that was more recipe-specific than a technique that we used across all big beers.
At Private Press (Santa Cruz, California), I am using many of these techniques. I push to max out the mash tun, use a high amount of darker caramel malts and oats, keep sparging volumes very low, boil long, and shoot for more than 30°P (1.130). Most beers are providing ample mouthfeel without an overly cloying sweetness.
About the Mash
Get a good percentage of base malt, 75 percent. I usually make a nice European Munich malt part of that 75 percent. Using about 10 percent of some dark crystal, brown malt, or Cara varieties will build a lot of character and provide dextrins to the finished beer. Layering 5 to 10 percent oats into the mash will lend that soft sweetness and body. I usually mash around 152°F (67°C)—this temperature provides good conversion but still leaves some sugars that the brewing yeast won’t be able to consume. Do not over-sparge—use rice hulls and take the lautering nice and slow.
Most of my beers are finishing between 14.5–16.5°P (1.059–1.068). I would honestly like them to finish closer to 13°P (1.053), but the yeast has a hard time holding on past 16°P.
If I am double-batching into a fermentation vessel, on my first batch, I will keep the extra sugar additions to a minimum and keep the gravity a bit lower than my target. The second batch will get more sugar and be a bit higher than my target. The idea is that I am presenting the yeast with a slightly more hospitable environment for the first 24 hours. Then I hit them with the big batch.
I usually start the fermentation at 68°F (20°C) for the first three days, bump up to 72°F (22°C) on Day 4, then free rise. I want to keep the yeast moving and in suspension as long as possible.
Something I will be doing soon with some batches is fermenting in brite tanks. I’m hoping the added surface area of the dish bottom and the reduced hydrostatic pressure will give the yeast more room to do their job. I’m excited to see those results!