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The idea of brewing a Belgian Imperial Porter was something that we had discussed a few times in the past few years, especially after taste panel sessions that had included Belgian Imperial Stouts and Belgian Black beers. Roasted malts and the spicy, fruity flavors from Belgian yeast strains combine surprisingly well, provided proper balance is maintained in the recipe. And we thought an Imperial Porter, with an intense chocolate malt character, might be a fun, and a bit different, version of a Belgian dark ale to try.
With the Stone 09.09.09 Vertical Epic Ale, we were also able to incorporate some ingredients and techniques that we had been exploring a bit with our pilot system and small batch special creation program, such as the use of vanilla beans, tangerine peel, and the French oak chip aging process.
The vanilla bean (used at a lower addition rate than what we use in the Stone Smoked Porter with Vanilla Bean) complements and actually enhances the chocolate flavors from the chocolate malt, and likewise, the French oak enhances the sensation of vanilla. Combined together with the other ingredients, the result is a multifaceted, delicious beer with several layers of depth and flavor.
We hope you enjoy our latest beer (our 8th in the Vertical Epic series), and have as much fun brewing it as we did.
Here is the grain bill:
Pale Malt 73.1%
75-80°L Crystal Malt 10.4%
Chocolate Malt 5.4%
Belgian Aromatic Malt 4.3%
Dark Candi Sugar 3.4% (added to boil)
Black Malt 1.7%
Carafa Malt 1.7%
Again, I am only providing the all grain version of the recipe. I’ve never brewed with extracts, so I’m not the best person to attempt to convert this recipe to an extract one. If someone wants that information, I’d recommend consulting a local homebrew shop or a homebrewing web site or forum to get help in making the conversion.
The goal with this grain bill was to make a complex porter, but without so much dark malt that the yeast and spice flavors would get overwhelmed. In addition, we wanted the chocolate malt to be the dominant dark malt flavor, so we only used a low percentage of black malt, and added small amounts of dark candi sugar and Carafa malt to get some color and flavor complexity without overwhelming the chocolate notes.
Target OG: 20°P (1.080 SG).
Use a 45 minute conversion rest at 150°F. This helps provide a fairly fermentable wort. Lower temperatures and a longer conversion time rests help accentuate dryness of beer. With almost 15% crystal and aromatic malt, a conversion temperature in the normal porter range of 153-156°F might have made this beer too sweet.
If you can, raise your mash temperature up to 165°F to stop the enzymatic conversion of starches to sugars before lautering. If you cannot do that, cut your conversion rest to 20-30 minutes.
Recirculate your wort gently from the bottom over the top of the mash to deposit the fine particles of malt on the top of the grain and to “set” your bed. Avoid splashing the wort. The wort will be too dark to check clarity easily, so recirculate for 5-15 minutes, depending on your system, before diverting wort flow to your kettle/boiling vessel. If you have a refractometer, check your “first wort” (unsparged wort) gravity, it should be about 22-23°P (1.088-1.092 SG).
Start sparging in the lauter when the wort level is about ½” above the grain bed. Starting earlier will decrease your efficiency, because the water will dilute your first wort. Sparge water should be between 165°F and 170°F to maximize extraction, but avoid going over 170°F or you’ll extract harsh compounds from the malt husks.
Sparge until you hit your target boil volume or until your wort gravity being drawn-off reaches 3°P (1.012 SG), whichever comes first. Don’t lauter past 3°P, because when the sparged wort coming off the lauter is that low in sugar content, you risk extracting tannins and other harsh character from the malt husks.
Here is the hop bill:
4.5 grams per gallon Magnum hop pellets (14% AA)
4.5 grams per gallon Perle hop pellets (10% alpha)
All added at the start of boil. No other hop additions (this is a Belgian inspired beer, after all).
We typically boil our wort for 90 minutes. This is a good amount of time to get about 8-10% evaporation. During the boil, it’s good to:
- Add hops at the start. This will help knock down foam and maximize bitterness extraction. Depending on your boil parameters, you may want or need to add some portion of the hops before the boil actually starts to keep the foaming under control.
- Keep the boil rolling at a good clip. Don’t simmer, or you won’t volatilize Dimethyl Sulfide, a malt compound formed at temperatures above 180°F. Dimethyl Sulfide (DMS) tastes exactly like canned creamed corn, you’ll know this flavor when you taste it! A good rolling boil also ensures proper color and flavor development, good hop extraction, and proper trub formation. The rolling boil also helps prevent scorching of the wort where the heat source is at its most intense.
- Add the dark candi sugar. Pour it in after the boil starts or the sugar can settle on the bottom of the kettle and scorch as the heat increases. Burnt sugar is not a desirable beer flavor.
6 grams per gallon dried tangerine peel
0.5 grams per gallon vanilla bean.
We add the spices after the wort boil is complete to maximize flavor extraction. Adding them during the boil may result in many of the flavors being volatilized and lost with the steam. To prep the vanilla bean, slit the bean lengthwise, and scrape out the “meat” from the skin, and then chop the skins. Use all of the bean, skin included, to steep in the wort. For our brews we used a filter bag to hold the vanilla and the tangerine peel.
A note on vanilla beans:
Although there are many varieties of vanilla beans, in general, Bourbon and Tahitian vanilla beans are mostly used in food production. Bourbon vanilla beans are also commonly known as Madagascar vanilla beans because that is where most of them are grown, although the species apparently originated from Mexico. Bourbon beans are long and slender, have a creamy, strong vanilla flavor. Tahitian Vanilla Beans are plumper, shorter, and have a fruitier flavor. The flavors are different, so it’s fun to run trials with different beans. We used Madagascar (Bourbon) vanilla beans in the Stone 09.09.09 Vertical Epic Ale.
Regarding vanilla extract and vanilla flavor: Most vanilla flavorings are not created from vanilla beans, they are extracted from wood! Be careful if you want to use vanilla extract or flavor instead of whole vanilla beans in your beer. Make sure it is natural vanilla extracted from vanilla beans, not an artificial extract or flavor. And actually, vanilla beans are easy to find and use, so there’s no reason not to use real beans in your brew.
During the whirlpool step, the wort needs to be circulated to create a whirlpool. This will cause the proteinaceous trub flocs formed during the kettle boil to be pushed to the side of the vessel. Gravity will then take hold, the flocs will slide down the side of the vessel, and once they reach bottom, will gather in the center to form the trub pile. This is called “the Interrupted Centrifuge Principle”. If you stir tea leaves in a cup of tea you will see the same effect. A good, cohesive trub pile is necessary to decant clear wort to your fermentor and avoid protein carryover, which otherwise could negatively impact flavor, or blind yeast cell walls and impair yeast growth and fermentation.
Yeast Addition: Pitch a Belgian yeast strain, enough to get 20-25 million cells per milliliter (requires a starter)
After the trub has been separated from the wort, chill the wort using an immersion chiller or a heat exchanger to about 65-70°F. Add enough yeast to get a cell count of about 20-25 million cells per milliliter. We used a fairly high pitching rate (yeast addition rate) here, because we wanted to ferment at a lower temperature but still ensure the beer fermented out completely. This means that you will most likely have to build up your yeast culture at home using a starter. Otherwise, you may end up with a low pitching rate, which could results in a stuck/stalled fermentation. If your fermentation does stall out rousing (agitating the tank) to re-suspend the yeast is the best and easiest option. Adding more fermenting wort is the 2nd best option, adding new yeast is a last resort move.
We fermented the Stone 09.09.09 Vertical Epic Ale at 72°F to maximize fruity ester formation and reduce the clove/spicy flavor formations, which form at higher levels with warmer Belgian yeast fermentation temperatures (above 75°F). Again, we were concerned that too much clove flavor would clash with the other flavors in the beer.
The yeast we used in this beer was the Wyeast 3522 Ardennes strain. This yeast benefits from a high oxygenation rate, and will form a very thick krauesen head during the fermentation. It’s a nice yeast that produces a lot of fruit flavor.
The beer should ferment down close to 4°P (1.016 SG).
French Oak Chips: 4.5 grams per gallon
During aging, chill the beer down to about 35°F or so, and let it sit until the beer clarifies. This is the step where the French Oak chips are added. Place the chips in a filter bag with a small piece of stainless to weigh it down and keep it from floating. Sterilize the entire bag and contents by pouring hot (over 185°F) water over the bag and letting it sit submerged for 15 minutes. Then hang the bag in your fermentor until the whole bag is submerged. Start tasting your beer after 3 days and age as long as needed after that to get the intensity of French oak flavor you want.
A Note on Oak Chips:
American Oak is white oak sourced primarily form the Midwest and Upper South states like Missouri, Ohio, Kentucky, and Virginia. In general, most people agree that American Oak has a more aggressive flavor with higher levels of vanillin, increased sweetness and stronger fruit flavors than French grown oak.
French Oak, which is grown in distinct regions such as Limousin, Nevers, Tracair, and Alliers, contributes a more “elegant” flavor that is a bit more delicate, and some feel makes for better long-term aging. The flavors contributed include vanillin, coconut, and clove spice. The regional differences are due primarily to the grain profiles and composition of the wood, although growing conditions, soil makeup, and toast levels of the wood can impact the flavors tremendously.
Here at Stone Brewing Co., we use American Oak in the OAKED Arrogant Bastard Ale, but in the Stone 09.09.09 Vertical Epic Ale, with its subtle spice and hop flavors, we decided to go with French Oak with a medium toast. We feel the flavors combine superbly with the Chocolate malt and the Madagascar vanilla bean.
Package the beer as normal. The Stone 09.09.09 Vertical Epic Ale is wonderful fresh, but with its malt backbone and the added complexities of the oak, vanilla bean and tangerine, it is well suited for aging to 12.12.12, or even beyond. Enjoy your brew, and don’t forget to send us some samples!