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Castle Danger Brewery

Dear Replicator,
A neighbor returned this summer from a vacation on the North Shore of Lake Superior, raving about Nordic, brewed by Castle Danger Brewery. She challenged me to find a way to brew something like it. I was unable to readily find a clone recipe, but I did learn that the beer is a modern interpretation of a traditional Finnish beer called sahti, what some say is the world’s oldest, continually brewed beer style. Having long ago spent a summer in Finland as a high school exchange student, I am now even more interested in taking up my neighbor’s challenge. Might you be able to provide a recipe for this special beer?

Jeff Dahlseid
Saint Peter, Minnesota

A historical style of beer, sahti originates from the northern Baltic Sea region, most specifically Finland. Made with adjuncts such as rye, a unique characteristic of sahti is its use of juniper. A farmhouse-style beer with a lot of flexibility, Castle Danger Brewery of northern Minnesota has created a modern interpretation of this historical style.

Based in Two Harbors, Minnesota, about half-an-hour drive northeast of the port city of Duluth on the North Shore of Lake Superior, the ten-year-old brewery produces both volume and specialty beers for its locals and visitors to the area. And if you’re wondering about the name of the brewery, it’s actually the name of the next town north along the shore.

Castle Danger’s Head Brewer, Bjorn Erickson, provides his own insight on the style and how he and his brewery have interpreted it in the modern age of production brewing.

“Traditional sahti can be all over the board as a farmhouse style of beer, brewed with whatever crops were local and available,” said Erickson. “We’re inspired by that and we translated it into a recipe that satisfies our customers, which, in northern Minnesota, has a high concentration of Scandinavians. I consider sahti to fall somewhere between Eastern European kvaas and Norwegian kveik farmhouse ales in terms of style.”
“We pride ourselves in being a nimble craft brewery that creates a lot of fun, interesting beer styles, being innovative and traditional at the same time,” said Erickson. “We focus on making good beer, giving people what we call the ‘North Shore experience.’”

Traditional sahti and Castle Danger’s take on the style have some things in common, but they are not exactly a match. Erickson does employ modern processes and ingredients in his rendition. Traditionally, sahti was a cloudy, unfiltered beer, brewed with juniper branches that provide the beer’s bitterness. Little or no boil would have made the use of hops virtually pointless and since yeast hadn’t yet been identified, alcohol was created through spontaneous fermentation. Also, being a traditional style, carbonation would have been low to non-perceptible, similar to a cask ale.
In many examples brewed in Finland today, Finnish baker’s yeast is used, similar to hefeweizen yeast in character, producing a banana and clove-like aroma and flavor.

The BJCP (Beer Judge Certification Program) guidelines confirm the banana and clove essence as a signature of the style but also show how wide ranging the style can be. The guidelines state, “The beer’s color can be anywhere from pale yellow to dark brown.” While color is mostly open to the interpretation of the brewer, the beer should be malt-forward with a sweet and/or spicy rye character, with a present, but subtle, pine aroma from the juniper. Carbonation is typically low and the mouthfeel can be thick and tacky. The beer should pack a punch (7–11% ABV) with alcohol warmth expected. Hop flavor and bitterness should be minimal.

Nordic Sahti

At Castle Danger, Nordic, the brewery’s interpretation of sahti, is a medium amber-colored beer that belies tradition with its white foamy head. Hand-crushed juniper berries are used in place of the branches, and placed in the hopback. A hefty dosing of flaked rye alongside a base of Pilsner malt provides a spicy character, while additions of light crystal and honey malt add sweetness and body.

Noble hops (Saaz and Hallertau) augment the subtle bitterness of the berries and help balance the malt sweetness. The juniper berries provide a distinctive piney aroma and a resinous mouthfeel, less woody tasting compared to when juniper branches are used. Rice hulls can be employed by brewers to help prevent a stuck mash from the sticky rye wort, and a small dose of acidulated malt can be added to keep the mash pH in the proper range.

Castle Danger defies tradition when it comes to its use of yeast and level of carbonation in its sahti.

“We actually use a California common strain of yeast,” said Erickson. “It’s a warm-fermenting lager yeast. We carbonate Nordic to about 2.6 volumes of carbonation because that’s what most local craft beer drinkers expect.”
Sahti is a very diverse beer that pairs well with rich foods. Try it along with charcuterie or antipasto. Smoked meats, rye bread with herbed cheese, pickled herring, and other robust dishes also pair well. Serve in a tulip or snifter glass at 40–45 °F (4–7 °C).

CASTLE DANGER BREWERY’S NORDIC SAHTI CLONE

(5 gallons/19 L, all-grain)
OG = 1.053 FG = 1.011
IBU = 26 SRM = 7 ABV = 5.5%

Ingredients
8 lbs. (3.6 kg) Pilsen malt
1.25 lbs. (567 g) Briess caramel malt (10 °L)
1 lb. (454 g) flaked rye
0.75 lb. (340 g) honey malt
1.5 oz. (43 g) dried juniper berries, crushed (20 min.)
5 AAU Saaz hops (60 min.) (2 oz./57 g at 2.5% alpha acids)
7.2 AAU Hallertau hops (10 min.) (1.5 oz./43 g at 4.8% alpha acids)
1 oz. (28 g) Fuggle hops (0 min.)
Wyeast 2112 (California Lager), White Labs WLP810 (San Francisco Lager), or Mangrove Jack’s M54 (California Lager) yeast
¾ cup corn sugar (if priming)

Step by Step
Mill your malts but leave rye flakes whole. Strike-in with approximately 3.5 gallons (13.25 L) of water to achieve a single infusion mash rest at 152 °F (67 °C). A softer water profile works well, but adjust your water as needed and aim at mash pH around 5.3 for best results. It’s OK to mash a little thinner than this if desired, especially with the rye flakes and rice hulls if you choose to use them. Mash for 60 minutes or until converted. Vorlauf until clear and then begin transfer into brew kettle.

With kettle full, take a pre-boil gravity reading. Boil for 60 minutes. It’s OK to boil longer if you want more color and flavor development, if you prefer to concentrate your wort, or want to ensure elimination of potential DMS (dimethyl sulfide) from the Pilsner malt. Add bittering hops at the 60-minute mark. With 20 minutes left add crushed juniper berries. Keep them in a bag to make removal easier. Add remaining hops at 10 minutes and at flameout.

Chill wort to 62 °F (16 °C) and transfer to your sanitized fermenter. Oxygenate at a moderate rate if using liquid yeast strain, then pitch the yeast. Ferment at 62 °F (16 °C). Primary fermentation can take 5–12 days depending on several variables. The key is to be patient. The beer should finish around 1.010–1.011. Rack to secondary if desired or let sit for about one week after primary fermentation is complete then proceed to keg or bottle condition. Carbonate the beer to 2.6 volumes of CO2.

CASTLE DANGER BREWERY’S NORDIC SAHTI CLONE

(5 gallons/19 L, partial mash)
OG = 1.053 FG = 1.011
IBU = 26 SRM = 7 ABV = 5.5%

Ingredients
3.75 lbs. (1.7 kg) Pilsen dried malt extract
1 lb. (454 g) Pilsner malt
1.25 lbs. (567 g) Briess caramel malt (10 °L)
1 lb. (454 g) flaked rye
0.75 lb. (340 g) honey malt
1.5 oz. (43 g) dried juniper berries, crushed (20 min.)
5 AAU Saaz hops (60 min.) (2 oz./57 g at 2.5% alpha acids)
7.2 AAU Hallertau hops (10 min.) (1.5 oz./43 g at 4.8% alpha acids)
1 oz. (28 g) Fuggle hops (0 min.)
Wyeast 2112 (California Lager), White Labs WLP810 (San Francisco Lager), or Mangrove Jack’s M54 (California Lager) yeast
¾ cup corn sugar (if priming)

Step by Step
Flaked grains have no diastatic power, so they cannot self-convert, but they have fermentable sugars if converted. They need to be mashed with a base malt in order to be converted, so we will use 1 lb. (454 g) of Pilsner base malt to help convert the flaked rye and the honey malt. (The caramel malt is already pre-converted to sugar.) The rest of the base malt will come from dried malt extract.

Using about 2 gallons (7.57 L) of water, achieve a single infusion mash rest at 152 °F (67 °C). Insert the grains inside a mesh bag for easy removal later. Mash for 60 minutes or until converted. Remove the grain bag, allowing the liquid to drain out. Raise wort temperature to near boiling, then remove pot from heat and slowly stir in about half of your extract until thoroughly dissolved. Holding back about half of the extract allows your hop extraction to better replicate that of the all-grain version. Return to heat source and raise to boil. Boil for 60 minutes.

Add bittering hops at the beginning of the boil. With 20 minutes left add crushed juniper berries. Keep them in a hop bag to make removal easier. Add remaining hops at 10 minutes and at flameout. Add remaining extract with about five minutes remaining in the boil to properly dissolve the sugars and sanitize the extracts.

Pre-boil and chill about 3.5 gallons (9.5 L) of water separately so you can add that to the wort later. Best to do this before your brew to make life easier.

Follow the all-grain recipe’s step-by-step for remaining fermentation and packaging instructions.

Tips For Success:
If you are looking to brew a more historical version of the style, consider using a hefeweizen yeast strain that will provide the signature banana and clove character. If you want to replicate Castle Danger’s Nordic as closely as possible, then employ a California common yeast.

According to Brewmaster Bjorn Erickson, “The fun thing about this kind of brew is you can feel free to change things up without being untrue to the style. If you are feeling bold, try using more rye, or add some Weyermann Cararye® for more color and depth to the rye flavor. Your mileage will vary with the juniper berries, especially depending on how much you can crush them and what state they are in. ‘Dry hopping’ with juniper berries can add more of the piney/menthol notes. An ounce or two (30–60 g) of lemon zest or caraway seeds can also punch up the aroma.” Don’t be afraid to play around with this one!

Issue: November 2021