Brewing Ancient Nordic Grog

decorative bottle of dogfish head brewery's kvasir, a nordic grog
Photo courtesy of Dogfish Head Craft Brewery

“I’m lucky I get to do this,” Sam Calagione, Dogfish Head Craft Brewery Owner and Brewmaster states in no uncertain terms when asked about one of his latest “archaeobeer” projects: Kvasir. This 3,500-year-old “Nordic grog,” is the seventh beer in a series of brewing collaborations between Calagione and famed fermented beverage archeologist Dr. Patrick McGovern of the University of Pennsylvania Museum of Archaeology and Anthropology.

“In the late ’90s we started doing some historic beers on our own,” Calagione continues, “which led to our collaboration with Dr. Pat.”

Dr. Pat, as he is oft-referred, is the world’s leading authority on ancient fermented beverages. His exact title is something of a mouthful: Scientific Director of the Biomolecular Archaeology Project for Cuisine, Fermented Beverages, and Health. So for most purposes, Dr. Pat works just fine. Titles aside, McGovern and Calagione have worked together to bring ancient libations back to life since meeting at a Pennsylvania Museum dinner hosted by renowned beer enthusiast and author Michael Jackson in 2000.

During the course of dinner, McGovern announced his intentions to recreate an ancient brew, offering any of the assembled brewers the chance to work with him. Calagione’s approach to brewing made it clear to McGovern that the brewers at Dogfish Head would go to any lengths to recreate these long-lost beverages, which is why their collaborations have continued for more than a decade.

“Sam will put the investment into it even when we don’t know if it’s going to work,” McGovern explains. “He genuinely wants to do something with antiquity and take a chance and experiment. A lot of brewers have passion, but he’s really willing to go much further.”

“When we started brewing beer in 1995 our purpose was, ‘Off-centered ales for off-centered people,’” Calagione says. “The definition of off-centered then is considering the entire culinary landscape for potential beer ingredients, not just the relatively recent beer ingredients of using just water, yeast, hops and barley.”

Together, McGovern and Calagione devised a recipe for Midas Touch, a beer synthesized from organic matter isolated from some of the hundreds of drinking vessels found in King Midas’ 700 B.C. tomb discovered near Ankara, Turkey. The pair also created a recipe for Chateau Jiahu, a combination of rice, honey, wild grapes and hawthorn deduced from the world’s oldest known fermented beverage, unearthed from a Chinese archeological site dating back 9,000 years, and Ta Henket, an Egyptian ale favored by the Pharaohs. A chocolate drink from Honduras, Theobroma, and an Andean chicha have also been recreated.

Where to Start

The process for turning these ancient drinks into modern brews goes back, in some cases, many thousands of years, and typically begins where the life of an important person ends. Burial sites or tombs “offer extremely good preservation” of organic residues perfect for analysis, McGovern says, and were typically filled with various vessels holding libations to help sustain the deceased on his or her journey to the underworld.

McGovern looks for commonly shaped drinking vessels, ones with narrow necks that could be stoppered, but also buckets that could have contained fermented liquids. Within these vessels McGovern looks for “tide lines” — rings around the edges where liquids have evaporated and left residue — but also colors, stains or organic accumulations in the bottom that may indicate some aspect of a beverage has been left behind.

“Even if nothing is visible, sometimes the best organics are what’s absorbed into the vessel,” McGovern adds.

In the case of Kvasir, “mounds” of organic matter resided in the bottom of birch buckets in the oaken burial chamber of an important woman, someone McGovern speculates was a, “priestess or dancer of upper class,” based on items discovered in the tomb, including the grog bucket.

Once identified, McGovern harvests samples, which are then taken to his lab for a chemical breakdown of the molecular and biological components that make up the residues. Using such techniques as infrared spectroscopy, liquid chromatography, and an orbitrap detector, he first begins searching for the usual suspects: “Fingerprint compounds” known to exist in fermented drinks brewed thousands of years ago. Beeswax, for instance, indicates a presence of honey, a common fermentation agent in both wine and beer since the sugars turn to alcohol during fermentation. For beer, McGovern looks for calcium oxalate, which is present in many grains and may indicate the presence of barley. The whitish substance is generally referred to as beer stone.

“You have to have some notion of what you’re looking for,” he says.

With his data, McGovern begins piecing together an ingredient list. Eventually, it will be up to Calagione to determine the proper ratios, but before that happens, ancient ingredients must be sourced in modern times. That’s where Calagione’s “culinary landscape” looms large. Sometimes substitutions have to be made, but the pair have practically gone to the ends of the earth in search of proper ingredients in an attempt to remain as true and accurate to what they believe most represents an original recipe. Together, they have scoured foreign markets for ingredients, harvested wild yeast in date farms and vineyards, gathered quarry dust believed to have inoculated the Egyptian brew, and more.

Developing Kvasir has worked in this same way. While less difficult and extreme in the overall ingredient hunt, Calagione admits, “With this one we had some challenges.” With some of the ingredients being so different from each other, the concern was how to determine the proper ratio. Calagione consulted with Swedish brewery Nynäshamns Ångbryggeri to see how these brewers would handle a local ingredient list they possibly would be familiar with — cranberries, lingonberries, yarrow, bog myrtle, honey, and meadowsweet.

“We thought it would be fun . . . to reach out to a local Swedish craft brewery and see how they would brew with these ingredients,” he adds. “They handled the European test brew.”

The results were not surprising for McGovern, given his historical knowledge. The grog tasted sour from the fruits used in the recipe, something more akin to a Belgian lambic, which, he says, made perfect sense given the northern location where the drink was created 3,500 years ago.

“A lot of our recreated beverages have been on the sweet side, and sweet is not bad, but in this case for the Nordic grog we’re shooting for a more sour beverage, more of a Belgian lambic,” he explains. “The idea was, if you’re in a northern climate you don’t have a lot of sugar resources for fermentation and you take whatever you’ve got and you mix it together, get the fermentation going somehow, and come up with this hybrid mixed beverage or grog that takes you through the cold dark winters. You’re really pushing the limits of the resources you have to make a (sweet) fermented beverage.”

Uncles Sam’s Headaches

Satisfied with the results, scientist and brewer returned to the United States hoping to begin the brewing process on a larger scale. However, new problems presented themselves, namely that two of the three herbs used in the combination of ancient bittering agents better known as gruit — bog myrtle, yarrow and meadowsweet — were disallowed by the US Food and Drug Administration. Yarrow, the government said, contained thujone, a hallucinogenic compound also found in wormwood, which is used to make Absinthe, a banned substance. Consumption of thujone has been regulated for use below 35 milligrams per liter. The amount needed to brew a 50-barrel batch raised the alarm with the FDA, and they needed to get approval.

“It was a long process,” McGovern says, some exasperation in his voice, “but we did get approval.”

Less fortunate were attempts to use meadowsweet, which contains salicylic acid, which is the active component of aspirin — another substance regulated by the FDA. “They said we were making up a medicine,” McGovern says. “We ended up substituting clover. I don’t like the aroma so much for clover as I do meadowsweet,” which, he adds was a typical ingredient in meads.

Given all the unknowns in the brew — alcohol content, exact proportions and ratios, etc., the pair take a few creative liberties in bringing Kvasir into the 21st century.

“Usually we start with the botanical, molecular and historic data that Dr. Pat provides, but that’s really just a laundry list of natural ingredients,” Calagione says. “Modern brewers are given the liberties to decide what the ratios of those ingredients would have been; if the beer would have been filtered, what the alcohol content would have been, if it would have been carbonated. We still have a lot of creative leeway.”

While McGovern’s testing revealed traces of honey — probably used to balance the tartness from the cranberries and lingonberries — that leeway includes the addition of Alaska birch syrup, along with wheat and barley. The latter two add body and color, but all contribute fermentable sugars to drive up the alcohol content for modern tastes while creating a more drinkable product.

“The lingonberries and cranberries add a lot of tart, sour notes. They contribute some fermentable sugars, but not like strawberries or blueberries,” Calagione says. “So we bump up the alcohol with honey and birch syrup in addition to wheat and barley.”

Yeast is also a necessary modern ingredient. McGovern speculates that given the age of the original grog, only wild yeast strains or bacteria would have fermented the beverage as the understanding and use of yeast in brewing and other applications only dates back approximately 800 years to Louis Pasteur. Thus, whatever fermented the beverage left in the bucket designated to help the priestess’ in her journey to the underworld, remains a mystery.

“It’s not as mild tasting as something like Midas Touch,” Calagione adds, “but if somebody likes lambics or (sour) styles, this could be their favorite ancient ale.”

Uncorking McGovern’s Past

McGovern, whose books on the subject of ancient libations include Uncorking the Past: The Quest for Wine, Beer, and Other Alcoholic Beverages, and Ancient Wine: The Search for the Origins of Viniculture, cites his discovery that, “beer was cheaper than Coca-Cola” during a high school trip in Europe as the turning point in his interest in fermented beverages. “We started drinking lots of Bavarian beer,” he says with a light laugh. “That was a formative experience.”

He later worked at a winery in the Mosel region of Germany, before returning to the US and pursuing an archeological career. It was when people brought to McGovern what they thought were beer or wine samples that he, “had a natural inclination to look into it,” he says. “As we got deeper and deeper into this, I was working with other scientists and we just started getting more and more involved in these fermented beverage studies.”

McGovern’s pursuit has included the discovery of the world’s oldest known barley beer (from Iran circa 3400 B.C.), oldest grape wine (also from Iran, circa 5400 B.C. and the oldest fermented beverage of any kind — a grog — unearthed in China, circa 9000 B.C.). Relatively speaking, the Kvasir is not very old, but its ingredient list and sour flavor certainly make it different from most other ancient fermented concoctions.

Bring the Past Home

If early man could brew beer with only the most basic tools and ingredients, the modern homebrewer should have no problem replicating the past.

“Basically, these were early brewers in early civilizations, so their equipment was at least as simple or primitive — more simple and primitive actually — than what modern homebrewers use,” Calagione says.
Those creative liberties mentioned previously also extend to the homebrewer recreating ancient ales.

“What we learned is that almost all these were fermentable hybrid beverages. That is, something between mead, wine, and beer. Grain and honey and fruit,” Calagione says. “These are pretty easy to attack at the homebrew level. You don’t have to be a world-class, all-grain brewer to replicate ancient ale because they have so many more accessible sugars than a simple all-grain version. There are a lot to play with. These ales are a lot of fun to brew at home because you have all these partial mash syrups. They are almost easier to brew in terms of time than traditional all-grain batches. You can steep grain in a bowl with water as a partial grain batch, then add honey or (birch) syrup.”

As noted above, wild yeast most likely fermented the Nordic grog, yet for a modern day application, a clean yeast strain is recommended. To find the best one for this application, Calagione brewed a single batch of Kvasir, then broke it down into smaller proportions and experimented with different yeasts.

“At Dogfish we have pretty sophisticated yeast growing room with seven 1,200-gallon tanks,” he explains. “We have the great latitude in keeping multiple yeast strains active and ready to pitch at any time. So when we run with new recipes we can put them into six or seven small carboys and test how that recipe works with six or seven different yeasts.”

The same process can be accomplished at home with half-gallon (1.9-L) growlers. Brew your ancient ale and rack off into as many growlers as desired. Leave some headspace for the yeast and foam expansion and then pitch several different strains to see which best fits your palate.

Again, Calagione cautions homebrewers to use a clean yeast strain.

“Ancient brewers probably would not have known of wild yeast or bacteria, what they were or if they were present,” he explains. “That’s why we recommend that homebrewers who are using very expensive ingredients like birch syrup and want it to really shine through the brew use a neutral yeast strain so nothing competes with the funky flavors of the wild yeast and bacteria present.”

Future of the Past?

“Back when we started doing the recreations, no one was really familiar with these hybrid beverages,” McGovern says. “Now people perk up their ears and want to know more. People are just fascinated by this idea of ancient beverages.”

So is there something new in the works from some long forgotten time?

“Dr. Pat and I are hard at work at our next ancient ale,” Calagione says.

Can we get a hint of what that might be, the continent it hails from? The tomb it was found in?

“No clue what it is,” Calagione says, keeping the secret to himself. Whatever the ancient fermented beverage, if it’s already been non-existent for hundreds, maybe even thousands of years, then it’s only logical that we can wait a little longer.

label for dogfish head brewery's kvasir, a nordic grog
Image courtesy of Dogfish Head Craft Brewery

Dogfish Head’s Kvasir clone

(5 gallons/19 L, all-grain)
OG = 1.087 FG = 1.011
IBU = 18 SRM = ~23 ABV = 10.4%

7 lbs. (3.2 kg) wheat malt
5.5 lbs. (0.23 kg) Maris Otter malt
0.5 lbs. (0.23 kg) caramel malt (40 °L)
0.3 gallons (1.1 L) preservative free cranberry juice (10 min.)
0.7 lbs. (0.32 kg) birch syrup (10 min.)
2 lbs. (0.9 kg) honey (10 min.)
0.25 oz. (7 g) meadowsweet (5 min.)
0.1 oz. (3 g) yarrow (5 min.)
10 oz. (283 g) Myrica gale (5 min.)
0.6 lbs. (0.27 kg) fresh or frozen lingonberries (0 min.)
0.3 lbs. (0.14 kg) fresh cranberries (0 min.)
~5 drops pectinase enzyme
2.64 AAU Hallertau, Spalt or Tettnang hops (0.6 oz./17 g at 4.4% alpha acids) (60 min.)
0.8 AAU Hallertau, Spalt or Tettnang hops (0.18 oz./5 g at 4.4% alpha acids) (10 min.)
White Labs WLP011 (European Ale) or Wyeast 1087 (Bohemian Ale Blend) yeast

Step by step

24 to 48 hours before brewing: Crush the lingonberries and cranberries in 0.5 gallons (1.9 L) of water and treat with pectinase per the manufacturer’s instructions.

Heat 4.5 gallons (17 L) of water to 166 °F (74 °C). Mash the grains at 153 °F (67 °C) and hold for 60 minutes. After conversion is complete, start the lauter process. Sparge with just enough water to collect about 6 gallons (23 L) of wort in the brew kettle. Total boil time is 90 minutes. At 50 minutes into the boil add the birch syrup, honey, and cranberry juice and the second hop addition. With 5 minute remaining in the boil add the meadowsweet, yarrow, and Myrica gale.

After 60 minutes have elapsed, turn off the heat, add the lingonberry – cranberry mixture. Give the wort a long stir to create a whirlpool and let the mixture sit for 15 minutes. Chill the wort to 62 °F (17 °C) and transfer to a sanitized fermenter. Try to leave most of the fruit behind, there should be about 5 gallons (19 L) of wort in the fermenter. Pitch the yeast. Ferment at 62 °F (17 °C). After primary fermentation has completed, rack to secondary fermenter and mature for at least 21 days. Bottle or keg and enjoy.

Extract with grains option:
Replace all wheat malt and 5 lbs. (2.3 kg) of the Maris Otter pale ale malt with 7 lbs. Bavarian Wheat dried malt extract. Preheat 1.5 gallons (5.7 L) of water to 154 °F (68 °C). Place the caramel and Maris Otter malt in a steeping bag in the water. Steep the grains at 153 °F (67 °C) and hold for 15 minutes. In a second vessel, heat approximately 1 gallon (3.8 L) of water to 175 °F (79 °C) for rinsing. After the steeping time has elapsed, place the steeping bag with malt into a colander and let it drain into the brewpot. Rinse the grains with the 175 °F (79 °C) water and increase the heat. At 200 °F (93 °C) mix in the dried malt extract and raise to a boil. Add the first hop addition at the start of the boil. Boil time is 60 minutes.

Issue: March-April 2014