Let’s be clear: This is (probably) not a historically accurate recipe, since evidence from the time is scanty. Let’s call it speculation based on what we know of the time and of Scandinavian farmhouse brewing traditions.
King Harald Fairhair’s beer probably was similar to a kornøl, and you can read more about that here (and in my book, Historical Brewing Techniques). So, instead, let’s consider what his subjects might have brewed in the 9th and 10th centuries, during the Viking Age.
The most common malt would have been homemade, from barley dried in a sauna and thus lightly brown and lightly smoked—usually with alder, birch, or juniper wood. Brewing kettles don’t appear to have been commonly available before roughly 1600, so commoners, very likely, would have brewed stone beer. (Huge piles of heat-shattered stone can be found under the soil of pretty much every Norwegian farm, dating anywhere from the sixth century to the early 17th.)
There’s no direct evidence for how the stones were used, but it appears likely that in western Norway, brewers used the stones to heat the brewing liquor then poured it into their mash. In the east, however, they apparently mixed their malt and cold water in wooden vessels, then heated that cold mash with hot stones.
When it comes to herbs, our evidence is limited. There are Middle Age finds of Myrica gale in a brewing context, and from Denmark there are finds going back to the Bronze Age. There’s also evidence for Myrica gale from place names and ethnography, and 900 CE seems early for Norwegian commoners to be using hops. Other possibilities include St. John’s wort, yarrow, and—perhaps the most likely—caraway. Juniper seems almost a given.
With all that in mind, let’s place ourselves in lower Telemark in eastern Norway, during the Viking Age, and imagine something like the following ingredients and process.
ALL-GRAIN
Batch size: 5 gallons (19 liters)
Brewhouse efficiency: 72%
OG: 1.087 (20.9°P)
FG: 1.015 (3.8°P)
IBUs: N/A
ABV: 9.6% ABV
