It was a rough morning. Hung over after a night out in Galway, archaeologist Billy Quinn was nursing a headache over a hearty Irish breakfast, pondering the mysteries of his excavation site and thinking with a measure of self interest about mankind's age-old quest for mind-altering substances.
Then it hit him: His excavation site was a brewery.
The perfectly ordinary site was a flat, grass-covered earth mound known in Gaelic as a fulacht fiadh (full-oct fi-ah). These sites typically have a depression surrounded by a horseshoe crescent of charred stones. Archaeologists have turned up 4,500 so far across Ireland, and more are identified every year. Radiocarbon dating suggests most fulach fiadh were built between 1,500 and 500 BC.
The mounds have been a longstanding riddle. Some experts argue they were for cooking meat: Hot stones would have been used to boil water to cook and preserve the meat. Others say they were prehistoric saunas. Or tanneries, or smithies, or dye-works. The only point of agreement is that water was heated inside.
Quinn and his colleague Declan Moore became convinced their site had a more thirst-quenching purpose: brewing. "It's also possible that the site could have been multi-functional -- sort of a Bronze Age kitchen sink."
But they needed proof. The research was tough, but someone had to do it: Quinn and Moore went on a pilgrimage to places connected with old traditions of brewing. They apprenticed themselves to hobby brewers in the Orkney Islands. In Belgium and Bavaria they learned to brew with hot stones. In Barcelona, they visited a conference on prehistoric brewing, and they traced the roots of beer culture in the Middle East.
Early this summer, they were ready. A crowd gathered in Quinn's backyard in Cordarragh, Ireland. The archaeologists slaughtered a pig -- brewing works up an appetite -- and built a roaring bonfire to heat stones. Nearby they dug a trench and placed a 350-liter wooden trough inside. After two hours, the stones (and the pig) were piping hot. The archaeologists shoveled them into the water until it was a steaming 150 degrees F. Then in went the barley. After 45 minutes of stirring and the occasional addition of another hot stone, they threw in sweet herbs. "To get a pleasant taste we just looked around the garden and picked whatever looked good," Quinn says of his not-so-scientific method. Bayberry and meadowsweet were among the herbs thrown into the mix. Then the brew was poured into 75-liter plastic tubs, some yeast was thrown in, and the beer researchers sat back and waited.
Three days later, the pair cracked open the barrels to reveal a "very tasty, foamy, copper-colored ale," says Quinn. To test the brew, Quinn and Moore threw a party. Guests judged the experiment a success, says Quinn: "People drank it by the liter."
Today, the archaeologists are proud to be called "picobrewers," the designation for brewers whose capacity falls somewhere between home brewing and a microbrewery. Unfortunately, their beginner's luck didn't hold. Each subsequent attempt resulted in a worse-tasting mess. Quinn doesn't blame himself but the ingredients in his garden, which faded and lost their flavor as the summer wore on. "By the fourth try the brew was just a bland cloudy broth," says Quinn.
Now they're waiting until spring, when bayberry and meadowsweet are back in bloom. In the meantime, they're back at their day jobs. 'We're excavating bones again," Quinn says. "It's pretty boring."