From heather to pomegranate, unusual ingredients that were common in beer 1,000 years ago are making their way back into the modern brew kettle, thanks to a quirky new wave of experimentation by small brewers.

Through academic research and consultation of dusty texts, these brewers are producing a stunning variety of unusually flavored ales that were - until recently - virtually extinct.

The oddest, undoubtedly, is Dogfish Head Chicha, brewed this summer with purple maize that founder Sam Calagione and his staff chewed into mush, spit out and dried. The chewing is an essential step in the brewing process, allowing natural ptyalin enzymes in saliva to break down the corn's sugar and convert it into fermentable sugar.

Yes it sounds disgusting, but there's no health hazard because the mush is thoroughly boiled. Hundreds of people lined up at last month's Great American Beer Festival for a taste.

The ancient Peruvian brewing method is still practiced in some South American villages, but it's believed Dogfish Head's is the first commercially brewed chicha in the New World.

Dogfish Head is not the only one dabbling with long-forgotten recipes.

Craigmill Brewing in Scotland specializes in gruit, an old ale style that was prevalent in Europe before the use of hops became universal in the 16th century. Its beers are flavored with pine, blackberries and even seaweed.

At Cambridge Brewing in Massachusetts, brewer Will Meyers makes a Scottish ale flavored with heather flowers; it's a strong drink that Pict warriors might have fortified themselves with 4,000 years ago.

Fossil Fuels Brewing in California reaches back even further with a beer made from yeast extracted from a chunk of 45-million-year-old Burmese amber.

As with most things in beer, this step backward was pioneered by Fritz Maytag and San Francisco's Anchor Brewing, which produced a limited-edition beer called Ninkasi (the Sumerian goddess of beer). The recipe, containing twice-baked bread, dates and honey was based on a hymn found on a tablet dating to 1800 B.C.

The trend should get a boost this autumn with the release of Patrick McGovern's "Uncorking the Past: The Quest for Wine, Beer, and Other Alcoholic Beverages" (University of California Press, $29.95).

It was McGovern, a biomolecular archaeologist at the Penn Museum, whose research of remains from the Turkish tomb of King Midas (8th century BC) led to Dogfish Head's first ancient ale in 1999, Midas Touch. McGovern's chemical analysis determined that vessels found in the burial chamber contained remnants of barley, grapes and honey, revealing a mixture of beer, wine and mead.

Over the years, McGovern has also helped Dogfish Head recreate ancient ales made with Honduran chocolate (the 3,200-year-old Theobroma) and Chinese rice, honey and hawthorn fruit (the 9,000-year-old Chateau Jiahu).

Is there any ingredient man hasn't tried to turn into booze? I asked McGovern.

"That's the story of early mankind," he replied. "Humans figuring out how to chew all kinds of carbohydrates: stems, grains, roots, fruits and honey . . . As humans get into a new environment, they begin exploring the whole environment for what's fermentable, and that's what led to whole slew of beverages around the world."

Booze eventually led man - historically a migrating creature - to settle down, McGovern said.

"Rice, barley, wheat, and corn - the main reason we domesticated it was to get more of it and process it in the best way possible to make a fermented beverage," he said.

Through the ages, as brewing ingredients and techniques were perfected, old varieties like gruit and sahti (made with rye bread) disappeared. Are modern beer drinkers ready for a taste of the past?

Calagione thinks so. "Craft beer drinkers are basically promiscuous," he said. "They're open to anything."

Even, it turns out, spit.

"Joe Sixpack" by Don Russell appears weekly in Big Fat Friday. For more on the beer scene in Philly and beyond, visit www.joesixpack.net. Send e-mail to joesixpack@phillynews.com.