Tuesday, December 4, 2012

Foraging for Wild Yeast

The fixin's for our sourdough starter include flour, water, a handful of berries covered with wild yeast, and a glass container... Photo: Richard Jamison, Mother Earth News

On one of the daily foraging hikes, a member of the group (who was a biochemist, budding botanist, and well-versed historian, to boot) picked a handful of autumn-ripe Oregon grape berries and explained that the white powder covering the fruit was actually an atmospheric fungus ... more commonly known as yeast!

Wild yeast spores are, he went on to tell us, practically everywhere, and—if they happen to land where there's moisture, sugar, and warm temperatures—the delicate plants will begin to grow and multiply. (Given ideal conditions, yeast can increase its own volume by more than ten times, overnight!)

The airborne microflora are especially attracted to the sweet skin of berries and grapes. They first appear as a whitish powder, but when the membrane of the ripened fruit becomes injured (by pecking birds, perhaps), the yeasty critters slip in and begin to ferment the juice's sugars. (That's why a bowl of overripe fruit—when left in a warm room—will begin to give off a vinous odor.)

Obviously, the fermentation process is no secret ... it was long ago perfected by our ancestors, and produces a number of sought-after beverages today! But—somewhere along the line—an enterprising soul (or perhaps a tipsy Egyptian baker) realized that the same yeast that ferments drinks could, when mixed with dough, be used as a leavening agent.

And after delivering that short lecture, the foraging scientist—who was warming up to the subject—went on to tell us the story of sourdough bread.

Legends about the origin of sourdough bread have, it seems, been almost forgotten. According to the tales, the old-time Californian and Alaskan prospectors guarded their sourdough starter—or "sponge," as they called it—closer than they would a poke of gold. The perpetually fermenting yeast culture was the wellspring of every meal ... and often meant the difference between feasting on fresh bread and choking down a weevil-infested, hard-as-a-rock biscuit.

A homegrown leavening "factory" was made by simply combining equal amounts of flour and water, and then allowing the mixture to sour in an earthenware pot for anywhere from 3 to 6 days ... after which—if the prospector was lucky enough to "catch" some yeast—the dough would become a bubbling mass with a pleasant, slightly alcoholic aroma.

From then on, the "ferment" was kept growing by constant use and subsequent replenishment of the flour and water. A prospector would protect the brewing mass from the below-freezing northern temperatures by wrapping the sourdough crock in his bindle ... and the miners were even known to dangle the earthenware pots in pouches around their necks, and then tuck the fragrant cultures under their long johns to keep the yeasty concoctions alive with body heat. (And, the legends go on to say, if the winter winds howled too fiercely, some gold seekers would hole up in their cabins and slurp down the nectarous liquid—or "hooch"—that formed on the surface of a well-fermented pot of starter. The potent brew would send the trainer on a bender that sometimes went on until the weather cleared!)

My sourdough starter is six years old and lives in this jar in my refrigerator. The liquid on top is called "hooch" and is perfectly normal. -- http://ruralspin.com/2012/01/22/collecting-and-maintaining-wild-yeast-sourdough-starter/

It's no wonder, then, that the sour starter soon lent its peculiar homebrew aroma to a prospector's cabin and clothing ... and to his (or, in rare instances, her) own personal body odor as well, Eventually the starter—and the bread it produced—became so well-known that the gold miners themselves took on the name of "sourdoughs."

Well, most of the folklore that the biochemist related was new to me, but I had read about old-timers collecting the bark of certain trees to gather the dough-doubling plants. It had never occurred to me, however, to forage for yeast myself ... probably because of the ready availability—and low price—of the packeted commercial product, combined with the lack of time to cook with sourdough in today's rushed living pace. But being in the middle of the forest, with plenty of time on my hands (and lots of motivation), I set my sights on producing a batch of wild yeast sourdough.

Read More: http://www.motherearthnews.com/print-article.aspx?id=67394