News in Science

Ancient yeast reborn in modern beer

A tiny colony of yeast trapped inside a Lebanese weevil covered in ancient Burmese amber for up to 45 million years, has been brought back to life in barrels of beer.

Emeritus Professor Raul Cano of the California Polytechnic State University, originally extracted the yeast a decade ago, along with more than 2000 different kinds of microscopic creatures.

Today, Cano uses the reactivated yeast to brew barrels of pale ale and German wheat beer.

"You can always buy brewing yeast, and your product will be based on the brewmaster's recipes," says Cano. "Our yeast has a double angle: We have yeast no one else has and our own beer recipes."

The beer received good reviews at the Russian River Beer Festival and from other reviewers. The Oakland Tribune beer critic, William Brand, said the beer has "a weird spiciness at the finish," and The Washington Post said the beer was "smooth and spicy."

Part of that taste comes from the yeast's unique metabolism. "The ancient yeast is restricted to a narrow band of carbohydrates, unlike more modern yeasts, which can consume just about any kind of sugar," says Cano.

Eventually the yeast will likely evolve the ability to eat other sugars, which could change the taste of the beer. Cano plans to keep a batch of the original yeast to keep the beer true to form.

If this has a ring of deja vu, it could be because Cano's amber-drilling technique is the same one popularised in the movie Jurassic Park, where scientists extracted ancient dinosaur DNA from the bellies of blood-sucking insects trapped in fossilised tree sap.

Cano's original goal was to find ancient microscopic creatures that might have some kind of medical value, particularly pharmaceutical drugs.

Going to sleep

While that particular avenue of research didn't yield significant results, the larger question of how microscopic creatures survived for millions of years could help scientists understand certain diseases, says Professor Charles Greenblatt, a scientist at Hebrew University in Jerusalem who studies ancient bacteria.

"We've got cases of guys who contracted [tuberculosis] during World War II and lived with it for 60, 70 years," says Greenblatt. "Then suddenly they get another disease, the TB wakes up from its dormancy and kills them."

Inducing dormancy could be a new way to fight disease and infection, says Greenblatt.

Instead of outright killing infectious creatures, doctors could instead put them to sleep. The infection would still be present in the patient's body, but it wouldn't hurt the patient.

Neither Cano nor Greenblatt can say what the upper limit for hibernating yeast or bacteria is - it could be hundreds of million years.

But while other scientists work on that, Cano plans to spend his time tossing back a few cold ones, and hoping others will too.

"We think that people will drink one beer out of curiosity," says Cano. "But if the beer doesn't taste good, no one will drink a second."