Drink like an Egyptian: 5,000-year-old yeast resurrected to brew ancient beer

Originally published on June 1, 2019.

This is the golden age for beer lovers. The massive boom in craft brewing means there are more new and exotic suds available than ever before. 

But we can't lose sight of the traditional brews. Not the watery swill that the big international conglomerates sell. Or even the old-world imported brews.

There is beer with real history. Beer that might have had names like Old Persia or Philistine Pale Ale. Or what might have been the original king of beers, consumed by the thirstiest pharaohs of Egypt. 

Beer is very, very ancient — certainly many thousands of years old. But a team of researchers was curious about what three or five thousand-year-old beer tastes like.

Michael Klutstein, a microbiologist from the school of dental medicine at the Hebrew University in Jerusalem, was able to answer that question. In an interview with Bob McDonald on Quirks & Quarks, he explained how he and his colleagues resurrected dormant yeast from 5,000-year-old beer jugs and brewed up a fresh new batch.

• Paper in Microbiology
• AS IT HAPPENS | What does bread from 4,500-year-old Egyptian yeast taste like? Rich, with 'overtones of brown sugar'

Ancient yeast gets a 'wake up' call

After successfully resurrecting yeast from an empty bottle of beer only a couple of years old, Klutstein and his colleagues wondered how far back they could take their experimental process.

Their technique involved using a growth medium comprised of various sugars and liquids to "wake up" dormant yeast by providing nutrients.

The Israel Antiquities Authority provided the team with 21 beer vessels from three different time periods. There were 2,600-year-old beer jugs from a Persian era palace in southern Jerusalem, 3,000-year-old Philistine pots from an archeological dig in Tel Aviv, and vessels from a 5,000-year-old Egyptian brewery near Israel's border with the Gaza Strip.

To the team's delight, they were able to recover yeast from vessels from every time period that had settled in nano-pores in the pottery.

Raising a glass to old times

The team identified a total of six different strains of yeast by sequencing the genome of each specimen. One turned out to be a distant cousin of a strain still used in the brewing process in Ethiopia and Zimbabwe today.

With help from a local craft brewer, the team was able to use five of those strains, along with modern ingredients like hops and barley, to brew fresh beer.

They then held a tasting event, and invited experts from the International Beer Judge Certification Program. The experts' tasting notes included a variety of complex flavours including spicy and fruity, even a hint of green apple in the case of the Persian beer.

The caramel-coloured ale made from the Philistine yeast was Klutstein's personal favourite.

Beer of the protector

Beer is known to have played a very important part of life in places like ancient Egypt. It was associated with great power, had religious significance and was thought to have healing properties. Early Egyptian texts suggest a variety of brews, including "iron beer" and "beer of the protector."

It may also have been healthier to drink beer, because untreated water would have been contaminated with harmful microorganisms that brewing destroys. By some estimates, people drank up to three litres of beer per day.

Now that scientists have figured out how to wake up dormant yeast from so long ago, Klutstein and his colleagues are interested in seeing if they can do the same with other microorganisms from ancient food remains, and recreate other varieties of ancient foods like cheese, wine and pickles.