If you think the beer at your local bar tastes a little stale, spare a thought for the researchers who brewed up a beer from yeast estimated to be 5,000 years old.
The yeast was plucked from pottery used to produce beer in ancient times, extracted from the nanopores of the clay and converted into an alcoholic drink with the help of microbiologists, archaeologists and winery experts. The end result is ostensibly beer that would've been similar to those drunk at the time of the Pharaohs.
The team believes it's the first time that original ancient yeast has been preserved and developed to brew new beer – in this case a 6 percent brew similar to a wheat beer, and a 14 percent mead. Previously, a genetically modified strain of 10,000 year-old wheat was also used to brew beer.
"The greatest wonder here is that the yeast colonies survived within the vessel for thousands of years – just waiting to be excavated and grown," says one of the team, microbiologist Ronen Hazan from the Hebrew University of Jerusalem in Israel.
"This ancient yeast allowed us to create beer that lets us know what ancient Philistine and Egyptian beer tasted like. By the way, the beer isn't bad."
One of the pots that beer was produced from. (Yaniv Berman/Israel Antiquities Authority)
Of course, 5,000 years is a long time for yeast to survive in a nanopore - the team clarifies that these are the direct descendants of the yeast found in the pot, making the yeast strain itself 5,000 years old.
To ensure they weren't confusing them with any yeast strain in the environment, the researchers also tested 27 other vessels which weren't used for alcohol, and 53 other samples around the excavation site, and didn't find the specific nanopore yeast anywhere else.
Beer was hugely important and regularly imbibed in ancient cultures – alcoholic brews like beer and wine were considered safer to drink than water because of the fermentation process, and were also linked to religious practices and health cures.
This particular yeast came from pottery excavated at four different sites across Israel, with the oldest estimated to date from around 3,000 BCE. Based on gene sequencing, the yeast appears similar to those used in traditional African brews, and to modern beer yeast.
"I remember that when we first brought out the beer that we sat around the table and drank," one of the researchers, archaeologist Aren Maeir from Bar-Ilan University in Israel, told AFP.
"And I said either we'll be good or we'll all be dead in five minutes. We lived to tell the story."
The researchers sampling their beer. (Yaniv Berman, Israel Antiquities Authority)
The researchers have even hinted that they might try to get it on sale one day, if you want to drink like the Pharaohs did. The drink did get thumbs up from tasters from the International Beer Judge Certification Program.
The tipple doesn't taste exactly as it would have in ancient times though: only a few of the old yeast strains were extracted, and modern-day ingredients and techniques were used to process it.
Beyond the buzz of drinking 5,000-year-old beer, there is a deeper scientific discovery here: the study shows it is possible to isolate and analyse microorganisms (in this case yeast) from ancient pottery. Up until now, most ancient organism analysis has relied on DNA studies.
When it comes to recreating the past and understanding how our ancient ancestors lived their lives – beer and all – that's an important development.
"Aside from the gimmick of drinking beer from the time of King Pharaoh, this research is extremely important to the field of experimental archaeology – a field that seeks to reconstruct the past," says Hazan.
"Our research offers new tools to examine ancient methods, and enables us to taste the flavours of the past."
The research has been published in mBio.