In search of exciting (and slightly disgusting) yeast news? Well, we’ve got you covered. A biologist from Ecuador was recently able to coax a whole consortium of ancient yeast strains back to life after they’d lain dormant in a hidden deep-welled tomb since A.D. 680.
Pretty cool, huh? That’s not the crazy part.
The resurrected yeast was once used to ferment chicha, an alcoholic watery corn broth popular in pre-Incan civilization. Chicha was commonly placed in the tomb as an offering for the afterlife and after more than a millennium, scientists were able to collect scrapings from deep inside the pores of the clay fermentation vessels.
In a sterile laboratory, they were able to humidify the shriveled cells, repair their damaged membranes, and stimulate their arrested metabolisms enough to revive and study them.
Now here’s the crazy part: none of the yeasts discovered in the tomb were Saccharomyces cerevisiae – the type of yeast used in fermentation today. They were actually previously unknown strains of the genus Candida, the yeast best known for causing skin and vaginal infections.
Prior to this discovery, 16th-century Spanish storytellers had reported that Inca Indians in the Ecuadorian Andes had initiated fermentation using animal bones, human saliva, and even human feces but I don’t think anyone wanted to believe it.
I like an alcoholic beverage as much as the next gal, yet I don’t think I’d ever be sober or thirsty enough to kick back with a drink made with saliva and/or crap. Not crappy ingredients… actual, literal, crap.
Javier Carvajal Barriga, the yeast biologist who discovered this, fermented his own chicha using one of the strains he’d recovered, as he wanted to relive the experience of the prehistoric Indians. He reports, "The flavor was very good. The aroma was very good. The alcohol was relatively good, but the effect was horrible. Just two drinks of this chicha and I had this bad headache typical of aldehydes and esters."
He also noted that chicha needs to be consumed while it is still fermenting because it quickly develops a rancid taste with time – but then if you drink it too early in the fermentation process, you get food poisoning because the bacteria and harmful yeasts have yet to be killed off by the alcohol.
Sounds like a lot of risk for a 3-4 % ABV drink made with spit or poo.
I’d like to thank my good friend Dr. K for passing this information along. I now have a whole new appreciation for all of the yeast options we have today – and I hope you do as well.
If you’re looking for a more geeky, science-centered write-up, just check out this Scientific American article.