In a modern oven in Pasadena, Calif., recently, yeast that could be as old as ancient Egypt was used to bake an especially aromatic loaf of sourdough bread.

The baker, Seamus Blackley, was experimenting with yeast he had extracted from a 4,000-year-old Egyptian loaf. He was trying to make his own bread using the same ingredients, and some of the same methods as the ancients.

Blackley — who is also a creator of the Xbox, a physicist and a self-professed “bread nerd” — posted the results on Twitter.

“The crumb is light and airy,” he wrote. “The aroma and flavor are incredible. I’m emotional.”

Thousands of people responded in a surge of interest that extended far beyond niche communities of bread nerds and yeast enthusiasts, whose interests traverse science, gastronomy and history.

Something similar happened in April, when he made a loaf of bread using a yeast strain that was said to be 5,200 years old.

He had not extracted that yeast himself and could not be sure of its exact provenance. But tweeting about the experience helped him connect with others who shared his interests, including Richard Bowman, a biologist at the University of Iowa, and Serena Love, an archaeologist, Egyptologist and honorary research fellow at the University of Queensland in Australia.

Bowman brews beer, and he got in touch with Blackley to talk about yeast. It was Bowman who devised a way for Blackley to extract yeast strains from ancient artifacts without damaging them.

And Love, who also brews beer, managed to get Blackley access to the artifacts from the Museum of Fine Arts in Boston and the Peabody Museum at Harvard.

“I had to submit all sorts of documentation, detail our methods and show that it’s a nondestructive analysis,” she said. “Once they could see that we weren’t harming the vessels, they gave us permission.”

Once they run out of food, yeast spores can go dormant — rather than simply dying — and stay quietly viable for thousands of years until they are extracted, Bowman said.

“I don’t understand why everyone is so interested in this, but I’m happy that they are,” he said. “It gives us an opportunity to demonstrate good science.”