Two volunteer taste testers said the first-ever, lab-grown hamburger had a texture "close to meat" but was "not that juicy" and lacked flavor.
Mark Post and his team of scientists at Maastricht University in the Netherlands developed the burger with €250,000 ($330,000) in funding from Google co-founder Sergey Brin.
"Cultured beef" is created by harvesting muscle cells from a living cow. Scientists then feed the cells, which multiply into 20,000 small strands of meat which are combined to form one normal-sized burger.
One biopsy from a living cow could create up to 20,000 tons of cultured beef.
The stem cell burger lacked flavor because it lacked fat. As any chef will tell you: fat equals flavor.
"The absence is the fat, it's a leanness to it, but the bite feels like a conventional hamburger," said journalist and author Josh Schonwald, one of the tasters.
Brin hoped that growing meat in labs could fight world hunger and climate change. The goal was to create "a natural meat product that is both cheaper than farmed meat, indistinguishable in texture and just as tasty."
"I'm optimistic we can really scale by leaps and bounds," said Brin, following the initial taste test.