Cultured meat would have some inherent cost advantages over conventional meat, said Hanna Tuomisto, whose research while at the University of Oxford in England was the basis for the Environmental Science and Technology study. “It’s really about the conversion of feed to meat,” she said. “In cultured meat production it’s much more efficient; only the meat is produced, and not all the other parts.”

Gabor Forgacs, a researcher at the University of Missouri and a founder of Modern Meadow, a start-up company that wants to develop and market cultured meat, is aware of the hurdles as well. “Getting cultured meat to the supermarket is going to be difficult, and controversial,” said Dr. Forgacs, whose approach to cultured meat has some similarities to Dr. Post’s, although he has also developed 3-D bioprinting technologies that might someday be used to create thicker tissues.

Given the difficulties, Modern Meadow is first focusing on creating cultured leather. Its process does not use stem cells but rather skin fibroblasts, specialized cells that produce collagen. “There are a lot of parallels to cultured meat, except that it is a lot less controversial because you’re not going to eat it,” Dr. Forgacs said. “But if we can convince the universe that we can build leather, it will be much easier to convince the universe that we can build meat.”

In his work on cultured meat, Dr. Post uses a type of stem cell called a myosatellite cell, which the body itself uses to repair injured muscle tissue. The cells, which are found in a certain part of muscle tissue, are removed from the cow neck and put in containers with the growth medium. Through much trial and error, the researchers have learned how best to get the cells to grow and divide, doubling repeatedly over about three weeks.

“But we need billions,” said Anon van Essen, the technician in Dr. Post’s lab.

The cells are then poured onto a small dab of gel in a plastic dish. The nutrients in the growth medium are greatly reduced, essentially starving the cells, which forces them to differentiate into muscle cells. “We use the cell’s natural tendency to differentiate,” Dr. Post said. “We don’t do any magic.”

Over time the differentiated cells merge to form primitive muscle fibers, called myotubes. “And then they just start to put on protein,” Dr. Post said, and organize themselves into contractile elements. The key to this self-organization, he said, is that the cells are anchored in place (using a technique that he declined to disclose; earlier in his work he used Velcro). “We add anchor points so they can attach to something and start to develop tension,” he said. “That is by far the biggest driver of protein synthesis, and they do that by themselves.”

The result is a tiny strip of tissue, about half an inch long and only a twenty-fifth of an inch in diameter, that looks something like a short pink rice noodle, Dr. Post said.