He wrote: "Of the various substances which have been shown to be rich in vitamines, brewer's yeast is probably, at present, the cheapest." That's because it was often obtained directly from a brewery in those days — a waste product that otherwise would be washed down the sewer.
This discovery went largely unnoticed among consumers for a few decades until two brothers, Charles and Max Fleischmann, decided they needed to find a way to sell more yeast. The brothers founded Fleischmann's Yeast Co., in Ohio, creating the first commercial yeast in the United States. The yeast came in the form of pressed cakes, wrapped in tinfoil, and sold door to door from distribution centers throughout the country.
By 1920, the yeast business wasn't doing so well, thanks to the availability of store-bought bread, writes Catherine Price, elaborating on a story from her book Vitamania. Fleischmann's enlisted a physician to study yeast and hired famed New York advertising agency J. Walter Thompson to publicize any health benefits. This became known as the "Yeast for Health" campaign, and from 1917 to 1924, the company's sales tripled, says Rick Oleshak, Fleischmann's vice president of marketing.
By 1927, Americans ate 2.45 pounds of yeast per capita. One advertisement declared boldly, "Now you'll like yeast!" and recommended mashing a yeast cake into a glass and mixing it with tomato juice, milk or water. Other ads proclaimed that yeast cakes could cure acne and the common cold and stop constipation. In the 1930s, Fleischmann's launched "XR Yeast," which came with extra vitamins. By 1935, Price writes, the company's advertisements claimed that yeast was even better for your gut health than fruits and vegetables. This was years after the Federal Trade Commission sent its first cease and desist letter for misleading claims.
Though it's hard to know how many people continued mixing their daily yeast cakes into orange juice, the heyday of yeast advertising was over. In 1950, inactive (meaning the yeast was no longer living), dried nutritional yeast flakes hit the shelves in the form of Red Star yeast.
"It was popular during the hippie time in the late '60s or 1970s," says Adeline Cheong, a senior business manager at Lessafre, a French yeast manufacturer that owns the Red Star brand today. The nutritional content was the main draw, and the rising popularity of plant-based diets helped give anything that could provide vitamins like B12 an extra push.
In the 1980s, a rash of books about the candida yeast, which causes fungal infections like diaper rash, hit the shelves. "It was really bad," Cheong says, though she notes that candida and Saccharomyces cerevisiae are completely different. "Just like nowadays you hear about good bacteria and bad bacteria," Cheong says, "[baker's yeast] is the good yeast." But it drove sales and popularity down, and rather than going on a marketing offensive, the company continued quietly making nutritional yeast for its loyal customers. "Nobody thought there was a second wave coming," Cheong says.
Saccharomyces cerevisiae may not have the near-magic powers ascribed to it during the "Yeast for Health" campaign, but people have developed a taste for it nonetheless. "Don't forget, vegans aren't just eating yeast flakes," says James Parker, Fleischmann's vice president of yeast innovation. "Some will go buy active dry yeast and ingest the live cultures." They have no way to track how many people are doing this, but have logged comments from customers on their website speaking to the trend.
Dry yeast flakes, yeast cakes and active dry yeast have wildly different flavors, which has to do not only with additives like potato starch that help yeast reach its final form, but also water content. "Yeast cakes are still about 65 percent water," Parker says. "It creates a difference in strength of taste, mouthfeel, everything." They also have a shorter shelf life than dried nutritional yeast. Despite coming from the same fungus, not all baker's yeast is the same.
"Having tried both of them," Price wrote in an email, "the primary difference that I've noticed is that one is absolutely disgusting (the cakes) and the other has an umami flavor reminiscent of cheese." She adds, "I would never want to eat a yeast cake again."
Tove K. Danovich is a journalist based in Portland, Ore.
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