A case can be made for calling the Woodstock Music and Art Fair, which happened 40 years ago this weekend (August 15-17, 1969), the defining event of the hippie generation. An even better case can be made that granola, which was popularized at the festival, is the defining hippie food—literally. Can you think of another food so associated with a demographic or ethos that it has become an adjective? Just the other day I heard it used by someone who apparently wasn't hip to the whole locavore idea: "Growing your own basil is too granola for me."

There's been a lot of talk in the last week or so about how amazing it was to have so many great musicians on the same bill, to have so many people with more or less the same ideals converge on one place, the insane amount of mud. But what about one of the most mind-boggling aspects of the event: how did they feed close to half a million people for three days, especially when they were expecting only half that many?

In The Road to Woodstock, a new book by one of the festival organizers, Michael Lang, the author recalls, "We originally thought locating a food vendor would be a no-brainer and that this would be a big profit center for us. As it turned out, the large food-vending companies like Restaurant Associates, which handled ball parks and arenas, didn't want to take on Woodstock. No one had ever handled food services for an event this size. They didn't want to put in the investment capital necessary to supply such a huge amount of food, on-site kitchens, and personnel, plus transport everything upstate. And what if we didn't draw the crowds we projected?"

For a while it looked like Nathan's hot dogs—the famous Coney Island vendor—would provide concessions, but there were disagreements over staffing and wages. When the original festival location near the town of Woodstock, New York, fell through and the site was moved to Sullivan County, Nathan's pulled out altogether.

Finally, the organizers hired a trio—Charles Baxter, Jeffrey Joerger and Lee Howard—with little experience in the food business, who called themselves Food for Love. With only two weeks left until the concert, they had no other choice. The day before the festival, Joerger and one of the organizers, Peter Goodrich, got into a fistfight over the deal and the fact that the concession stands weren't finished yet.

As it turned out, the problem wasn't over-projection of the audience but vast under-projection. The initial estimate of 200,000, which was already an unprecedented and incredible number, turned out to be at least 400,000 (the exact number is impossible to calculate, since the idea of tickets and an orderly entrance went out the window before the event even started).

The Food for Love concessions were quickly overwhelmed. Lines were long, and with dwindling supplies they decided to jack up the prices, Lang writes—charging $1 for hot dogs when the going rate was a quarter. On Saturday night, people angry about the wait and the prices burned down two of the concession stands.

On Sunday morning the clown and Merry Prankster Hugh Powell Romney (now better known as Wavy Gravy) tried to defuse the situation, announcing to the crowd, "There's a guy up there—some hamburger guy—that had his stand burned down last night. But he's still got a little stuff left, and for you people that still believe capitalism isn't that weird, you might help him out and buy a couple hamburgers."

The people of Sullivan County, hearing reports of food shortages, gathered thousands of food donations to be airlifted to the site, including about 10,000 sandwiches, water, fruit and canned goods.

Romney's group, the Hog Farm Collective, who had been hired to help with security and other behind-the-scenes jobs, also stepped in to alleviate the food shortage, supplementing the concessions with free food lines serving brown rice and vegetables and, more famously, granola. Romney announced to the crowd, "What we have in mind is breakfast in bed for four hundred thousand! Now it's gonna be good food and we're going to get it to you. We're all feedin' each other."

According to Lang, some people who didn't want to lose their place near the stage hadn't eaten for two days. Powell Romney helped work out a plan to pass out thousands of cups of granola from near the stage area.

With that, food history was made. But perhaps Romney's most important culinary contribution is much more recent: he was the inspiration for the Ben & Jerry's ice cream flavor Wavy Gravy, which was introduced in 1993 and discontinued in 2003.