“I went swimming this morning,” announced Chef Stefan Richter to a rapt audience at a cooking demonstration at the Boathouse in Edgartown on Saturday. “I swam across the harbor. I came back and my toes were blue. No wet suit. It took me about 35 minutes to defrost, it was brutal.”

“It must be that Finnish blood,” an audience member offered.

“No, I think it was the scotch.”

Mr. Richter, a finalist in Bravo’s Top Chef season five and owner of Stefan’s at LA Farm in Santa Monica, enjoyed an eventful weekend headlining the Martha’s Vineyard Food and Wine Festival and entertaining Islanders with the trademark saltiness he exemplified in his television career.

Mr. Richter found talent in the high school's culinary arts program. — Mark Alan Lovewell

Mr. Richter’s whirlwind weekend started with an appearance at the regional high school Friday morning where he taught students in the culinary arts program.

“There’s some talent there,” he said.

On Saturday he participated in a series of cooking demonstrations and receptions in his honor, and, of course, his morning paddle (sans wetsuit) to Chappaquiddick and back (he has video documentation of the event that he is eager to provide to skeptical bystanders).

His patriotic message of the weekend: buy local.

“Our ancestors moved here for a reason,” said Mr. Richter who was born in Finland and raised in Germany. “To better our lives. They came to America to be in America, now we ship wines from Italy, what’s the point? There’s nothing I miss from Europe. I could care less. Why would I ship in baby carrots, when there’s beautiful local produce here, what’s the point?”

He exhorted his audience at the cooking demonstration not to buy berries anymore (“They’re all gone, what’s the point?”), and to use seasonal products in their autumn dishes, particularly root vegetables, like turnips, carrots and parsnips as well as brussels sprouts, leeks, onions and the German favorite, kohlrabi.

For nervous Thanksgiving chefs Mr. Richter insisted that less was more:

“Don’t make 25 dishes. Make three or four and make them well. Your grandma’s Thanksgiving dinner is mediocre. She starts prepping two weeks prior, running around the house, stuffing the fridge — that’s why I never eat at other people’s houses.”

Mr. Richter was also eager to opine on virtually everything else in the world of celebrity chefdom: of television culinary personality Bobby Flay, “I would love to take him down;” of this season’s Top Chef crop, “Kevin’s going to take it home.”

Reflecting on his own experience on Top Chef, Mr. Richter says it may have affected business but it has not affected the man.

“Is it easier to fill the restaurant? Yes. I haven’t changed though. I’m exactly how I was on the show. Honest and straightforward. No [expletive deleted].”

Mr. Richter says he still keeps in touch with last season’s winner, Hosea, despite what he claims was a fictional rivalry that producers invented in the cutting room.

“Hosea’s a great guy. It’s called editing; they’re very good at it. Just look at what they tried to do to me: they tried to make me the villain! It didn’t work. People said I was cocky. People said I was cocky!” exclaimed Mr. Richter, who owns a clothing line called Cocky Chef. He continued:

“I wasn’t a villain. I wasn’t an [expletive deleted]. I told it how it was. I’m too old to [expletive deleted] around, I’m done with it, enough of the [expletive deleted], there’s no reason, what’s the point?”

For a brief moment on Saturday the irrepressible “Chefan” paused to take a breath, as the view from the second story of the Boathouse caught his eye:

“Look at how beautiful this is,” he said, gesturing to the Edgartown Harbor. “There’s no culture in L.A. Look at these buildings here. In L.A. they’re all built for earthquakes, they’re ugly.”

His eye lingered on the view for a moment longer.

“I’m hoping that the boats can’t run tomorrow or my flight is cancelled. I want a reason to stay.”