NORTHPORT, Maine — When Harry Rosenblum was a child, he loved the summers when his family came to Maine and he got to run a little bit wild in the village of Bayside.

He would mess around in tidepools, go down to the beach and fish off the dock. Rosenblum, now a culinary professional with a recently released book, “Vinegar Revival,” recalls catching enough mackerel for his family’s dinner when he was younger than 10. He experimented with unusual ways to cook all that mackerel — curing it to make sushi was a family favorite — and he did his best to make a few dollars selling crabmeat and mackerel to his neighbors. His family shopped at local farm stands, the farmers market and the Belfast Co-op. All those experiences made an impact, he said.

“It very much helped shape who I became,” he said recently on a return trip to his family’s home in Bayside.

Rosenblum, 40, is the co-founder of The Brooklyn Kitchen in Brooklyn, New York, a former kitchen supply store and grocery that now is a cooking school. And just like he was as a boy in Maine, he’s still a curious cook, eager to feast on and learn more about nature’s bounty. That curiosity eventually took him in the direction of vinegar, a substance so commonplace it seems there would be little to learn about it. But that was far from the case, Rosenblum learned.

“I’ve always been a tinkerer. I’ve always been interested to understand the process,” he said. “And vinegar’s so interesting. … For a long time, humans thought fermentation was magic. We had no idea how it was happening.”

For him, the process of learning about vinegar actually began when he was an underage and thirsty college student, eager to drink beer but unable to legally buy it. But he could buy the ingredients to make it himself, and that is how he first got involved with fermentation. After college, he continued his experiments in fermentation when he started to make hard cider in the kitchen of his Brooklyn apartment. Then, one day, he made vinegar after discovering he had fermented more cider than he had bottles to put it in. But he had an empty gallon jug and a bottle of organic white wine vinegar in his pantry that “had grown this odd-looking round raft at the top of the liquid,” Rosenblum wrote in “Vinegar Revival.”

That odd-looking raft was, in fact, what’s called a vinegar “mother,” a slimy mass of cellulose and acetic acid bacteria that develops on fermenting alcoholic liquids. He knew a little about making vinegar, and so added the mother vinegar to his extra cider, put it in the gallon jug and left it alone in a dark room for a few months.

“When I remembered to check on it, I found that the cider had turned to vinegar — and it was delicious,” he wrote. “In fact, it tasted better than the cider I had started with.”

Rosenblum, motivated to keep on experimenting, tried his hand at making malt vinegar from just-brewed beer, wine vinegars and fruit vinegars. It was a revelation, he said. The homemade vinegars tasted almost nothing like their mass-produced relatives found on supermarket shelves.

“You think of vinegar as a singular flavor,” he said. “But when you start tasting these other vinegars, you can tell the flavor is there. You’re not just smelling and tasting acetic acid.”

Vinegar is good for you, he said, and homemade vinegars can have a lot of trace minerals, enzymes and other compounds.

“Making your own is the true way to ensure that what you’re consuming is, in fact, alive,” he wrote.

And using a well-crafted vinegar can transform the food we eat. A little vinegar can add brightness, lightness and complexity to a dish or transform a quotidien meal into the realm of extraordinary. “Vinegar Revival” tells how to make vinegar from scratch and also gives good ideas about using it. There are recipes for shrubs (a vinegar-based drink that was popular in colonial America), pickled beets, pickled peppers, cured grapes, pickled whole garlic and even pickled, smoked pig’s feet. There are recipes for vinaigrettes, real mustard, salt and vinegar boiled peanuts, sauerbraten, german-style mashed potatoes, squash steamed over vinegar and so much more.

Vinegar keeps things interesting, Rosenblum said.

“It’s totally alive. It’s alive in a way that’s sort of odd,” he said. “And it’s delicious.”