Whenever Chris Frey is ready to brew, he fills thirteen five-gallon jugs with water in Detroit and hauls them back to his home in Saline. “Gretchen [Driskell], our mayor, would not be pleased to hear me say this,” he confesses with a smile. When Frey first moved to Saline thirteen years ago and started brewing beer in his basement, he learned about the high levels of iron in the water the hard way: his home brew had a metallic, almost bloody, taste.

The city has since taken steps to reduce iron in the water, so Frey says he intends to give it another try. For Frey, it was one of many lessons in the art and science of brewing beer.

Craft beer, marked by its unique flavors, quality ingredients, and small-scale production, has experienced a renaissance in the last twenty years. There is a growing commercial market, but Frey is happy to keep brewing a hobby. He’s got beer in his blood–his great-grandfather owned a brewery in Grand Rapids–and, as a glance around his basement confirms, an unabashed passion for making it.

Frey, who works at Ford as a process effectiveness manager, got into brewing via the loosely affiliated Fermental Order of Renaissance Draughtsmen, a brew club composed mostly of Ford workers. “I didn’t have a creative outlet,” he explains. That was fifteen years ago. Now his basement is filled with old bottles, containers of wheat and barley, stacks of recipes, and a fifty-six-gallon barrel currently filled with a Flanders Red, a sour Belgian-style beer.

Belgian ales are often aged for months or years in casks formerly used for fermenting wine or liquor. The tannins and the residual bacteria left over from the fermenting process add rich and complex flavors.

Frey points to a glass of British barley wine–a concoction of the Ann Arbor Brewers Guild, a home-brewing club of which Frey is treasurer. It’s made from grains, not fruit, but it’s called a wine because of its high alcohol content (6-12 percent). The wine, Frey notes, is a living thing. Using what is known as the solera method, the club brewed an original batch, which they draw from and add to as needed–much like a sourdough starter. The resulting brew is a mix of different ages, some of it now nearly four years old. It tastes oaky and tart, with a whisper of bourbon.

At the February meeting of the Chelsea Homebrew Club, Greg Cole passes around a wheat beer he brewed last August. “It’s not poison, but it’s not what I’m looking for,” he says, wondering if there was a problem with the yeast or the water. The dozen participants sniff and sip and hold the beer up to the light. The consensus: great mouth feel, but not enough backbone. Translation: maybe it wasn’t technically a wheat beer, but it wasn’t bad.

The meeting is part history lesson, part chemistry class. The group discusses fermentation temperatures and boiling processes. Chris Felesky asks about planting hops, whose fruit gives beers a tangy, bitter taste. Hops are relatively easy to grow, explains club organizer Chris Martinson of Grass Lake, who is working on plans to open a brewpub in downtown Chelsea. Martinson started a side business in hops a few years ago, when a worldwide shortage drove prices up. Felesky likes the idea of growing his own, even though he might get a more consistent flavor by buying hops: “If I wanted consistent I’d go and buy a six-pack.”

Late last year, Ron Jeffries opened the Jolly Pumpkin Cafe & Brewery in downtown Ann Arbor and began expanding his Jolly Pumpkin Artisan Ales in Dexter. It’s crammed with dozens of oak barrels, pallets filled with bags of wheat and barley and hops, boiling kettles–and boxes of bottles waiting to be shipped. “Michigan: the great beer state!” reads a sticker on a cooler.

“We’ve been growing every year since we opened,” says Jeffries, whose wife and son also work for the company. Between Ann Arbor, Dexter, and another new brewpub in Traverse City, the Jolly Pumpkin made 1,400 thirty-one-gallon barrels last year, twice as many as in 2008.

Many microbreweries don’t ferment their beer in oak casks, but Jeffries does. People travel from all over to taste Jeffries’ concoctions, like the experimental garlic-hot pepper beer he unveiled in late February at the Michigan Brewers Guild’s Winter Beer Festival in Grand Rapids.

“I’ve always joked about using garlic in a beer,” says Jeffries. “It seems like a hard thing to put in a beer.” He also was curious if he could use hot peppers without producing a burning sensation in the throat.

Most of Jolly Pumpkin’s fare is not quite so zany, although the flavors–spicy, sour, caramel, earthy–are a far cry from large-scale, industrial beers. Craft brewing, says Jeffries, is a combination of art, science, and craft. If you don’t understand the science, you can’t make a consistent yet distinct beer. And, like many productions, it requires a lot of repetition: cleaning tanks, checking temperatures, filling bottles. Some of Jeffries’ beers age for years, so making a profit in the craft industry–which commands only 5 percent of the American beer market–requires careful planning and a keen vision. But it helps to have an adventurous imagination.