How many will survive the long haul? No one knows. Greenhagen estimates it takes sales of 2,000 to 5,000 barrels a year to become profitable, a number Ipswich Brewery’s Rob Martin, who heads the Massachusetts Brewers Guild, questions. He says it’s more like 10,000 barrels annually before the necessary economies of scale are realized and profitability reliably flows.

In March, meanwhile, the association reported an additional 618 breweries in the planning stages. The association’s Massachusetts chapter, which currently lists 28 members, added at least eight new breweries in the past 18 months, with Wandering Star in Pittsfield and Jack’s Abby being among the latest of the marketplace entries.

This new wave of niche breweries is the most noteworthy since the mid-1990s. Normally, between 100 and 200 breweries start up each year, according to the Colorado-based Brewers Association, an organization representing some 1,760 craft brewers nationally. (A craft brewer is defined as one with an annual production of 6 million barrels or less.) However, the number of craft brewers is up a noteworthy 8 percent since 2009 - and more than 60 percent in the past five years. Sales of existing breweries rose 12 percent in 2010, to $7.6 billion, from the previous year, another measure of these niche brews’ growing popularity.

To beer specialist Andrew Crouch, author of “Great American Craft Beer,’’ New England is merely catching up with California and other parts of the country already experiencing their own craft beer boomlets. “These aren’t accountants looking for a second career,’’ Crouch says. “They’re social-media savvy, entrepreneurially minded people who are willing to take risks - and who tend to brew more eclectic, experimental beers’’ of limited appeal to mass-market tastes.

“It’s almost like the recession caused a wave of Yankee ingenuity,’’ says Bryan Greenhagen, founder of Mystic Brewery in Chelsea, yet another start-up coming online soon. Adds Greenhagen, whose resume includes cofounding an industrial fermentation company: “Everyone is doing a different take on brewing. It’s exciting.’’

Lohring has plenty of company these days. In Framingham, brothers Jack, Eric, and Sam Hendler just produced the first kegs of Jack’s Abby, a line of handcrafted lagers being brewed in a former welding shop. Boston will soon get another home brew of its own, too. Last week, Trillium Brewing Co. was granted a municipal license to begin production at its Congress Street facility, the first step in a process that could have it up and running by early next year.

Lohring is manufacturing and packaging two new beers, Notch Session Ale and Notch Session Pils, using equipment he leases from Ipswich Ale Brewery. Introduced this spring, those beers, which feature a lower-than-usual alcohol content, aim to capitalize on a growing thirst for locally made brews, following a trail blazed a generation ago by brands like Sam Adams and Harpoon and more recently by the likes of Dogfish Head and Stone Brewing Co., regional craft breweries that have built national followings.

“Brand building takes at least a few years,’’ says Martin. “This is a big boys’ business, and in the end you’re working against some of the biggest breweries in the country.’’

But, he adds, this expanding interest in, and demand for, homegrown beers and ales is catnip to local brewers, particularly those skilled enough to take advantage of changing technologies and consumer tastes.

“There’s now a generation or two that’s grown up seeing Sam Adams in their parents’ refrigerators,’’ Martin says. “They don’t have to be educated about fine craft beer. Also, you have the whole locavore movement going, which puts a premium on locally grown and harvested products, wines and beers included.’’

Like the lagers and ales they lovingly produce, these new-generation breweries come in a variety of production models. At the lowest end are the so-called nanobreweries, beer-makers that produce fewer than 100 barrels annually, or roughly two to six kegs per batch. Like Notch, they often rely on bigger bricks-and-mortar breweries to make the beer they formulate, package, and sell. A six-pack of Notch - which keeps its alcohol content below 4.5 percent, while most craft beers run 6 percent and higher - normally retails for about $9, says Lohring.

Idle Hands Craft Ales and Night Shift, both of which will brew in Everett, are among the newest locally owned nanos. Idle Hands owner Christopher Tkach typifies the new breed of New England brewmeister. A 38-year-old software engineer, he is converting a passion for home-brewing into a business that’s focused, at least initially, on making Belgian-style beer, an Old World favorite.

Tkach has invested around $50,000 of his own money in the operation - for now, he wants to keep total control over product and distribution - while awaiting his state brewing license, so he can actually get started. “It will be a true nano, at least for now,’’ says Tkach.

Larger in both scale of operation and capital investment are the microbreweries (up to 1,000 barrels annually). Local start-ups Wormtown Brewery (Worcester), Cape Ann Brewing (Gloucester), Wandering Star, and Jack’s Abby, among others, fall into this category.

Jack Hendler, 28, brings considerable brewing experience to his Framingham operation, having served as head brewer at Boston Beer Works. His plan? Start small, produce a limited line of lagers, and don’t even worry about bottling beer to sell in stores for a year or so. In the meantime, Jack’s Abby will be available in kegs only, marketed mostly to restaurants and taverns in the Metro West and Boston areas.

“We don’t want to get ahead of ourselves,’’ says Hendler, who has invested about $500,000 in the brewery.

Eric Hendler, 26, a former Manhattan commodities trader, and brother Sam, 21, who’s finishing a University of Vermont degree program, make the Framingham brewery a family affair. They’re also growing their own hops at a family farm in Shaftsbury, Vt., another locavore touch.

“It’s good timing for the three of us,’’ says Jack Hendler. “A way for guys with home-brewing experience like us to get into the market for real.’’

Hoping to expand annual production from 1,000 barrels to 2,500 in coming years, he credits Boston Beer Co. (maker of Sam Adams) for not only inspiring local brewers like himself but for imparting valuable expertise as well.

For three years, the Boston brewery has been running its Brewing the American Dream program, aimed at the food and beverage industry in general. The program, which is expanding nationally, provides expertise in marketing, sales, financing and legal issues, social media, and other services. To date, about 1,400 small business owners, some of whom have also received microloans, have passed through the program, which is offered without charge. One notable success story is Somerville-based Pretty Things Beer and Ale Project, makers of Jack D’or Belgian-style ale.

Chris Lohring may never see his beer compete with Sam Adams for market share. But his passion for the brewing game is reminiscent of what drove Boston Beer Co. founder Jim Koch, a quarter century ago, to sell his product with nearly evangelical zeal.

At the Ipswich brewery one recent morning, Lohring roamed among the gleaming silver tanks holding his latest production run: 30 barrels of session ale and 60 barrels of pilsner. That worked out to 432 cases of beer, plus another 100 kegs.

“In the ’90s, we were selling the concept of craft beer, but we’ve come a long way since,’’ Lohring said. “Now, it’s about what you can bring to the market. If you don’t bring something unique, you’ll get lost in the mix.’’

Joseph P. Kahn can be reached at jkahn@globe.com

© Copyright 2011 Globe Newspaper Company.