Developer Bart Blatstein has been a powerful force in refashioning the old working-class, beer-making neighborhood of Northern Liberties into a hipster enclave studded with galleries and cafes. Now, he is about to push that bohemian district in a tonier direction with the construction of an immense, 21st-century retail-and-residential hive on the former Schmidt's brewery site.

Blatstein's company, Tower Investments, will hold a formal groundbreaking today for the first phase of that project, a $30 million retail complex anchored by a Pathmark supermarket. The innovative design by New York's Beyer Blinder Belle Architects & Planners will not only provide the neighborhood with much-needed services, but it promises to restore an urban street wall along Girard Avenue and Second Street.

Depending on how quickly the city's damaged real estate market heals, Blatstein said, he intends to follow up over the next several years with an ambitious agenda of additional projects, including two high-rise apartment towers, townhouses, a hotel, a garage, and a one-acre green park.

When fully built, the dense development will cover the entire 8.5-acre block where C. Schmidt & Sons once fermented and bottled Philadelphia's most ubiquitous taproom lager. A new master plan, prepared by Beyer Blinder Belle and vetted by city planners, calls for a total of 600 residential units, 978 parking spaces, and 110,000 square feet of retail.

Today's groundbreaking also marks the end of a decade-long stalemate between Blatstein and local residents over how to develop the site. When the developer first acquired 14 acres of Schmidt's property at auction for $1.8 million in 2000, his intention was to build a suburban-style strip mall.

The neighborhood, a mix of old-timers, artists and twentysomethings, rose up in rebellion.

As Blatstein now acknowledges, the decade of sparring with the Northern Liberties' community has taught him to appreciate the area's rich urban form. That's especially important because Blatstein is the area's dominant landowner, holding 30 acres scattered over 100 parcels.

With each successive development, his projects have become more sensitive to their surroundings, an eclectic combination of traditional rowhouses and hardy factory buildings that has also become an unlikely laboratory for Philadelphia's most experimental architecture.

Schmidts North, as some are calling the new development, will be arranged so that all five sides of the irregularly shaped block are lined with buildings and active ground floor uses. The edges will start low, in deference to neighboring rowhouses, and build up to a height of 26 stories on the site's southern edge, next to Blatstein's Piazza at Schmidts development. A one-acre landscaped park will eventually tie Blatstein's Liberty Walk, and his egg-shaped office tower at Germantown Avenue, into the future development.

Blatstein and his lead architect, Richard Metsky, have even managed to come up with a design for the supermarket that does not mar the crucial Girard Street corner with blank walls, the downfall of most new supermarkets in Philadelphia.

Supermarkets are reluctant to break up their facades with windows because they are intent on maximizing space for shelving and storage. But the lack of transparency can be deadening for a commercial street.

So Metsky and his team placed the grocery on the second floor of the complex. That freed up the ground floor for other retailers, like banks and hardware stores, which like large shop windows to help attract passersby. The entire retail frontage along Girard Avenue and Second Street will be lined with glass.

Metsky, who has done master plans for clients as various as Princeton University and the Kansas City Live entertainment district, could have settled for prosaic stucco on the upper floor. But the architects jazzed up the supermarket facade with opaque colored glass, arranged in a staccato pattern of grays and yellows. It culminates at Second Street with a clock tower, featuring both a digital clock and a Gothic-style 'S' lifted from the Schmidt's logo.

Because the architects were determined to ring the edges of the site with active uses, all the parking will be on the interior of the block. Supermarket shoppers arriving by car will enter the main garage from Second Street. Pedestrians will take elevators to the store.

Blatstein said the sophisticated arrangement required more effort to piece together, and will cost more to build than a strip mall - about $300 a square foot. But he believes the design will pay off in helping to attract better tenants.

"I've built a lot of strip shopping centers," Blatstein acknowledged, "and I wanted to avoid the temptation to do that here. . . . I kept playing with the site."

Noting that the Girard Avenue stop on the Market-Frankford El is just a block away, he added, "This is a real transportation-oriented development. You never have to use your car."

Nevertheless, the project includes plenty of parking. The retail garage has room for 311 cars on three levels, while a later residential structure will provide 258 spaces.

Although it took Blatstein almost a decade to work out a design the neighborhood would embrace, the components of the current plan are almost identical to the ones he proposed in 2001, and may even include more density than he first envisioned.

For many years, Blatstein resisted hiring a professional planner to lay out the complex project, preferring to do the work in-house. During the final days of the Street administration, he tried to rush an inferior version through the Zoning Board of Adjustment. When that strategy failed, he hired Beyer Blinder Belle and entered serious negotiations with the Northern Liberties Neighborhood Association.

"Beyer Blinder Belle was terrific," said Larry Freedman, who heads the group's zoning committee. "We went from a sea of parking to this, where we don't see parking at all." He likes the design so much, he even plans to attend today's groundbreaking.

Even before hiring the planners, Blatstein had won the neighborhood's trust with his handling of the Piazza. Designed by Erdy McHenry Architects, it includes a generous public open space that has effectively become Northern Liberties' town square.

As Blatstein's thinking has evolved, so has the neighborhood's. It is an increasingly desirable place to live, and not just for artists or singles in their early 20s.

With Schmidts North, neighborhood association president Matt Ruben said, it is inevitable that Northern Liberties will become more upscale. "We realize that being a hipster district was part of the process of gentrification, and we have to be careful not to be nostalgic for a period that is fleeting," he said.

Blatstein's position as a major landholder allows him to shape the transition on his own terms and schedule. The project, which has received several federal tax breaks, is one of the few projects moving ahead.

"I can't think of another neighborhood that has had a single hand transforming it in this way," said Alan Greenberger, the city planning director. "We think the plan is really quite good."