Yes, that’s a grain silo, in Dorchester

Passersby stopped to ask what was being assembled in front of the Dorchester Brewing Company. Suzanne Kreiter/Globe Staff

Throughout the day Wednesday, drivers slowed down and gawked at the stainless steel cylinder workers were erecting at the new Dorchester Brewing Co. facility near the South Bay shopping center.

This type of three-story silo likely hasn’t dotted the Dorchester skyline probably since ye olde agricultural days of the 1700s, if ever.

“We were trying to figure out when was the last time a silo went up in Dorchester. It’s been centuries,” said Matthew Malloy, chief executive of the Dorchester Brewing Co. and treasurer of the Dorchester Historical Society.

The silo is the crown jewel of the beer-making company’s 25,000-square-foot complex at 1250 Mass. Ave.

The facility will be Boston’s first contract brewery, providing small- and medium-sized beer makers access to equipment to help them brew, package, and distribute their product, for a fee. Malloy, a former Zipcar marketing executive, described the model as the Zipcar of beer — instead of investing in equipment, you can use theirs when you need it.

Standing at 28 feet, the silo will surely stand out along that portion of Massachusetts Avenue, which includes a nearby warehouse and an auto body shop. It will be able to hold up to 50,000 pounds of malt used to make beer.

Having its own silo will allow Dorchester Brewing Co. to pass on savings from buying grain in bulk to its partners, who will be brewing a variety of beers from a cloudy double IPA, to Belgians and sours, Malloy said.

Depending on the beer, microbrewers can pay anywhere from 50 cents to $1.25 per pound for a 55-pound malt sack. It can take about 2,000 pounds of grain to make a 30-barrel batch of beer, Malloy said.

Brewing is expected to start at some point in April or May at the facility, which will add up to 30 jobs to the neighborhood. A 2,000-square-foot tasting room featuring a 20-line tap system may open in June, Malloy said. Large scale manufacturing of beer will commence in late June or July.

Nearly a dozen local brewers have signed up with Malloy, who says he’s in talks with others from as far as the United Kingdom, Canada, and Ireland.

“We have a great model and great solution for them,” he said. “We’re really excited about bringing manufacturing back to Dorchester.”

Nick Bath and Josh LaFranc worked on building the silo from the bottom up. Suzanne Kreiter/Globe Staff/Globe staff