It’s come time to hoist an Irish coffee and toast the Brennans.

The third generation of this East Bay restaurant family will close their legendary hangout on Sept. 15, after nearly 60 years in business.

“We have a 25 percent rent increase effective Oct. 1 that we can’t go forward with,” Brennan’s co-owner Margaret Wade said Thursday. For the past 20 years, she and her brother, Barney Wade, have run the University Avenue restaurant that their grandfather Jack Brennan opened in 1959.

It’s been a rare successful run for one family, she said. “We’ve already beat the odds. It’s unusual for a family business to make it to the third generation.”

But now, Wade said, “We’re just another statistic.” That, unfortunately, she said, is the fate of restaurant owners who don’t own their property.

Brennan’s is one of the East Bay’s rare independent restaurants with a unionized staff. The shutdown will affect about 20 employees. The loss of those jobs comes just a couple of months after the closing of another union restaurant in Berkeley, Hs Lordships.

“How sad I am for their sakes that we’re closing,” Wade said, praising the workers for displaying great attitudes.

For the last six decades, Brennan’s has been known not just as a sports bar and the East Bay’s most famous maker of Irish coffees, but as a classic meat-and-potatoes restaurant.

“We have Thanksgiving dinner and St. Patrick’s Day dinner every day of the year,” Wade said, referring to the turkey-and-trimmings and corned-beef platters that Brennan’s serves daily.

The Irish coffee is served all day every day, too. Made with freshly brewed medium-roast coffee and Powers Gold Label Irish whiskey, the drink is finished with a whipping cream that has a higher fat content than regular cream and therefore holds its frothy peak longer.

Founder John P. Brennan, known as Jack, was born in Berkeley in 1890 to a longtime local family. According to the restaurant website, he spent most of his career as a contractor, building such landmarks at St. Mary’s College in Moraga, before getting bored in retirement.

He opened Brennan’s on his 69th birthday: Jan. 16, 1959. When he died in 1976, his wife took over the operation. The Wade siblings’ mother, Elizabeth, took the helm in 1987.

The restaurant has always been in the Fourth Street/University Avenue area, but in two buildings, one next to the other. In 2008, the restaurant moved into its current home, a historic Southern Pacific Railway building that was constructed in 1913 and converted to restaurant use in 1974.

“We look forward to having our historic business occupy this remarkable building for decades to come,” says the family’s website history page.

Details: The restaurant will be open every day, except Labor Day, until Sept. 15 at 700 University Ave., Berkeley; www.brennansberkeley.com.