In the heart of San Francisco, technology is inventing the future. Out on the western edge of town, an institution with deep roots in the city is faced with reinventing itself to have a future.

Not long ago, the United Irish Cultural Center on 46th Avenue near Ocean Beach had an important role in the life of one of the region’s major ethnic communities. But now, because of changing demographics and the emergence of a new San Francisco, the center will suspend operations of its bar and restaurant — once a mainstay of its operations — on Oct. 31, according to Michael Barnacle, president.

Closing a money-losing bar and restaurant may seem like small potatoes in the social life of the city, but the problems of the Irish center are symptoms of the larger changes in the city. The Irish center, which has roots in Irish clubs that date back to the 1850s, had 5,000 dues-paying members 30 or so years ago. Now it has 1,200 members, not enough to support a food-and-beverage operation that was losing up to $40,000 a month.

The center itself is not closing, but Barnacle says it will have to have a new focus to survive. “We will have to reinvent the site,” he said.

Barnacle hopes to return the Irish center to what he calls its core mission with programs that reflect Irish culture and heritage.

The Irish center’s problem has roots in the demographic shifts in San Francisco that started around the time of the Summer of Love in 1968. The old, white middle-class and working-class families moved out — mostly to the suburbs. The Peninsula, Marin and the East Bay are full of expatriate San Franciscans.

New people moved to San Francisco with different loyalties. And now there’s a tech boom.

The Irish center was not unique in an older San Francisco. There were dozens of ethnic organizations: Slovenian, Finnish, Swiss, German, Italian, Swedish, Filipino and, of course, Chinese. Many have faded away as their founding families died off, became assimilated into the larger culture or moved away. Part of the problem is the decline of social clubs, and part an aging membership.

The Irish center has been hard hit. The annual dinner and dance of the Connaught Athletic and Social Club used to draw 400 people to the Irish center. “Last Saturday night we had 150, and in age they were on the high end,” Barnacle said. “We need to get more younger people in here.”

Patrick Goggins, chairman of the board of the Irish Literary Society, went to see “Don’t Leave Home,” an Irish movie at the Roxie Theatre in the Mission District. The theater was full. “But they were all preppy types” — young people, Goggins said.

The Irish experience is typical of the shifts in the city. The Roxie is on 16th Street and opened in the days when the Mission was the heart of Irish San Francisco. But years ago, those families moved to the Richmond and Sunset districts, and when the United Irish Cultural Center opened in 1975, that part of the city was as green as Ireland. Now the western half of the city is heavily Asian.

It’s a new San Francisco, and “as the old institutions fade, younger people are turning to other things,” Goggins said.

Problems at the Irish center are important because the Irish are part of the region’s DNA. They have had a presence in the Bay Area for what seems like forever. The first Irishmen came before the Gold Rush — John Reed, born in Dublin, came to the Mexican town of Yerba Buena in 1826, and later built the sawmill that gave the town of Mill Valley its name. Jasper O’Farrell laid out the streets of the new city of San Francisco, and the Scots-Irish politician John Geary was the first American mayor. At one time, it was said, a third of the city was of Irish descent. They were politicians, cops, nurses, millionaires, working people, a bedrock of what is now the Bay Area.

Sean Canniffe, publisher of the the Irish Herald, a monthly paper published on the Peninsula, said there are 3½ million people of Irish descent in California, almost 10 percent of the population. The Irish community is thriving, he said.

But the community has changed.

Even conservative, Catholic Ireland has changed. The Irish voters approved same-sex marriage two years ago, voted out a ban on abortion this year, and chose a gay prime minister last year. It’s not your grandmother’s Ireland.

That’s the challenge at San Francisco’s Irish center. It has to refocus. He’s convening a membership meeting Thursday to see what can be done.

Cutting out the food and drink is a tough call.

“It’s bittersweet,” Barnacle said. “I don’t just want the place to survive but to thrive. I’m optimistic.”

Carl Nolte is a San Francisco Chronicle columnist. His column appears every Sunday. Email: cnolte@sfchronicle.com Twitter: @carlnoltesf