In a separate vote in Overland Park, Kan., the union had six votes yes and one vote no, but there were seven challenged ballots, enough to potentially affect the outcome. The official result will be determined at a separate hearing.

The vote was close at one of the Rochester stores, with the union winning 13 to 11, while the other five stores favored the union by significant margins, according to vote counts confirmed by the NLRB. A Starbucks spokesman noted that turnout was relatively low in Thursday’s elections, however, with only about half of eligible voters participating for one of the stores.

The elections come at a time when organized labor is asserting itself as a combination of strong corporate profits, inflation, worker shortages and pandemic-inflicted hardship has given unions additional leverage.

Labor unions are hoping to capture the moment to expand their reach after decades of retrenchment. They have been pressing hard on contract negotiations, winning back long-lost benefits for their members amid a rash of strikes. And they are moving aggressively to organize nonunion shops. There have been 641 petitions filed with the National Labor Relations Board in 2022 as of Friday, the fastest pace of new petitions since 2008, according an analysis of NLRB data.

A union election last week on New York’s Staten Island culminated in the first successful union drive at an Amazon warehouse, and organizers have filed dozens of petitions to unionize Starbucks coffee shops in at least 25 states.

Starbucks spokespeople and executives have said the company respects workers’ right to organize but doesn’t believe a union is necessary.

In response to a request for comment on Thursday’s union votes, Starbucks spokesman Reggie Borges said: “The priority of [CEO Howard Schultz] and our leaders is to focus on culture: the renewal and a reimagination of Starbucks. We are listening and creating that future with all of our partners. This is the core work ahead and we are excited about the possibility and future.”

In an earlier public letter, Rossann Williams, the company’s executive vice president for North America, promised to bargain in good faith. “Our hope is that union representatives also come to the table with mutual good faith, respect and positive intent,” Williams wrote.

The Seattle-based company’s progressive image has long set it apart from others in the food service industry, and it has sought to burnish its wage and benefits packages over the past year as the union effort has gathered steam. In October the company announced that it would raise its minimum wage to $15 per hour by the summer of 2022, while giving a 5 percent raise to those with two or more years of service.

Starbucks has responded to the worker unrest by reshaping its corporate finances, as longtime chief executive Howard Schultz returns to the job on an interim basis. It announced Monday that it would suspend stock buybacks and allow the company to “invest more profit into our people and our stores.”

Union organizers, meanwhile, have accused the company of running a pressure campaign to prevent employees from organizing. The National Labor Relations Board recently brought a case against the company for allegedly retaliating against an employee who sought to organize her coffee shop in Phoenix.

The employee, Laila Dalton, was later fired after recording a conversation with a manager and publicizing it. A Starbucks spokesman said Dalton was terminated after admitting to recording multiple conversations that she wasn’t a part of, and without the consent of those interested parties.