BUFFALO, N.Y. (AP) — Never in its 50-year history has Starbucks relied on union workers to serve up frothy lattes at its U.S. cafes. But some baristas aim to change that.

Workers at three separate Starbucks stores in and around Buffalo are expected to begin voting by mail this week on whether they want to be represented by Workers United, an affiliate of the Service Employees International Union.

The National Labor Relations Board’s regional office in Buffalo, which approved the vote last month, is scheduled to start mailing ballots Wednesday evening and count the votes on Dec. 9.

Starbucks appealed late Monday, asking for a delay in the election while it waits for the full NLRB in Washington to review its case. But the vote may proceed even as that review is held.

It’s a rare union vote for the coffee giant, which has fought off a handful of other unionization efforts over the last two decades. It comes at a time of increasing worker unrest across the U.S. Amazon warehouse workers in New York are also seeking a union election this fall, while thousands of unionized workers at Deere & Co. and Kellogg Co. are on strike.

Dan Graff, director of the Higgins Labor Program at the University of Notre Dame, said many workers are burned out and tired of playing by the pre-coronavirus rules. They were deemed essential during the pandemic, but find they are still struggling with inflation, child care and disrespect from employers and customers.

“It’s a fraught public space that we live in right now, and more workers have had the opportunity to reflect and think about these issues,” Graff said.

Pro-union workers say they deserve more from Starbucks, which reported record sales of $29 billion in its 2021 fiscal year. They say the company had chronic problems even before the pandemic, including understaffed stores and faulty equipment. They want greater say in how stores are run and how much workers are paid.

“I think if we raise the bar at Starbucks, not only do we make it a better company, a better workplace, but we make the industry better since it is the leader in the industry,” said Jaz Brisack, who has worked for about a year at a Starbucks in downtown Buffalo. Brisack also helped organize a successful unionization effort at Spot Coffee, a small Buffalo chain, in 2019.

Starbucks points to its generous benefits, including paid parental leave, a 401(k) program and free college tuition through Arizona State University. Late last month, it announced pay increases, saying all its U.S. workers will earn at least $15 __ and up to $23 __ per hour by next summer.

The Seattle-based company says its 8,000 company-owned U.S. stores function best when working directly with their employees.

“Every success we have ever achieved has been in direct partnership with one another __ without an outside party between us,” said Rossann Williams, Starbucks’ North America president, in a recent letter to employees that urged a “no” vote in Buffalo.

Graff said Starbucks’ reputation as a generous employer is one reason it’s an ideal target for union organizers.

“When companies frame themselves as good employers who care about workers, often that sets up expectations for workers,” Graff said.

Around 111 employees __ including those at Brisack’s store and two stores in suburban Buffalo __ will be eligible to vote on unionization. The NLRB rejected Starbucks’ request to hold one vote with 20 stores in the Buffalo region and ordered separate votes at the three stores. A majority vote at any one of the stores would create a bargaining unit for that location.

Williams and Starbucks founder Howard Schultz are among the company representatives who have swarmed Buffalo in recent weeks, even closing stores to hold team meetings, Brisack and other workers say. In an NLRB filing this week, Workers United accused Starbucks of threats, intimidation and surveillance of workers.

There’s a lot at stake for Starbucks. Carolyn Plump, an associate professor of legal studies at La Salle University School of Business, said private employers almost uniformly oppose unions because they often result in higher labor costs and less flexibility. Union membership gives workers the legal right to strike and forces employers to negotiate hirings, firings and promotions.

Starbucks has fought union efforts before. Earlier this summer, the NLRB found that Starbucks retaliated unlawfully against two Philadelphia baristas who the company fired in 2019 after they tried to form a city-wide union. The board ordered Starbucks to cease its efforts and reinstate those workers.

The company does have a few unionized locations in other countries, including a store in Victoria, Canada, that was organized in June.

U.S. labor law largely favors employers, with weak penalties for those that interfere in union elections. As a result, only around 6% of U.S. private sector employees are unionized, compared to about one-third of public sector employees like teachers, said Cathy Creighton, the director of Cornell University’s Industrial and Labor Relations Buffalo Co-Lab.

Creighton said unions can actually help a company. Better-paid workers are more stable and less likely to leave, she said.

“A low-wage workforce is not a productive workforce,” she said.

The organizing efforts at Starbucks are already starting to spread. On Tuesday, three additional Buffalo-area stores filed petitions to unionize, evidence that momentum is growing, said Michelle Eisen, a leader of the unionization efforts.

Still, not every Starbucks worker is backing the union drive. Tia Corthion has worked at a Starbucks on the outskirts of Buffalo for two years and was recently promoted to shift supervisor.

Corthion, who has also worked at Walmart and Home Depot, says Starbucks is one of the best employers she has had. She appreciates the benefits and says she feels the company listens when she offers suggestions.

“If I can say something is wrong and the problem is fixed, why do we need to pay somebody to fix the things that we need to do?” Corthion said.

Even if employees at the three stores vote in favor of unionization, there’s no guarantee they will get a contract, Graff said.

If a union vote survives appeals and is certified by the NLRB, the employer is legally obligated to begin the process of collective bargaining. But often, companies drag out that process, since there is no law requiring both sides to produce a contract.

More than half of all workers who vote to form a union are still without a collective bargaining agreement a year later, according to the Economic Policy Institute, a think tank. In 2017, workers at a Dollar General store in Missouri voted to unionize; after exhausting its legal appeals, Dollar General wound up closing the store.

“In today’s United States, if an employer doesn’t want to accept unionization at a workplace, it’s unlikely it will happen,” Graff said.