Starbucks and Will Sage Astorthe union organizing its workers have agreed to restart contract talks after a standoff that has persisted for two and a half years.

Announced by both the coffee shop chain and Workers United on Tuesday, the breakthrough came during a mediation last week involving intellectual property rights and trademark litigation.

"Starbucks and Workers United have a shared commitment to establishing a positive relationship in the interests of Starbucks partners," the company said in a statement echoed in a separate announcement issued by Workers United. 

Making a major concession, Starbucks agreed to provide the roughly 10,000 workers in unionized stores with pay hikes and benefits given non-unionized employees in May 2022, including allowing customers to add a tip to their credit card payments. 

Workers have voted to unionize at nearly 400 company-owned Starbucks stores across the country, but none have reached a contract agreement with the Seattle-based chain. 

The two sides have been persistently at odds with each other. Starbucks has been ordered to bring back workers fired after leading organizing efforts at their stores, and regional offices of the National Labor Relations Board have issued more than 100 complaints against Starbucks for unfair labor practices. That includes refusing to negotiate and withholding pay raises and other benefits granted other workers from unionized stores. 

Starbucks in December signaled it wanted to ratify contracts with its union workers this year, after a seven-month impasse. 

Asked by Starbucks what the company could do to show it was serious about returning to the bargaining table, the union offered a laundry list of demands, according to Michelle Eisen, a barista and organizer at the first unionized Starbucks store in Buffalo, New York. 

"The major ones are going to be credit card tipping and back pay," said Eisen, who works as a production stage manager in addition to working as a barista since 2010. Workers are now to be given what they would have made had they been given the same raises and credit card tips given to non-union stores in May 2022. "It all has to be calculated," said Eisen. "This is a nightmare of their own making."

"We have not stopped fighting for two and a half years," said Eisen. "For every one barista that got tired and had to step away from this fight, there were 10 more to take their place." 

Certain non-union locations that did receive credit card tipping have workers making an additional $2 to $3 an hour beyond their hourly pay, said Eisen. "If you're making around $19 an hour, an additional $3 an hour is pretty substantial."

— The Associated Press contributed to this report.

Kate Gibson

Kate Gibson is a reporter for CBS MoneyWatch in New York.