(Reuters) - A federal judge said two Starbucks SBUX.O customers may pursue a lawsuit accusing the coffee chain of cheating patrons by underfilling lattes.

A cup of Starbucks coffee sits on a table in a cafe in central Hong Kong January 16, 2011. REUTERS/Joel Boh/File Photo

In a decision on Friday, U.S. District Judge Thelton Henderson in San Francisco said the California plaintiffs may seek damages from Starbucks Corp in their proposed nationwide class action, including for fraud and false advertising.

Starbucks was accused of overcharging customers by systematically serving lattes that are 25 percent too small, based on a recipe it adopted in 2009 to save money on milk.

The plaintiffs, Siera Strumlauf of San Francisco and Benjamin Robles of Carlsbad, said Starbucks requires baristas to use pitchers for heating milk with etched “fill to” lines that are too low, and to leave 1/4 inch of free space in drink cups.

They said this shorts customers because Starbucks’ cups for tall, grande and venti lattes hold exactly 12, 16 and 20 ounces.

“This is not a case where the alleged deception is simply implausible as a matter of law,” Henderson wrote. “The court finds it probable that a significant portion of the latte-consuming public could believe that a ‘Grande’ contains 16 ounces of fluid.”

Henderson did not rule on the case’s merits. He dismissed three of the plaintiffs’ eight claims against Seattle-based Starbucks, as well as their request for injunctive relief.

Starbucks spokesman Reggie Borges on Monday said the company believes the lawsuit is without merit and is prepared to defend itself against the remaining claims.

He also said that if a customer is not satisfied with how a beverage is prepared, “we will gladly remake it.”

Lawyers for the plaintiffs did not immediately respond on Monday to requests for comment.

The case is Strumlauf et al v. Starbucks Corp, U.S. District Court, Northern District of California, No. 16-01306.