First it was Subway shortchanging its footlong sandwiches.

Now caffeine addicts are up in arms over Starbucks allegedly under filling its lattes.

A class-action lawsuit filed Wednesday in the U.S. district court of Northern California, claims that the coffee chain knowingly and systematically serves customers lattes that are 25 percent smaller than the menu claims.

The plaintiffs allege that Starbucks not only uses too little liquid in its standard latte recipe but that its cups are not adequately large enough to contain the amount of beverage stated on their size menu. So if you ordered a grande (16 ounce), it’s really more like drinking a tall (12 ounce).

Court documents state, "Starbucks Lattes are made from a standardized recipe, which Starbucks instituted in 2009 to save on the cost of milk — one of its most expensive ingredients."

The "fill to" lines etched on the pitchers used by baristas to heat milk result in drinks don't measure up to the tall (12 ounce), grande (16 ounce), and venti (20 ounce) sizes listed on the menu. "By underfilling its lattes, thereby shortchanging its customers, Starbucks has saved countless millions of dollars in the cost of goods sold and was unjustly enriched by taking payment for more product than it delivers."

The lawsuit claims Starbucks knowingly engaged in false advertising and has committed fraud. The lawyers are demanding a trial by jury and seeking compensatory and punitive damages as well as restitution for all those affected.

Four attorneys are named as plantiff representatives and if the lawsuit’s class action status is approved, it would be “open to all U.S. Class Members who purchased a Starbucks Latte"—potentially of millions of customers.

A Starbucks company spokesperson told Eater that "We are aware of the plaintiffs' claims, which we fully believe to be without merit. We are proud to serve our customers high-quality, handcrafted and customized beverages, and we inform customers of the likelihood of variations."