A Chicago woman is suing Starbucks for more than $5 million (R73 million), claiming that the coffee giant under-fills its popular hand-blended iced coffee, tea and other drinks, making customers overpay for beverages.

In a lawsuit seeking a jury trial and class action status, alleging false advertising and consumer fraud, Stacy Pincus accuses the world’s biggest coffee retailer of serving its customers “much less than advertised – often nearly half as many fluid ounces.”

“As a result of this practice, Starbucks’s cold drinks contain significantly less product than advertised, by design and corporate practice and procedure,” the suit filed last week says.

Starbucks baristas typically fill cold-drink plastic cups to the top black line printed on the cups and then add ice.

Pincus says that since April 2006, she and millions of other Starbucks customers have been defrauded because Venti cup customers get only 0.4 litres of beverage – the amount of liquid obtained when filling cups to the top line – even though menus state a 24-ounce/0.7 litre total.

“Starbucks includes these three black lines on its cold drink cups to ensure that its employees fill these cups with less fluid ounces than are advertised on Starbucks’s menu for a given cold drink,” the lawsuit says.

“In fact, Starbucks instructs its employees to provide its customers with fewer fluid ounces than advertised.”