For some caffeine lovers, there’s nothing more refreshing than adding some ice to a cup of coffee or tea to bring the temperature down and the energy levels up. Balance is important — too much ice and not enough coffee can result in a weak drink. According to a new lawsuit, Starbucks baristas have been upsetting that balance by allegedly adding too much ice to cold coffee drinks, and skimping on the liquid.

A Starbucks customer filed a class action [PDF] against Starbucks in Northern Illinois Federal Court last week, claiming that the chain’s cold drinks are almost half ice, and that Starbucks misrepresents the fluid ounces of its iced coffee and tea beverages.

In the complaint, the lead plaintiff points out that Starbucks makes a hefty chunk of change on cold drinks prepared in-store, “accounting for billions of dollars in revenue” each year.

Despite the fact that Starbucks advertises four sizes of drinks — Tall, Grande, Venti, and Trenta, which correspond to 12, 16, 24 and 30 fluid ounces, respectively — the plaintiff claims that customers don’t get the full advertised fluid ounces because the company fills much of those cups up with ice.

“A Starbucks customer who orders a Venti cold drink receives only 14 fluid ounces of that drink — just over half the advertised amount, and just over half the amount for which they are paying,” the 29-page complaint states. “In the iced coffee example, a Starbucks customer who orders and pays for a Venti iced coffee, expecting to receive 24 fluid ounces of iced coffee based on Starbucks’ advertisement and marketing, will instead receive only about 14 fluid ounces of iced coffee.”

What this all boils down to, the complaint says, is that Starbucks is, in essence, “advertising the size of its cold drink cups on its menu, rather than the amount of fluid a customer will receive when they purchase a cold drink — and deceiving its customers in the process.”

Adding insult to injury, the customer claims, is that Starbucks charges more for cold drinks than their hot partners, even though customers opting for the cold version get less of the product than hot-drink customers.

That enables Starbucks to reap higher profits off cold drinks, the complaint claims: “Starbucks’ Cold Drinks are underfilled to make more money and higher profits, to the detriment of consumers who are misled by Starbucks’ intentionally misleading advertising practices.”

To solve this problem, the plaintiff suggests, Starbucks could serve cold drinks in larger cups that allow room for the advertised amount of beverage, while still allowing for ice.

“Starbucks is misleading customers who expect to receive the advertised amount of fluid ounces,” the lawsuit states. “For example, if a gallon of gas is advertised as costing three dollars, and a customer pays three dollars and pumps gas, that customer is expecting to receive a gallon of gas — not approximately half a gallon.”

The plaintiff is seeking to represent a class of anyone who bought a cold drink from Starbucks in the last 10 years. She’s accusing Starbucks of breach of express warranty, breach of implied warrant of merchantability, negligent misrepresentation, unjust enrichment, and fraud.

“We are aware of the plaintiff’s claims, which we fully believe to be without merit. Our customers understand and expect that ice is an essential component of any ‘iced’ beverage,” a Starbucks spokesperson told Courthouse News. “If a customer is not satisfied with their beverage preparation, we will gladly remake it.”

Starbucks is under fire on the hot side of its beverage menu as well: just last month, customers filed another lawsuit accusing the chain of underfilling lattes.

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