On Monday, May 15, national coffee chain Starbucks introduced ice cubes made of coffee at 100 of its stores in St. Louis and Baltimore for an eight-week trial run.

While freezing leftover coffee into ice cubes isn’t necessarily a new concept, but this is the first time a major chain will be freezing fresh coffee, with the ice coming ready-made and packaged for baristas to break up into beverages.

Customers can opt to have the special coffee cubes added to their drinks for 80 cents extra. For cold brews and frozen coffee drinks, this will help to avoid the beverage becoming watered down by regular ice cubes.

A Starbucks spokesperson told CNBC, “As a company, we often test new products, programs, and ideas to gather feedback from our customers and partners (employees).” The idea could become popular with customers looking for an extra boost to their beverages without having to pay for additional shots of expresso.