Starbucks secret: Dark French Roast ‘is not 100% coffee,’ says complaint

According to The Post, a popular Starbucks coffee variant may contain potassium that is not mentioned, endangering ignorant customers who think they are drinking pure coffee.

According to the complaint, independent laboratory testing revealed that Starbucks' dark roast included 13% more potassium than its house blend as well as the dark roasts from Dunkin' Donuts and Lavazza.

The case claims that "these considerable differences... can only be explained by the deliberate addition of potassium to the coffee during Starbucks' production process."

The filing claims that adding potassium results in a "less-bitter" cup with less acidity, but does not support Starbucks' claim that its coffee is "100% Arabica."

If the complaint is true, the extra potassium was probably added "for the sake of taste" or to lessen the acidity of the coffee, according to Shibamoto.

Puroast, a firm based in North Carolina that offers high-antioxidant coffee and claims to be 70% less acidic than other brands, filed the complaint against Starbucks.