Given America's love of coffee and super-sized portions, it was inevitable that Starbucks should tie the two together in its latest offering: the massive new "Trenta" cup size, holding 31 US fluid ounces – that's 917ml, or more than one and a half imperial pints – of beverage.

The company says it is responding to customer demand for larger sizes, which it has been testing for almost a year. The Trenta – from the Italian word for 30 – will go on sale in 14 US states this week, and by May will be sold throughout the country.

In a nod to health fears, Starbucks says that only conventional iced coffee, iced tea and iced tea lemonade in both caffeinated and decaffeinated varieties will be sold in the new bladder-bursting cup size, and claims that "sweetened" versions will contain only 230 calories. But if America works up a thirst for the Trenta, it's a good bet that a fishtank full of Frappuchino won't be far behind.

While the Trenta may be one big slurp for Starbucks, it's only a small sip for Americans already able to buy soft drinks such as the Double Big Gulp sold by the 7-11 chain: 64 US fluid ounces (nearly two litres) of carbonated sugar and caffeine.

How much caffeine an individual should consume is another matter, with Starbucks's new bucket equating to around four standard sized cups of coffee. A Starbucks iced coffee of that size would probably contain nearly 400mg of caffeine, not enough to put a Trenta drinker into the heavy user category of 500 to 600mg of caffeine a day.

There are no plans for Starbucks to sell the jacuzzi-sized coffee cup to its British customers. Yet.

Update: Canada's National Post has a revealing infographic showing the Trenta in proportion to a human stomach. It seems the average stomach has a capacity of 900ml – and the Trenta weighs in at 917ml. Not for the faint-hearted or weak-kidneyed.