Starbucks (SBUX) is rolling out an even bigger drink size. The 31-ounce Trenta will be available in all of its coffee stores by May 3, Reuters reports.

At first the Trenta will be available only for iced coffee and iced tea. It's a monstrously large serving, about 7 ounces larger than the Venti already available for iced drinks. It'll cost about 50 cents more.

"Trenta" is the number 30 in Italian, so it's full speed ahead for Starbucks to Quaranta (40) and Cinquanta (50). Just an FYI: The average adult human bladder can hold about 17 ounces.   

Now we know why Starbucks is trying to play down its "tall" size, which is a mere 12 ounces. It needs to make room on the menu for the newest addition. (There's also the 8-ounce "short," which isn't on the menu at all.)

Post continues after video:
The Trenta helps Starbucks compete with McDonald's (MCD), which sells 32-ounce cups of sweet tea. And it's larger than the coffees you can get at Dunkin' Donuts and 7-11 convenience stores, The Daily News reports.

Starting tomorrow, people can get the Trenta in Arizona, Texas and Florida. California will have it by Feb. 1.

Do we really need drink sizes to get this big? Starbucks has been testing the Trenta for nearly a year in select markets, and apparently the answer is yes.