Starbucks Corp, responding to customer demand for larger cold beverages, is selling 31-ounce (916.8 ml) iced teas and iced coffees in Phoenix and Tampa as part of a limited market test, the coffee chain said on Tuesday.

The move from the world's biggest coffee chain comes as some McDonald's Corp restaurants around the United States continue to offer 32-ounce (946.4 ml) sweet tea for $1 in a bid to draw customers to stores.

Such large drink sizes are particularly popular in warm climates in the southern United States, where convenience stores do brisk business selling drinks in even larger containers.

Starbucks has dubbed the new 31-ounce size Trenta and sells iced coffee in that larger cup for $3.30. The Trenta iced tea sells for $2.60.

Starbucks' current largest size is a 24-ounce Venti cup used for serving iced coffee and other cold drinks. The chain also uses 20-ounce Venti cups for brewed hot coffee and other beverages.

Unsweetened Trenta drinks have fewer than 5 calories, while sweetened versions of those beverages have less than 200 calories, Starbucks said.

McDonald's last summer rolled out its McCafe espresso coffee drinks, which have boosted sales and taken direct aim at Starbucks' popular lattes, cappuccinos and mochas. The fast-food chain now is introducing frappes that compete with Starbucks' Frappuccino blended beverages.

(1 US fluid ounce = 29.57 milliliters)

(Reporting by Lisa Baertlein; Editing by Phil Berlowitz)

Coffee