Sweet land of ice cream

On a steamy night at Toscanini's in Central Square, Cambridge, a customer in the ice cream shop grabs a root beer from a small cooler and passes it over the counter to the clerk, who pours it into a tall cup filled with vanilla ice cream. When the root beer hits the ice cream, it foams up and results in a thick, sudsy float that requires both a spoon and a straw.

Summer is ice cream cone season, but all the frozen creamy drinks -- floats, milkshakes, frappes, and smoothies -- also have a following. These tall, cooling glasses are typically American: grand in presentation, ample in flavor, and loaded with luscious calories. Though other cultures have their icy drinks, no one tops them full of ice cream the way we do. And in Boston, ice cream drinks come with their own quirky language.

''The real savoring of a milkshake is taking swallow after swallow and drinking it right down," says Steve Herrell, founder of Herrell's Ice Cream, who likes his milkshakes with an extra scoop of ice cream added at the end. ''On a hot day, it can cool you off from the inside so wonderfully."

If you grew up in Greater Boston, you might wonder which milkshake the ice cream entrepreneur is referring to. Many Bostonians still think of a milkshake as milk and syrup, shaken until frothy. But drinking a Boston milkshake doesn't have the same cooling effect as drinking a tall cup of blended milk, syrup, and ice cream. In this city, that's a frappe.

The distinction is unusual, since a frappe is a milkshake for the rest of the state and the country. Boston-area ice cream merchants get around the linguistic quirk in various ways. ''When people come in and order a milkshake, we always ask if they want it made with ice cream," says Vinnie Jankord, owner of the downtown Brigham's on High Street. ''And most people do." But will Brigham's ever stop distinguishing between frappes and milkshakes? Jankord, who's been with the company for 28 years, says, ''No chance."

Brigham's is one of few local places that differentiate between the two beverages. At J.P. Licks, if a customer orders a milkshake (although you won't find it on the menu), it comes with ice cream, says owner Vince Petryk. Since 1981, when he opened his first store in J.P. Center, ''we've never had many requests for Boston-type milkshakes." Petryk estimates that 85 percent of the ice cream drinks ordered at his stores are frappes, with floats and ice cream sodas accounting for 10 percent and 5 percent respectively.

Petryk, who enjoys the combination of root beer and vanilla ice cream enough that he tried for years to make root beer ice cream, thinks that ''the day has passed" for drinks like floats and other ice cream sodas. ''They were products of the soda fountain," and in today's ice cream shops, where moving the line along is a priority, ''the technique is too tricky," Petryk says, ''and it's hard to keep the results consistent."

Demand for floats and ice cream sodas might be dwindling, but it's not the same for smoothies. The frappe's healthy cousin is a more recent phenomenon, and it's especially popular in urban areas with young populations. Herrell started a smoothie program for his stores in 1998 and says that the smoothies ''bring in a new type of customer." His blended fruit drinks are made with just frozen fruit and juice. Many places will blend the fruit with milk, ice, yogurt, or even ice cream, but Herrell prefers to offer dairy-free smoothies and says that ice dilutes the fruit flavor. And he's particular about technique. ''You don't want leftovers or chunks of fruit in the finished product," Herrell says. ''By definition, that's not smooth."

Of all the frozen drinks, the ice cream merchants agree, the frappe is the most popular. ''Frappes rule," says Toscanini's owner Gus Rancatore, whose favorite is made with green tea ice cream. ''They're the ultimate summer drink."