To think we've been doing cold lattes all wrong all these years.

Ice cubes in a cup. Add cold milk. Add hot espresso. Sweeten.

Bad technique, says La Colombe co-founder Todd Carmichael, ruefully.

Melting ice cubes weaken the drink. There's the inherent bitterness of the espresso, which he says is magnified by the sudden change in temperature. (Carmichael has been in the coffee biz for 31 years. Aside from his wife and kids and his various traveling adventures, coffee is all he thinks about.)

What if you could keep it cold all along? Cold-brewed espresso that retains the caffeine and flavor. Cold milk. Naturally frothed on top. And dispensed from a tap. Less fuss for a barista, too.

Carmichael called on his engineer buddies to develop assorted valves and whatnot. He enlisted Ted Green, a Drexel grad who works in the rum distillery at La Colombe's Fishtown flagship store, to nail a technique to replicate the flavor and character from batch to batch.

Nitrous oxide is added to the equation to handle the mix. Carmichael says the gas gets turned into a liquid and is dissolved in the milk. The result: A great, creamy cold latte. And a bonus: The natural sugar in the milk becomes more pronounced, meaning that you really don't have to sweeten your drink. You can add ice, but it really comes out of the tap at a satisfying temperature.

Draft lattes are now available at the Fishtown location. Other La Colombe cafes in Philadelphia and around the country will have the equipment this year.

La Colombe also has secured equipment to can the lattes, which will keep under refrigeration for three weeks. The cans, he said, will be distributed nationally.