Sales are up for all Goose Island brands this year, with interest in 312 Beer -- named for the original Chicago telephone area code -- increasing in the United Kingdom as well as the U.S.

"Of all the places where the 312 messaging shows up after the Obama comments," Hall said, there were "as many e-mails in the first couple hours from England as the U.S."

Obama usually avoids making overt product endorsements. After he visited China last year and was photographed in a jacket by the Weatherproof Garment Co. -- and Weatherproof put the picture on a Times Square billboard -- the White House wasn't pleased.

On Tuesday, when Obama hosted Cameron at the White House, he started their news conference with a reference to the Chicago brew.

"We have just concluded some excellent discussions -- including whether the beers from our hometowns that we exchanged are best served warm or cold," Obama said.

"My understanding is, is that the prime minister enjoyed our 312 beer, and we may send him some more. I thought the beer we got was excellent -- but I did drink it cold."

Last month, Obama and Cameron paid off World Cup bets with a televised beer exchange while in Toronto for the G-20 and G-8 summits. Since the U.S.-England game ended in a draw, Obama gave Cameron 312 beer and Cameron sent Obama Hobgoblin from the Wychwood brewery in Witney, in his home constituency.

At the White House, Cameron said: "I did enjoy drinking the 312 beer -- cold -- during the World Cup. I enjoyed it so much that, when I watched Germany beat Argentina, I actually cheered for Germany. That's something that's a big admission for a British person to make. So the beer is obviously very effective."

ABC-TV news anchor Diane Sawyer even asked Cameron about "Goose Island 312" during an interview: "Did you have it cold? How was it?"

Cameron's reply: "I've -- as ordered to by the president -- I put it in the fridge. And I've been drinking it while watching some of the World Cup. And it's very good. It's very good beer. Beer from Chicago, very different from the stuff we have back in the U.K. but good nonetheless."

Said Hall, it "certainly does not hurt when the leader of the free world touts your product."