SHANKSVILLE, Pa. - Joe Biden let loose with some volunteer firefighters after attending a service honoring the fallen heroes of Flight 93 on the eleventh anniversary of the 9-11 terrorist attacks.

Making an unannounced stop at the Shanksville Volunteer Fire Department during one of their grill out sessions, the vice president was approached by Deputy Chief Brad Shober, 44, who showed him a challenge coin Biden had given him last year.

"Next time I see you, if you have that coin, drinks are on me. If you don't have it, drinks are on you," Shober recalled Biden telling him at the time.

Biden, caught Tuesday without his coin, asked for a rain check and offered to host Shober and his fellow firefighters for a drink in Washington.

"He's going to call you," Biden said, pointing to an aide. "No bulls***."

After noticing reporters, Biden scrubbed the expletive. "This is no malarkey. You come to the White House. I'll buy you a beer."

The vice president raved about the ability of volunteer fire fighters to juggle their day jobs, personal lives, and firefighting duties.

Turning to Interior Secretary Ken Salazar and Transportation Secretary Ray LaHood, who were accompanying him for the trip, Biden recalled courting volunteer firefighters during his first campaign in 1972, "I went to the fire convention, I said, 'look, there are political parties in Delaware: Democrats, Republicans, and volunteer firefighters. I only want one, volunteer fighters.' "

"You know, I am the only non-volunteer fireman that's been made -- in all the history of the Delaware volunteer fire association -- president emeritus, only one," Biden said proudly.

Salazar, chuckling, demurred "President emeritus?"

"President emeritus!" Biden said. "By the way, as volunteer fire fighters will tell you, that's not a small thing. That's a pretty big deal where I come from."

"Must be his good looks, eh?" someone joked.

On his way back into the motorcade, Biden reaffirmed that Shober would be honoring the beer invite. "We made the deal, right? You're coming down."

Biden was asked if the president might join. He responded with a smile, "I can't promise you Obama. He brews his own stuff, I don't."