The plate glass window separating the hoofers from the Congress Street sidewalk kept fogging up Friday night. Folks walking by slowed down, craning their necks to see through the thin spots. A few rubbed their palms in disappointed circles, realizing the condensation was on the inside. Hot string jazz leaked out when the door was propped open to cool the room and ease the steam.

Inside, Tom Whitehead and the Rites of Swing — two guitars, bass and drums — plucked and strummed for the dancers at the Portland Swing Project’s Friday Night Stomp. A double-dozen couples glided, dipped and bobbed across the hardwood floor. Some wore shorts and T-shirts while others sported neck ties and flowing skirts.

Steve and Deb Carmel, both in their late 60s, dance at the Portland Swing Project’s Friday night Stomp on Congress Street. The pair have homes in Massachusetts and Georgetown and say they always know where they can find a dance in New England. Troy R. Bennett | BDN

At the end of each song, dancers turned and high-fived their partners before finding a fresh one. Hip, 20-somethings paired-up with folks past retirement age before cutting another rug. Partners took turns leading and being led. I swear, nobody sat out two in a row.

“There’s not a lot of people down there staring at their phones,” said Jennifer Kain, an instructor at the project. “The people, they connect with each other for two-and-a-half to three minutes in a way that you don’t necessarily get to connect with people in our modern day life.”

You might have thought swing dancing, born in the first decades of the 20th century and revived briefly in the 1990s with bands like the Cherry Poppin’ Daddies, the Squirrel Nut Zippers and the Brian Setzer Orchestra, was a dead art. Judging by the warm bodies I saw swinging in the dim light on Friday, you’d be wrong.

“It never really died,” said Kain.

Instructors Gillian Davis (right) and Jennifer Kain teach a beginners class before the Portland Swing Project’s Friday Night Stomp at Maine Ballroom on Congress Street. Troy R. Bennett | BDN

The Portland Swing Project was founded about four years ago with the aim of teaching and promoting jazz dancing styles developed since the 1920s, including the Charleston, Balboa, Shag and, most famously, the Lindy Hop. In addition to classes, the project hosts weekly dances  (with recorded and live music) at two venues on Congress Street. A short beginners class starts every Friday and Wednesday night dance.

“The reason that I love it so much is it combines some of the best elements in life,” said Kain’s teaching partner Gillian Davis. “You’ve got live music, you’ve got strangers touching each other — and it’s totally OK — you’re getting some exercise and you’re laughing and smiling a lot.”

Swing project dances run Sept. through June, breaking for the summer. Spring classes have ended, but watch their website for information on the next round.

A pair of dancers tear up the hardwood during the Portland Swing Project’s Friday Night Stomp at Maine Ballroom on Congress Street. Tom Whitehead and the Rights of Swing provided the live music. Troy R. Bennett | BDN

A pair of dancers tear up the hardwood during the Portland Swing Project’s Friday Night Stomp at Maine Ballroom on Congress Street. Tom Whitehead and the Rights of Swing provided the live music. Troy R. Bennett | BDN