Ryan Balthrop is deep into his song “Two Less Fishes” when he pauses and looks over at Catt Sirten, the organizer of the Brown Bag concert series that Balthrop is kicking off on this beautiful spring day in Daphne’s Centennial Park.

It’s a fun love song that Balthrop wrote for his wife, saying that when they got together, that meant there were two less fish left in the sea. But here in this moment, Balthrop has just realized that the next line might not be appropriate for the small mob of elementary school kids gathered around the pavilion where he’s playing. After a momentary hitch, he ad-libs “… sand in my britches,” and carries on.

Off to the side, Sirten laughs appreciatively. “That’s the part where he usually says ‘son-of-a-bitches,’” he explains.

So it goes at Brown Bag, a lunchtime concert series that is now, incredibly, in its 38th year. The longevity is thanks mainly to the persistence of Sirten, who fired it up in fall 1985, when he was one of the DJs at Mobile’s eclectic WZEW-FM 92.1, a station that still airs Catt’s Sunday Jazz Brunch.

For years – no, make that decades – the series’ home was Bienville Square. All it took was a sponsor or two, a little city support in terms of setting up chairs and tables, and downtown workers had a fantastic lunchtime entertainment option in spring and fall. The lineups were always eclectic, adding to the broad appeal.

Longtime fans may still find it hard to say “Brown Bag” without adding “in Bienville,” but the series grew to sprawl across the bay. At its peak, a Brown Bag artist would play Wednesday in downtown Mobile, Thursday on the Daphne waterfront and Friday in Fairhope.

But sponsorships and municipal support come and go, and every once in a while you get a major pandemic that just generally screws things up. For its 38th season, Brown Bag takes place only in Daphne’s Centennial Park, where it moved because of major work being done in the bayside May Day Park.

At this point, Sirten seems to take the changes in stride. He had to be stubborn to keep it going this long. “I choose to use the word ‘tenacious,’” he said.

There’s no guarantee that future Brown Bag performers will find the park full of schoolkids on a field trip, as it was for Balthrop. But it made for an interesting dynamic: Brown Bag regulars showed up with chairs and food and tended to gravitate toward the shade of the park’s impressive oaks. It was the kids who crowded forward to the edge of the pavilion, some of them dancing.

But there’s a distinct possibility that Balthrop won’t be the only one to benefit from such energy.

“We have a lot of field trips that take place in Daphne city parks,” said Kara Wilbourn, a marketing coordinator for the city of Daphne, who happened to be on the scene. “This is a Daphne favorite event,” she said.

The upcoming lineup is a product of Sirten’s not-so-secret formula. Aside from diversity of genre, he insists that every season feature both proven favorites and fresh blood.

The schedule:

April 20 – Eden & Raul (acoustic rock)

April 27 – Vocalist Karmilla Ali with guitarist Jim Armstrong (jazz)

May 4 – Excelsior Band (traditional jazz)

May 11 – Kevin Danzig (pop)

May 18 – Jamell Richardson (blues)

May 25 – Leo Miller (pop/rock)

June 1 – Quintin Berry (funk)

Concerts take place from 11:30 a.m. to 1:30 p.m. Thursdays through May. Centennial Park is at 1706 Main St., across from Daphne City Hall.