Unofficially, the music began late Friday night in Limestone with a few swirls of guitar noise that led to a full-scale jam. It was just a sound check, but it lasted nearly two hours and drew hundreds of people to the outskirts of the gated concert field, creating a pulse of excitement about what the weekend held in store musically.

Officially, the music began around 5:30 p.m. Saturday when Phish launched full tilt into its first set of the weekend festival. The band received a charged response from gleeful fans who stomped their feet and belted out the chorus of the first song “AC-DC Bag.” The punchy, uptempo, guitar-driven song, with a touch of bluesy piano, set the vibe for the two-hour performance.

After 10 minutes of spiraling guitar work from Trey Anastasio, the band sent the song into double time before a crescendo close. From there, Phish eased into “Yamar,” a slightly slower number, led by the band’s bassist, Mike Gordon.

The band found the song’s groove after some minutes of Anastasio’s understated soloing, highlighted by the steady hum of Page McConnell’s organ before sliding off into a netherworld of noodling, albeit intense noodling.

Phish captivated the audience with its buoyancy and intensity from these opening numbers and throughout its sets, which included bouncy fan favorites such as “Meat Stick,” a rollicking song that featured a breakdown in which Anastasio and Gordon laid down their instruments to lead the audience in a hokeypokey-style dance before closing the song with an intense and wah-ing guitar solo. The band also delighted with an extended version of “Birds of a Feather,” another jumpy, high-energy song that spirals into hectic solos by Anastasio, underscored by punches of McConnell’s organ.

Both band and audience kept up an enthusiastic musical dialogue as the sun slipped low and the cooling air became punctuated by the smell of mud, cigarettes and the sweet, burnt-earth aroma of marijuana being smoked.

The set ended just before sunset with “Cavern,” a stompy, feel-good rocker with get-your-groove-on power. The song left a buzz in the air and sent fans off humming into the night, ready for more.