Guitarist Neal Casal tells Billboard how a jam in Ventura, Calif., yielded insta-band Franklins of the World and the soundtrack to the Dead's five-night run.

The Grateful Dead's Fare Thee Well run, which kicked off Saturday, June 27 at Levi's Stadium in Santa Clara, Calif., brought out the jams in a big way -- not just onstage, but during the hour-long set break.

That's when fans got to hear original music composed by Neal Casal (of Chris Robinson Brotherhood/Hard Working Americans fame) and a group of musicians he recruited and (jokingly) named Franklins of the World. He got the gig after Bill Kreutzmann's son, Justin, a noted filmmaker who curated the visual component during set break, asked him to come up with a minimum of five hours of original music to soundtrack the nightly Fare Thee Well time-out.

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As in all things Dead, the music will change from show to show, Casal tells Billboard. On night one, the selection was of the drone-y variety, but there's plenty more material taking the jams in other directions.

The goal was to "capture the essence of" the Dead but not "mimic" the band, says Casal. "So we would do something in the the realm of 'The Wheel,' but isn’t 'The Wheel,' or we'd go for the general vibe of 'Playing in the Band.' We had some guidelines to work from, but we just went from there."

All of the music came together over a two-day live recording session at Castaway 7 Studios in Ventura, Calif. Players included Adam MacDougall, Casal's bandmate in the Chris Robinson Brotherhood, Dan Horne, who plays in Beachwood Sparks and with Cass McCombs (another Casal side gig) and drummer Mark Levy, a member of the band Congress.

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"We didn't have too much time, so we would talk over a certain feel that we wanted, play for 10 to 15 minutes and rehearse the part once or twice," Casal explains, adding that sometimes, "we'd start out in the style of a Dead song but eventually stray from the script and end up in these spaces where none of us had been before. It became quite an adventure, which didn't end up sounding like the Grateful Dead, but was in the spirit of the band."

Indeed, titles for the "songs" nodded to several Dead favorites. "'Scarlet Magnolias," "Friend of the Dead," "Dealbreaker" and "Fakedown Street" were among the names used to identify distinct pieces. "Some were over 20 minutes long, which is not easy to play and keep it engaging and interesting."

Adding to the challenge, "Justin wanted music that didn’t repeat so it's not the same program for every show," says Casal. "I thought it was kind of insane, because it is."

Fans wondering if they can purchase or download the music should sit tight -- although the option isn't available now, positive reaction on social media may open the door to a release down the road.

As for Casal's own take on Fare Thee Well, which he watched from the back of the stadium. "It was awesome," he says. "Trey [Anastasio] did such a good job, especially of how he handled his role --- approaching it like a band member. He doesn’t command your attention, but if you pay attention, it sounds great. It didn't seem burdened at all. It was a light feeling all night long."