Furthur earlier this tour- photo by Shawn Smith

On one of the hottest nights of the year, Furthur cooled off an appreciative crowd at the outdoor Comcast Center amphitheater in Mansfield, MA with a night of mostly mellow music that dipped heavily into the Grateful Dead catalog of the 1970s and 80s, as well as songs from the solo careers of Jerry Garcia and Robert Hunter’s solo career and Ratdog.

The evening kicked off with a spirited rendition of the New Orleans classic “Aiko Aiko,” whose Cajun feel suited the bayou-like weather conditions (temperatures were well above 90 degrees when the show started shortly after 7 PM). Furthur then set the tone for much of the evening by slipping into the groove of the “Terrapin Station” chestnut “Passenger,” with rhythm guitarist Bob Weir providing enthusiastic vocals.

In several New England-area Furthur performances in the past year or so, the band has drawn heavily on the early, psychedelic portion of the Dead canon. However, this night only featured two sojourns into the pre-1970 Dead lexicon, one being the third song of the evening, the traditionally influenced “Aoxomoxo” number “Doin’ That Rag,” whose start-and-stop, mixed tempo progression was a contrast to the more steadily upbeat song preceding it.

Weir reclaimed the mic from lead guitarist John Kadlecik to shift the pace down a notch with the slow, R&B-flavored “Loose Lucy,” which led into Kadlecik leading a take on the 1980 classic “Althea,” with soulful vocals and playing that demonstrated why Weir and Lesh chose him to step into the massive footprints left behind by Jerry Garcia.

The first set then concluded with two songs originally released on the 1970s Garcia solo album Reflections (although both also did time as Dead live regulars): “Mission in the Rain” and “Might as Well,” with the RatDog original “Two Djinn” sandwiched in the middle. This marked the first time Furthur ever played “Mission in the Rain” live.

In addition, Furthur featured a fair number of RatDog songs earlier in their concert career but seem to have veered away in the past year or so. Along with the solo Jerry tunes, “Two Djinn” served the audience notice they would be served something slightly different than local fans had been used to receiving.

The second set opened with “Foolish Heart” from the often-overlooked final Dead studio album Built to Last, with Kadlecik singing in a slightly deeper tone that channeled the late-period Garcia. Weir then funked things up by taking lead vocals on a cover of the Otis Redding staple “Hard to Handle,” followed by Phil Lesh’s lone lead vocal turn of the night on “New Potato Caboose.” This fan favorite from the Dead’s second album, Anthem of the Sun, took the audience on a slow-paced psychedelic trip that combined with “Doin’ That Rag” paid homage to the band’s early years.

“New Potato” wove into what was probably the strongest segment of the night: a continuing jam consisting of “Estimated Prophet,” “Scarlet Begonias” and “Fire on the Mountain.” Highlighted with an intense light show in the background, these songs featured tight yet spontaneous playing and got the crowd in motion despite the oppressive temperatures.

Again displaying their knack for tempo shifts throughout a show, Furthur then sped things up with “King Solomon’s Marbles” before slowing down with the set closer, a hauntingly beautiful cover of the Beatles’ “Dear Prudence,” with Weir supplying raspily effective lead vocals counterbalanced by the high harmonies of backing vocalists Sunshine Becker and Jeff Pehrson.

The encore, “Liberty,” was originally the title track from a late 1980s Robert Hunter solo album and later became a feature of Grateful Dead concerts in the last year or two of the band’s run. Furthur has been occasionally playing it for a while but began including it in their sets more frequently during the “Arab Spring” uprising this year.

It’s also worth mentioning the second set featured a short, freeform instrumental which started out with drummer Joe Russo proving his chops for a few minutes before the rest of the band launched in with a southern-fried jam that included Allmanesque guitar flourishes from Weir and Kadlecik. Yet another unexpected nugget in a night where Furthur showed they are capable of throwing a few curveballs into their usual repertoire and maintaining their cool on even the hottest of evenings.