The gritty ferocity at the essence of Muddy Ruckus’ sound is what’s made me a fan since the band formed in 2014.

I dare say that “Vacationland,” their fourth album which comes out on Friday, is the best thing they’ve done.

The South Portland-based Americana duo is Erika Stahl (vocals, drums, percussion) and Ryan Flaherty (vocals, guitar, keys, banjo).

Don’t think for a moment that the other three albums aren’t worthy of your ears because they certainly are but, wow, “Vacationland” is a cut above. From the lyrics and arrangements to the overall production, the already solid and established band has hit its stride in a huge way.

With ritualistic, almost tribal percussion from Stahl, the opening track “Pleasuring Ground” had my attention instantaneously. Add to that some bolts of Flaherty’s guitar and Stahl’s chant-like repetition of the line “devil came up,” the track is riveting and haunting. But that’s not all. There’s also some audio taken from a 1950s National Parks travel commercial. “The pleasuring ground for the benefit and the enjoyment of the people” is a line from what sounds like the guy who narrated every nature or science film that any of us ever saw in elementary school.

Without taking a breath, the album slides into “Long Time” featuring special guest James Montgomery on harmonica. Flaherty spits fire with lines that mention the devil and the apocalypse. “I’m gonna beat my chest till my heart falls out/’Cause I know a little evil won’t do without.” I have zero doubt he means it. The track is pure fire.

I’m also compelled to mention “Desert Neptune,” a slower but still upbeat tempo tune with Flaherty and Stahl singing together. A thumping bass line runs throughout making the song stick to the listener’s ribs. “It’ll be all right,” the pair repeats several times.

The album closes with the instrumental track “Dog Daze” featuring Dana Colley, an original member of Boston alternative band Morphine, on saxophone. Stahl and Flaherty met Colley over the past year and a half when Muddy Ruckus and Colley’s current band, Vapors of Morphine, shared billing at gigs around New England. When Colley heard an early version of “Dog Daze,” he loved it so much he sent the band a sax track to add to it. “For us, his playing on that track really completed the album with magic so we kept it as is with no lyrics,” said Stahl. At just under eight minutes, the track is tremendous.

I asked Stahl if “Vacationland” had any running themes because I was picking up on something I couldn’t quite put my finger on. “Awareness, maybe, and I think the songs have a critical yet humorous message on societal subjects as well,” she said.

Ultimately, though, Stahl said it’s up to the listener to decipher the meaning, but she strongly encourages people to listen all the way through. “It actually makes more sense if you listen to it that way, as opposed to one track at a time.” She and Flaherty paid close attention to the spacing between tracks and the sequencing of the 14 songs. “The album takes you down the lane, and at the end with ‘Dog Daze,’ there’s something there to meet you, perhaps a call for what will be, perhaps something that might bring you full circle to the beginning of the album again, like a snake eating its tail.”

Stahl continued.

“Our mindset was to create a body of work that represents our music evolution, and we wanted to capture the rawness of our live performance and make an album.”

“Vacationland,” Stahl said, is meant to take the listener on a journey. “We knew we wanted to rock out and just get all the demons out through our instruments and introduce the psychedelic vibe we’d been getting more at our shows.”

She and Flaherty, who are a couple, made the album by getting up every day for three weeks in January of last year and jamming together, recording every session. “In the end, we had about 30 rough songs and continued to work on 14 that naturally seemed to weave a tapestry and ultimately became ‘Vacationland.’ ”

Incredibly, most of the songs were written on the spot. “We mostly came up with words on the fly and then jotted them down in our notebook. It was all very in the moment with no pressure or judgment.”

Stahl also wanted to share something personal about her health.

Three years ago, she was on life support through dialysis because of a deadly kidney disease. She had a kidney transplant on May 26, 2020. “Three years later, to the day, we’re releasing our most important and relevant body of work into the world,” she said. “I couldn’t be more proud or more grateful and am truly excited to share ‘Vacationland.’ ”

Muddy Ruckus will be performing at the Resurgam Music and Arts Festival in Portland on June 11 at Ocean Gateway and surrounding areas. You can also see them July 7 at the Summer Sunsets Concert series at Thompson’s Point. Head to the tour page at muddyruckus.com for other Maine dates.

“Vacationland” will be available on streaming platforms on Friday. You can also purchase a digital album or physical CD at muddyruckus.com.

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