Matching the hypnotic flow of her best work, Lucinda Williams’ extraordinary releases have come in an unhurried fashion. Car Wheels on a Gravel Road survived a tortuous, six-year birth to become 1998’s most acclaimed recording, and 1992’s Sweet Old World was similarly fussed over. Essence is only the sixth release of a two-decade-plus career, but wrapping it in less than a year is likely an effort to put her doubting demons behind her. Yet by setting a pattern of overanalyzing every decision, she has also placed the bar impossibly high. As a result Essence seems lacking at first. The curious pacing starts at a crawl and throttles down from there; you’re five songs in before the rhythm section breaks much of a sweat. “Blue” moves so slowly that it tests your patience and seems nothing short of a love song to depression. “I Envy the Wind” and the childhood ode “Bus to Baton Rogue” both feel forced and unconvincing. And though a longtime Austin resident, her current Nashville tenure is starting to show, particularly in the grimace-guitar-squeals of Bo Ramsey. So what’s there to like? Everything else. Williams has let a relaxed edge emerge in her voice. Her words, even her very timbre, evoke longing in a way no one else can. “Broken Butterflies” and the smart kiss-off “Are You Down” (“Rain turns the dirt into mud/warm and messy/like your love”) direct a sharper edge at their victims, while “Lonely Girls” and “Out of Touch” find the perfect tone of tenderness. And the slow-boiling sexuality of the title track remains her strong suit. Few artists manage to work on such a consistently high plane. But with her newfound schedule, does twice as much Lucinda mean we risk losing the rare masterpiece? You do the math.