Midway through his traversal of Wagner’s 10 mature operas for PentaTone, we’ve learned this about Marek Janowski: The no-nonsense maestro puts clarity and detail above the saturated sound and expressive phrasing many conductors employ to capture these works’ mysticism and grandeur.

It’s an approach seems less than ideal for Tristan und Isolde, an opera filled with ambiguities whose fabric fairly ripples with expressions of erotic desire. But Janowski’s newly released March 2012 concert performance with the Rundfunk-Sinfonieorchester Berlin and its chorus turns out to be the best installment in the series to date, a study in canny pacing and dramatic shadings with a top-notch cast led by Nina Stemme and Stephen Gould.

Capturing the essence of Tristan is no simple feat. Though its tragic love story can be summarized in a few moments and provides little outward action, Wagner utilizes mysterious words and beguiling orchestral narration to flesh out the characters over four hours and transport listeners into their psyches. Performing the opera in concert, while not ideal, relieves the singers of having to act out the passions that collide with the tale’s ethical restraints and places the focus entirely on the sheer intensity of Wagner’s melodic lines and force of the music’s climaxes.

Though this reading may not be in the league of say, Wilhelm Furtwangler’s epic 1952 recording, Janowski admirably delivers the goods, efficiently stitching the waves of leading motifs into a flowing narrative while staying attentive to the opera’s constantly shifting moods. PentaTone’s fine SACD sound helps capture the charged nature of the drama and the acoustics of Berlin’s Philharmonie, vividly bringing out individual sections of the orchestra and effects such as the offstage brass in Acts 1 and 2.

Stemme’s performance should be reason enough to buy the set and reinforces her standing as the preeminent Isolde today. Her formidable yet burnished soprano is seamless through the registers, surging effortlessly upward during the Irish princess’ Act 1 narration and curse, then turning tender and sublime during the lengthy Act 2 duet “O sink hernieder,” when Tristan and Isolde praise night and death as the only sanctuaries for their love. Her Liebestod is radiant.

Overall, this is a more vocally secure performance than Stemme’s 2005 EMI recording with Placido Domingo, where she seemed to get swamped in spots by Antonio Pappano’s intense orchestral accompaniment. Janowski is an attentive partner, giving the work a strong sense of forward motion while almost always maintaining a proper balance between the orchestra and her voice.

Gould—who spent the first decade of his career touring in Phantom of the Opera and other musical theater productions—more than holds his own here, dispatching Tristan’s punishing autobiographical narrative in the first scene of Act 3 with precision and passion and sensitively shaping long phrases in his scenes with Stemme. His is maybe not the most beautiful or colorful voice, but a sturdy one with nice baritonal shadings. And though there are some hints of strain singing over the huge orchestra, one got the feeling he could have kept going long past Tristan’s expiration.

Baritone Johan Reuter stands out among the rest of the cast as a sympathetic and totally committed Kurwenal. Though his voice isn’t very big, it conveys authority and adds a human dimension to a character that too often recedes into the background. The light-voiced mezzo Michelle Breedt tries a little to hard to wring meaning out of each of Brangane’s lines in a performance that at times sounds like a lieder recital.

As King Marke, bass Kwangchul Youn easily matches the orchestra’s sonorities but sounds bland and a bit shaky in his confrontation with Tristan at the end of Act 2. Tenor Timothy Fallon makes an energetic young sailor.

Janowski’s reading clocks in at a relatively fleet three hours 45 minutes but never sounds rushed. He draws some of the warmest and heartfelt playing in the moving prelude to Act 3 with its poignant English horn solo, and shapes the act’s dramatic arc into a feverish climax with Isolde’s entrance. Though there’s no holding back in such big moments, Janowski maintains a sense of proportion and taste that really makes one really appreciate his artistry. The orchestra and chorus sound totally committed to his approach.

Listeners who found the conductor’s Lohengrin, Parsifal and Meistersinger little more than cooly competent will probably find this Tristan a revelation. Heading into Wagner’s centennial year, it also makes one look forward to his reading of the Ring operas that will cap this series.