Jonathan Cohen is no ordinary conductor. He doesn’t flamboyantly wave a baton at his players. He doesn’t strike melodramatic poses signaling his emotional involvement with music.

Cohen has a quieter, more nuanced way. Concertgoers will find him seated at a harpsichord with his back to the audience, swaying gently to the rhythms. They occasionally see him nod or lift an arm to cue an entry. A listener can’t help but wonder — is he doing much of anything at all?

But Cohen’s gentle guidance has proved a blessing for the St. Paul Chamber Orchestra. It’s been five years since Cohen first came to Minnesota to lead the SPCO’s performances of Handel’s “Messiah.” It was “a spectacular debut,” remembered Kyu-Young Kim, the SPCO’s principal violin and artistic director. “He instantly connected with the players. It was especially exciting as we’d just come back from the lockout, and it was the first ‘Messiah’ we’d done in many years.”

Cohen returns to the SPCO Nov. 2-4 to lead three performances of Bach’s “Saint John Passion,” a masterpiece of baroque choral music describing the events leading to Christ’s crucifixion.

The SPCO has a long history of successfully playing baroque music under conductors such as Nicholas McGegan, Christopher Hogwood and Pinchas Zukerman. But recent decades saw the colonization of early music by specialist ensembles playing historical instruments, using techniques appropriate to the music’s historic origins. That frequently sidelined orchestras such as the SPCO, with many groups abandoning Bach, Handel and Vi­valdi entirely.

But with Cohen onboard as an artistic partner since 2016, Kim thinks the SPCO can reclaim baroque repertoire for the modern chamber orchestra. Cohen has “that perfect mix of understanding firmly how historical performance works, but never being didactic about it,” Kim observed. “His quickness of intellect is staggering.”

Although he is a musician of wide sympathies, Cohen’s specialty is the baroque and early classical period. In addition to running his own early music group Arcangelo in England, he serves as associate conductor of France’s storied Les Arts Florissants ensemble. And he just took over as music director of Quebec’s Les Violons du Roy.

Despite the busy schedule, Cohen remains excited about working with the SPCO. “I find the orchestra enormously welcoming,” Cohen said by phone from London last month. “Very open — and very interested in wanting to go deeper into the style of early music.”

In his first two seasons as an official SPCO artistic partner, Cohen has performed music by a wide range of composers including Avison, Zelenka, Locatelli, Pergolesi and Haydn. He finds that SPCO musicians are good at the subtle stylistic tweaking required to catch the flavor of these various composers. “The SPCO has a strong tradition of doing baroque music, so it’s not as if you’re going into a large symphony orchestra that’s never done Bach before,” Cohen said. “You already start on a very high level of technical ability.”

There’s still plenty of work for rehearsals, though. A cellist by training, Cohen recently singled out the way stringed instruments are used in baroque music. “In later, more romantic music there’s more of an emphasis on expression in the left hand,” he explained, referring to the hand used for pressing strings on the fingerboard. “In earlier styles it’s really about a very sophisticated use of the bow, held in the right hand — the speed and pressure of the bow, to find a lovely, sweeping sound.”

He recently coaxed three SPCO musicians into removing the steel strings from their instruments, fitting them instead with gut strings used in the baroque period. Adding his cello to the mix, Cohen led a very special SPCO performance of Haydn’s “The Seven Last Words of Christ” last spring. There was a certain tenderness and intimacy facilitated by the mellow, soft-spoken qualities of gut stringing.

The current trend is using smaller numbers of singers for Bach’s choral works — the SPCO used just eight voices for its performance of “Saint Matthew Passion” a few years ago. But for “Saint John Passion,” Cohen and the SPCO will partner with Twin Cities choir the Singers. With a team of soloists including counter-tenor Tim Mead and soprano Joélle Harvey, the choir will total more than 70 vocalists.

“The Saint John Passion is an incredibly dramatic and monumental work, one of Bach’s greatest,” Cohen explained. “The choral interventions and interjections are very powerful, and I want to really bring the chorus into the fray.

“I think these very majestic works of Bach benefit from reasonably large forces.”

And Cohen will be one of those forces, mapping out harmonies on his harpsichord or gesturing to shape the singers’ phrasing. His demeanor may be unassuming, but his quiet scholarship and collegiality practically guarantee a concert of musical excellence.

Terry Blain is a freelance classical music critic for the Star Tribune. Reach him at artsblain@gmail.com.