Unapologetically traditional, Cantor Jack Mendelson relishes a bit of shmaltz, and he wants others to learn to love it. Plus, he says, there’s too much “white bread” in contemporary synagogue music. How about pumpernickel for a change?

A star-quality soloist with a voice that reverberates in performance halls as well as synagogues, Mendelson, 68, is a stubborn champion of the traditional synagogue music now out of favor in liberal synagogues, music he has taught to Reform and Conservative cantorial students for more than 25 years.

Mendelson, whose life and work has been the subject of several documentaries, will be at Congregation Beth Am in Los Altos Hills on Saturday, Jan. 31 regaling attendees with songs and stories of his boyhood as a “yeshiva kid” in 1950s-era Brooklyn.

He and his brother, Solomon, were groomed for the cantorate ­as young children, trotted out to sing for the noshers in their father’s deli in Borough Park, the heavily Jewish neighborhood in Brooklyn. Meanwhile their mother, “a huge fan of chazzanut,” or Eastern European-inspired cantorial music, shlepped her sons all over Brooklyn to hear the last of the legendary European-trained chazzans, whose emotion-filled melodies caused congregants to tremble.

Cantor Jack Mendelson

Today, he said, the trend is for the cantor to be a song leader. But Mendelson, a sonorous tenor, prefers to see himself as a “prayer leader.”

“What I always tried to do in my cantorial life is make the text come alive in an appropriate way, respecting what the text is saying,” he says in a phone interview from his home in White Plains, New York, where he recently retired as full-time cantor of the Conservative Temple Israel Center.

Jewish liturgical music shouldn’t always be upbeat, he emphasizes. “You can’t have it just happy, happy, happy. You have to have pathos, you have to have sad, because the message in the text is not always sweet and beautiful.”

His mentor, Cantor Moshe Ganchoff — called the last great master from the golden age of chazzanut — “used to say [his] favorite singer was Maria Callas, because she knew how to sing an ugly tune when it was necessary.”

Music is in the Mendelson DNA, past and present. Both he and his brother became cantors, as did their uncle. His wife, Fredda Mendelson, is cantor emerita at Westchester’s Larchmont Temple, and their son, Daniel, is a cantor at Congregation B’nai Sholom-Beth David in Rockville Centre, Long Island.

The three Mendelsons — Jack, Fredda and Daniel  — all sing opera as well. Jack Mendelson, who graduated from the American Opera Center at Juilliard, calls himself  “a sucker for opera, because I’m a crybaby.”

But becoming a cantor was no easy task for a high school dropout. He ruled out becoming an Orthodox cantor, as there were few positions available. But when he looked into the Conservative Jewish Theological Seminary, he was told to complete his undergraduate degree first, preferably at Columbia. That was a nonstarter.

“I was a horrible student,” says Mendelson, who earned his high school diploma at night school. “If I had to take secular courses at Columbia, I could never have passed.” However, the Reform movement’s Hebrew Union College let him complete his undergraduate courses in-house.

Ordained in 1970, he did so well that he trains cantorial students at both HUC and JTS, teaching them “Fraygish,” technically the Phrygian dominant scale, with flatted seconds and sixths, that gives Eastern European music its soul. Think “Ahavah Rabah,” or “Miserlou.”

One of his students was Beth Am’s Cantor Lauren Bandman, who was “like the pillar of her class. She was the best.”

“Cantor Mendelson is truly a master cantor,” Bandman wrote, “with superb talent, an incredible voice, incomparable knowledge, and a delightful presence that fills the room with joy and fun.” As a teacher, she added, he has connected “generations of new cantors to the great chazzanim.”

He also connected with the late Debbie Friedman, and their work together is captured in the 2004 documentary “A Journey of Spirit.” His own story was chronicled in another documentary, “A Cantor’s Tale,” featured in the San Francisco Jewish Film Festival in 2005.

Initially, Mendelson and Friedman had a friendly rivalry. In a nutshell, their styles were 180 degrees apart. But then they played music together.

“She taught me how to laugh. She was a hoot. I’d work on Fraygish with her. She’d work on my guitar,” he said. “Before I worked with her, I didn’t think people who sang her songs were really davening. But then I saw it. She was davening.”

In retrospect, Mendelson said, his problem with folk-inspired synagogue music was that it has taken over, particularly in the Reform movement.

“It’s becoming a happy, clappy generation, but like everything else it’s circular,” he says. “It’s changed to that, but it will change back. The classical cantorial style is coming to life, waiting in the wings.”

“The Cantor’s Couch” with Jack Mendelson, 7:30 p.m. Saturday, Jan. 31 at Congregation Beth Am, 26790 Arastradero Road, Los Altos Hills. Free. www.betham.org. Also “Hazanos: Jack Mendelson’s World of Cantorial Music,” 8 p.m. March 7 at Temple Sinai, 2808 Summit St., Oakland. $22-$28. www.jewishmusicfestival.org/events/hazanos