Crack a dense volume of the comprehensive "Book of Jewish Knowledge" or the "Encyclopedia Judaica" and you still won't know anything about one of Judaism's four main traditions.

Ashkenazi, Ethiopian, Sephardi — all will be described in varying degrees of small-print detail. But you won't learn anything about the now-obscure traditions of Mizrahi Jews.

Unless, of course, you happen to attend Rosh Hashanah services at the Aquarian Minyan this year.

For the first time, the Berkeley-based Jewish Renewal group is conducting a Mizrahi-style service and seder on Saturday, Sept. 14, the second night of the High Holy Days. The event takes place at John Hinkel Park in Berkeley.

Although less than five percent of the Berkeley congregation's members are Mizrahi — defined as indigenous Middle Eastern and North African Jews — service coordinator and cantorial soloist Naomi Winiwarter says including Jewish traditions from around the world "broadens everybody's mind. It's the kind of thing where everybody benefits."

What's the difference between Mizrahi and Sephardi? Service co-leader Loolwa Khazzoom, 27, a Mizrahi Jew of Iraqi descent, frequently fields such questions while teaching workshops about her culture and leading services around the Bay Area.

According to Khazzoom ("It's a Judeo-Arabic name; people always ask"), the term "Mizrahi" refers to Jews who remained in the Middle East or migrated to neighboring countries. Sephardim, on the other hand, are Jews who were expelled from Spain in 1492, many of whom eventually settled in the Middle East.

If there was a large enough group of Sephardi settlers, as in countries like Morocco and Iran, they tended to preserve their Spanish heritage, building schools and synagogues of their own. In countries like Iran and Iraq, however, Sephardim blended with the pre-existing Mizrahi culture.

"There wasn't enough critical mass to preserve the Sephardic culture" in those areas, says Khazzoom, explaining why Sephardi and Mizrahi cultures are not exactly synonymous, but have much in common.

Jews who attend Saturday's service will hear "new tunes, different passages and a different order" of prayers. The most striking difference will be a 30-minute Mizrahi-style seder after the service, in which pomegranates, leeks, squash and other fruits and vegetables will be blessed.

The Renewal movement, says Khazzoom, is "eager and excited about everything I have to teach." This month, the Berkeley-based writer and musician began introducing Mizrahi customs like drumming, chanting and meditation at a packed Shabbat service at the Aquarian Minyan.

"It is in the spirit of Jewish Renewal to try and access all kinds of wisdom and knowledge," says the congregation's shomer, or guardian, Marty Potrop. "We've always had diverse and eclectic portions of services. It's a welcoming to Jews from different backgrounds."

The group will also hold a "movement-based" service Sunday after the new year with at least three conga drummers, Potrop adds.

But while Khazzoom appreciates the congregation's all-inclusive attitude toward Jewish traditions, it is her own heritage that she is desperate to pass on.

From 1948 to 1950, almost the entire Mizrahi community left their home countries in the Middle East. Their property was confiscated and their communities decimated. Khazzoom fears that in the next two decades, the generation of Jews who left Arab countries will die out, and with them the Mizrahi traditions Khazzoom remembers from her childhood.

That's why she and the leaders of the Aquarian Minyan will be starting the new year with ancient rituals that have already disappeared from the pages of most Jewish history books.