Pesach is just 20 days away. Some of us are already deeply involved in planning seders and even beginning to stockpile food and drink that is kosher for Passover. Certainly the supermarket aisles in many communities are brimming with matzah and macaroons.

I am referring to Rabbi Tuvia Geffen, zichrono livrakha , may his memory be a blessing. We are all grateful to Rabbi Geffen, as I will explain. And believe me, it does relate to Pesach.

Today I want us to celebrate the significant accomplishment of a rabbi whose name you might not know. But you know what he did, even if you don't know he's the one who did it.

Rabbi Tuvia Geffen was born in Lithuania in 1870. He was educated in the renowned Slobodka yeshiva. In the wake of a pogrom, he immigrated to New York in 1903. He was 33 years old.

I learned about Rabbi Geffen's central accomplishment from a New York Times article about him. The article was written by Samuel G. Freedman. It appeared in Freedman's regular column called "On Religion." What I am going to tell you is based on that article.

Soon after arriving in Atlanta, Rabbi Geffen established Atlanta's first Hebrew school. He also had charge of the communal mikveh.

Seven years later, in 1910, he moved to Atlanta to become the rabbi of Shearith Israel. At that time Shearith Israel was a tiny and struggling Orthodox congregation. They met in the battered remnant of a Methodist church.

Starting in 1913, Rabbi Geffen was at the center of efforts to support Leo Frank. He was the Jewish superintendent of the National Pencil Company in Atlanta. A thirteen-year-old girl, Mary Phagan, an employee at the company's factory, was murdered there. The authorities charged Frank with the murder, though he protested his innocence.

Throughout this ordeal Rabbi Geffen not only supported Frank's cause but urged his congregants not to flee the South, despite their fear of violence by the Ku Klux Klan and evident public support for anti-Semitism.

Two years later, after Frank had exhausted all his appeals, Governor John Slaton commuted his sentence from death to life in prison. That decision aroused outrage from the community. A mob kidnapped Frank from the state prison and took him to Phagan's home town of Marietta, then lynched him.

At Passover in 1925, Rabbi Geffen spoke eloquently and presciently against Congress for passing immigration restrictions. He said that Congress had "slammed shut the gates of the country before the wanderers, the strangers, and those who walk in darkness from place to place."

As early as 1933, Rabbi Geffen warned about the Nazi regime in Germany.

Long before feminism, he advocated for Orthodox women who were being denied religious divorce decrees by vindictive husbands.

But all those achievements are not why I want you to know about Rabbi Geffen today, more than 40 years after his death. Instead, I want to honor today his least likely but perhaps most enduring contribution both to the Jewish people and to his adopted nation. Rabbi Geffen persuaded the Coca-Cola Company to change its formula so that Coke would be kosher for Passover.

Observant Jews of today will search supermarket shelves for those bottles of Coca-Cola with the telltale yellow cap bearing the Orthodox Union's certification. Even lovers of Coke who are not Jewish often will prefer the Coke that is kosher for Passover, because they think it tastes better, and they may be right, as I will explain. In any event, both Jews and the Coke lovers who are not Jewish owe a debt of gratitude to Rabbi Tuvia Geffen.

Rabbi Geffen had a typical long beard. He wore wire-rim glasses. He spoke Yiddish-inflected English. By all outward appearances, he belonged to the Old World.

Nevertheless, as a result of both geographical coincidence and his persistence, Rabbi Geffen was the person who caused the Coca-Cola closely-guarded secret formula to be changed so that we can buy kosher Coke. In fact, he went beyond making Coke kosher for Passover. He also solved the problem that Coke was not kosher for the rest of the year, either, until his intervention.

He issued a rabbinical ruling, a teshuva, on the subject, in 1935. That teshuva remains the standard to this day.

That ruling also did much more than solve a dietary problem. He issued his ruling a generation after the lynching of Leo Frank. A decade had passed since Congress barred the Golden Door. He acted in the midst of the early stages of Hitler's genocide. His act caused kosher Coke to serve as a powerful symbol of American Jewry's acceptance in the mainstream of American life.

Marcie Cohen Ferris is a professor of American studies at the University of North Carolina. She specializes in Jewish life in the South. She had this comment about the cultural significance of Rabbi Geffen's ruling in making Jews more accepted.

Rabbi Geffen really understood the importance of what he did. You couldn't live in any better place than the South to get it. Not to drink Coca-Cola was certainly to be considered un-American.

We can also consider the interplay of Jews and America from another angle. Rabbi Geffen's solution to the Coke problem was not to forget the kosher rules and melt into the melting pot. He also didn't attack the drinkers of Coke by criticizing the spiritual pollution of modernity in the form of a fizzy drink. More than half a century before our current era of cultural pluralism, Rabbi Geffen's approach was to work with the majority and persuade one of its leading companies to address the distinct needs of a minority.

A contemporary Orthodox rabbi, Adam Mintz, has written an essay on the subject of Rabbi Geffen and Coca-Cola. Rabbi Mintz said in that essay:

Struggling to find their place in a land that was often hostile to their religion, American Jews respected and appreciated rabbis who sought to include them within the Orthodox camp rather than simply condemn them as sinners. Of course his approach would not have been possible had he not felt confident in his powers of persuasion.

We can safely say, however, that this issue chose Rabbi Geffen rather than the other way around. As early as 1925, as the Orthodox authority in Coke's home city of Atlanta, Georgia, he was receiving questions from other rabbis who wanted to know from him whether Coca-Cola was kosher. Some rabbis had gone ahead and certified Coca-Cola as kosher even though they didn't know the secret formula. And many, many American Jews were drinking Coke regardless of whether it was kosher or not.

Rabbi Geffen explained in his teshuva what prompted him to try to make Coca-Cola kosher:

"Because it has become an insurmountable problem to induce the great majority of Jews to refrain from partaking of this drink," Rabbi Geffen wrote, "I have tried earnestly to find a method of permitting its usage. With the help of God, I have been able to uncover a pragmatic solution."

Rabbi Geffen had some significant earthly help, also, in the person of Harold Hirsch. He was not only a Jewish lawyer in Atlanta. He served as Coca-Cola's corporate lawyer. Through Harold Hirsch, Rabbi Geffen was permitted to enter that company's Holy of Holies and receive Coke's secret formula, after he promised to keep the secret.

When he studied the formula, the rabbi was able to identify the elements that rendered Coke treif during the bulk of the year. He found that one of the ingredients, glycerin, was produced from tallow of non-kosher beef. He convinced the company to substitute a vegetable-based glycerin.

That solved the problem for Coke all year except during Pesach. But Coke also included traces of alcohol derived from high fructose corn syrup. Corn syrup is made from corn, of course. And corn can be used to make bread. So corn is not kosher for Passover, and neither is corn syrup. And so, neither was Coke.

Rabbi Geffen had a solution. He and the Coca-Cola Company reached an agreement to substitute cane sugar or beet sugar in order to make Coca-Cola kosher for Passover.

When Rabbi Geffen wrote his teshuva he did not want to reveal any aspect of the secret formula. Rather, he disguised the names of the exact ingredients by using Hebrew euphemisms.

Kosher-for-Passover Coca-Cola is now produced under rabbinic supervision at bottling plants serving Jewish population centers in New York, Florida, Southern California and Houston, among other areas. A number of other major brands have followed Coke into the Passover market, including Dannon, Lipton, Pepsi and Tropicana. We can even buy today tequila and blintzes made without forbidden grains.

Rabbi Menachem Genack is the head of the Orthodox Union's kosher-certification program. He said, "It used to be that for Pesach you were limited to matzah and hard-boiled eggs. Now, I've got to tell you, I love those cheese blintzes."

And, whether devout Jews or otherwise, fans of Coca-Cola of all religious persuasions anticipate Passover for their own cultish reason. They find the taste much improved when Coke is made with cane or beet sugar rather than corn syrup.

Moshe Feder is an editor of science-fiction and fantasy books. Last year at this time he traveled to six supermarkets from his home in Queens in search of kosher Coke. He finally found and bought four two-liter bottles. The subject of his quest happened to come up at a seder he attended a couple of weeks later. The host was Jewish, but he had never heard about the difference between Coke and Passover Coke. There were two Roman Catholic guests there, however. Mr. Feder reported that those two knew all about Passover Coke, and loved it.

Rabbi Geffen, of blessed memory, who could have guessed your work would turn out to have such an ecumenical result?