The Real Thing: How Coke Became Kosher

Detail from Coca-Cola ad, 1951. (Courtesy the Coca-Cola Company)

Detail from Coca-Cola ad, 1951. (Courtesy the Coca-Cola Company)

In the early 1930s Tobias Geffen, an Orthodox rabbi, began to receive a steady stream of letters from rabbis across the United States asking whether Coca-Cola was kosher. Coke was a popular beverage among Jews, and rabbis were worried. Since Coca-Cola was headquartered in Atlanta, where Geffen lived, he was essentially deputized by other rabbis to investigate. Rabbi Geffen did indeed discover a problem, a nonkosher ingredient present in Coke as well as in many other foods and beverages.

Today, about 40% to 50% of the items in a conventional U.S. supermarket are certified kosher by Orthodox rabbis. Yet there are at most one million observant Jews in a country of over 300 million people. With these numbers how did kosher products become so prevalent, and why do so many American businesses make food to accommodate kosher requirements? The story of how Coke became kosher helps unravel this paradox.

Rule of Law

The rules about kosher food go back to antiquity. Early oral traditions were codified in the Babylonian Talmud in the sixth century CE and then drawn together succinctly in the 16th-century Shulchan Aruch of Rabbi Joseph Karo. In and around these major documents generations upon generations of rabbis have woven a complex, sophisticated body of law governing food consumption by Jews. Separation between acceptable and unacceptable foods provides the core concept. Certain kinds of livestock, such as pigs, can never be kosher, while permissible types of animals, like cattle and chickens, must be slaughtered properly and inspected to determine whether they meet demanding kosher requirements. Kosher meat must also remain separate from foods classified in kosher law as “milk,” which includes cheese. In addition to the categories of milk and meat, kosher law provides for a third category, called parve, or neutral, that can be eaten with both of the other categories.

Some of these classifications might seem odd and arbitrary: fish and eggs, for example, are parve, even though both come from living creatures. Then, while insects are never kosher, honey, which is the product of an insect, is both kosher and parve; yet for milk to be kosher, it must come from an animal that is acceptable for observant Jews to eat. Behind these seemingly arbitrary classifications lie over a thousand years of debate among rabbis across Europe and the Middle East.

This sophisticated kosher law, developed over two millennia, has been profoundly challenged in the last 100 years by our modern food system. Processed food disrupted the stable categories on which kosher law was based through the inclusion of ingredients intended to make these products taste better, look attractive, and last longer. Manufacturers never identified the source of these ingredients, and many were included in such small quantities that they were not even listed on labels. How then to determine whether these new processed foods were kosher?

The rigid categories prescribed by kosher law were no longer self-evident in modern food, and rabbis schooled in pre-industrial Jewish law needed to figure out how to extend those principles to 20th-century conditions. They needed not only to apply kosher law to contemporary food manufacturing but also to ask American food manufacturers to accommodate kosher rules in the manufacturing process.

Out of these efforts came a new body of thought and practice that can be termed “kosher chemistry.” The sophisticated application of chemistry has made many contemporary foods that once were off limits acceptable to observant Jews. Much of the thanks goes to kosher chemists trained in theology and science, who successfully merged what might seem to be utterly opposed systems of thought.