Coca-Cola’s yellow caps are back — what they mean and why they’re compared to Mexican Coke

Every spring, Coca-Cola bottles look a little different, sporting a bright yellow cap rather than the usual red. While social media has compared the seasonal product to Mexican Coke, which uses cane sugar instead of high-fructose corn syrup, the origin of the cap change traces back to a rabbi in Atlanta, Georgia.

Rabbi Tobias Geffen, who led Atlanta's Orthodox Jewish community and served as the rabbi of Congregation Shearith Israel, is credited with making the iconic beverage kosher and...