If you’ve ever spotted Coca-Cola bottles with bright yellow caps, you may have wondered whether they contain a different drink. These bottles are a special seasonal version of Coca-Cola produced for Passover, when certain ingredients traditionally used in standard products are avoided under Jewish dietary laws.

The yellow cap helps identify Coca-Cola that is certified Kosher for Passover. Standard Coca-Cola in the United States is generally sweetened with high-fructose corn syrup, while the Passover version is made with real sugar, typically cane sugar. Corn and other grains can be restricted during Passover, so the special formula is produced to meet the holiday’s dietary requirements.

The bottles are also marked with kosher certification, allowing consumers to distinguish them from regular Coca-Cola. The exact packaging and availability can vary by market and year, but the distinctive yellow cap has become a familiar seasonal sign for shoppers looking specifically for the Passover version.

Some people seek out these bottles even when they aren’t observing Passover because they prefer the taste of Coca-Cola made with real sugar. Fans often describe the flavor as different from versions sweetened with high-fructose corn syrup, although taste preferences naturally vary.

Yellow-capped Coca-Cola is typically available for a limited period around Passover and can be easier to find in areas with larger Jewish communities or at stores that specifically stock kosher products. So the unusual cap isn’t a secret flavor or a manufacturing mistake—it’s a simple way of identifying a seasonal Coca-Cola made to meet specific dietary requirements.