Coke is only made specially for Passover -- at which time it uses cane sugar (not beet sugar).

Coke is kosher all year long but has this additional requirement during Passover. If you live in a city which has a fair-sized Jewish population you will find "Kosher for Passover" Coke in every supermarket, at the usual prices, for about two weeks before Passover and until the stock runs out after the holiday.