Guaraná seeds contain roughly two to four times as much caffeine as coffee beans, though the soda itself has only a little.
Guaraná Antarctica is a bright, fruity soda flavored with guaraná, a caffeine-rich seed native to the Amazon that Indigenous Brazilians used long before it became a soft drink. It's sold in every corner bar, beach kiosk, and street-food stand nationwide, usually ice-cold.