Gather the ingredients for the Caribou Lou cocktail: light rum, coconut rum, pineapple juice, and optionally, simple syrup or grenadine for sweetness.
Choose a good-quality light rum as the base. The light rum provides a clean and neutral foundation for the cocktail.
Add coconut rum to bring a tropical and sweet coconut flavor to the mix. This ingredient adds richness and complements the pineapple juice.
Use fresh or high-quality pineapple juice to infuse the cocktail with a sweet and tangy tropical taste. Consider fresh pineapple chunks or a pineapple garnish for added visual appeal.
Depending on your sweetness preference, consider adding a touch of simple syrup or grenadine. Adjust the sweetness to your liking, keeping in mind the natural sweetness of the pineapple juice.
Balance the proportions of the ingredients for a harmonious blend. A classic ratio is 3 parts pineapple juice, 2 parts coconut rum, and 1 part light rum.
Combine the ingredients in a shaker with ice and shake well. This helps chill the ingredients and allows the flavors to meld.
Strain the mixture into a glass filled with ice. Garnish with a pineapple wedge or slice for a tropical touch. Optionally, you can rim the glass with sugar for an extra sweet kick.