In a Colorado Bulldog, which ingredient is used to fill the glass?

In a Colorado Bulldog, the main filling ingredient that is used to top off the drink is Coke. This beverage is a playful twist on the classic White Russian, combining vodka, coffee liqueur, and cream or milk. The addition of Coke gives the Colorado Bulldog its characteristic flavor profile, enhancing the sweetness and providing a fizzy contrast to the creamy components.

The other options, such as ginger ale, soda water, and pineapple juice, are not traditionally used in this cocktail and wouldn't provide the same taste or texture that Coke brings to the drink. Soda water, for example, would dilute the richness without adding any complementary flavor, and ginger ale would introduce a spiciness that is not typical for this particular cocktail. Pineapple juice, on the other hand, would create a completely different flavor profile, leaning more toward tropical rather than the classic creamy and coffee notes of the Colorado Bulldog. Therefore, the correct choice of Coke is what defines this drink's identity.