As a sommelier and brewer, I can confirm that a traditional Black Russian cocktail does not contain cola. The classic recipe calls for a combination of Kahlua, a coffee liqueur, and vodka. However, some variations of the Black Russian do incorporate cola to add a different twist to the drink.
When cola is added to a Black Russian, it serves multiple purposes. Firstly, it stretches out the drink, making it larger in volume. This can be useful if you prefer a longer-lasting cocktail or if you want to savor the flavors over a longer period of time.
Secondly, the addition of cola introduces bubbles to the drink. The carbonation from the cola creates a lively and effervescent texture, which can be refreshing and add a bit of excitement to the cocktail. The bubbles also help to lighten the overall mouthfeel of the drink.
Lastly, the unique flavor of cola is infused into the Black Russian when it is added. Cola has a distinct taste that combines sweetness, caramel notes, and a hint of citrus. When mixed with the rich and robust flavors of Kahlua and vodka, the cola adds a subtle layer of complexity to the cocktail.
Personally, I have experimented with adding cola to a Black Russian on several occasions. I found that it does indeed alter the drink in a pleasant way. The cola's sweetness and carbonation complement the coffee and vodka flavors, creating a more balanced and nuanced cocktail. It can be a great option for those who enjoy the taste of cola and want to try something different with their Black Russian.
While a traditional Black Russian cocktail does not contain cola, adding cola to the mix can enhance the drink by stretching it out, introducing bubbles, and infusing a unique cola flavor. It's a personal preference whether to include cola in your Black Russian, but it can certainly be a delightful variation to explore.