Some espresso blends include Robusta because it can add body, intensity, and thicker crema to the final cup. Its stronger structure helps espresso taste fuller and more pronounced, especially when paired with milk.
In many blends, Robusta is used in small amounts rather than as the dominant component. This allows roasters to balance Arabica's sweetness and aroma with Robusta's strength and texture, creating an espresso that feels richer and more substantial.