In a 2023 interview with The Hollywood Reporter, Pablo Larraín spoke about the origin of the idea of vampires making blood smoothies: "Well, it's a joke. I don't know ... every time I go to L.A., there are all these people making smoothies out of anything and everything. (Laughs.) And that became a fashion everywhere - it spread from California to everywhere. So, we thought that instead of having the vampires do the classical neck bite and sucking the blood and all that, this smoothie thing would be a funny idea and an interesting political comment, too - to open the chest of someone and take out their heart and put it into a blender. You know, the vampires are very eloquent and particular in their motivations."
The hearts were made out of jello and new ones were made each week to ensure their freshness. The blood was colored blue to look better in black and white.
Gloria Munchmeyer and Catalina Guerra are real life mother and daughter playing mother and daughter in El Conde.