To make the sorbet syrup, combine water with the sugar, tapioca starch, corn and syrup in a small saucepan over medium to medium-high heat.
Stir continuously for about 8-11 minutes until the mixture just starts to boil (do not allow it to come to a full boil) Once the texture of the sugar syrup becomes thicker and viscous (or once it hits 212 degrees if you are using a thermometer) immediately take it off the heat.
Place it in a container. Let the sorbet syrup cool to room temperature then refrigerate for a minimum of 4 hours to a maximum of 24 hours.
To make the cocoa cream, put the cocoa powder in a mixer fitted with the whisk attachment. Combine the remaining ingredients in small saucepan. Bring to a boil over medium-high heat. Stir occasionally. As soon as the mixture reaches a boil (or 212 degrees on a candy thermometer) immediately pour it into the mixer.
Start on low for 30 seconds then mix on high until the cocoa cream is thick and completely cool When you touch the sides of the bowl it should be close to room temperature. Cover and refrigerate.
Thoroughly combine the sorbet syrup, cocoa cream, and water with an immersion blender or in a regular blender.
Process in your ice cream maker according to the manufacturer’s instructions.
The sorbet is finished when it reaches the consistency of soft serve ice cream (about 20-30 minutes in most machines)
Scoop into a container, place a piece of plastic wrap or parchment paper on the surface and freeze until firm (2-4 hours minimum)