Heat oven to 400℉/200℃.
Line a sheet pan with parchment paper. Set aside.
While the oven is heating, reduce the beer.
Pour the entire 11.2 ounce bottle into a small saucepan.
Bring to a simmer over medium low heat. Do not boil. (As the beer gets hot, it will foam a lot. As it starts to cook, the foam will die down.)
Start stirring and keep it stirred until it has reduced by ½, about 15 minutes. (It should measure ¾ cup, which is the exact amount you need.) Be careful. It can burn quickly. Set aside to cool.
In a large bowl, stir flour, cocoa powder, brown sugar, salt, baking soda, and chocolate chips together.
Add reduced beer, honey, buttermilk, and butter.
Stir until it comes together as a dough.
Turn out onto a floured surface.
Form into a ball.
Place on prepared pan.
Using a sharp knife, cut an x on top of the loaf. The cuts should be halfway through the bread.
Bake for 45 minutes, or until bread tests done.