So just like it says, let's imagine drinks made to represent the 18 Primarchs of the Imperium, based on their personality/style. Probably should use only ingestable, desirable ingredients (looking at you Perturabo) but who's to say what is legal/illegal? (Fulgrim we still good)

One poor example, feel free to override:

Vulkan (Salamanders)
2 parts Absinthe
1 part Coffee Liquor
Light on fire