3 allspice berries
1 star anise
¼ teaspoon each pink peppercorn, gentian root, wild cherry bark, lemon peel, sarsaparilla
150 mL vodka

Combine it all. Let it sit for 3 weeks. Strain.

Source: http://harmonioushomestead.com/2012/11/19/homemade-bitters-recipe/