Sift together flour, sugar, cocoa powder, salt, baking soda and baking powder in a large bowl.
In a separate medium to large bowl, whisk together milk oil, eggs, vanilla and Guinness.
Add wet ingredients to dry a bit at a time, mixing together completely.
Line your cupcake pans with liners and fill cups 2/3rd full. Bake for 22-25 minutes in a 350 degree oven.