Preheat oven to 350°F.
Grease the bottom of a straight sided tube pan (9.5 inches) and line with parchment paper cut into a circle to fit. Grease the sides, center tube, and parchment paper or spray with a non-stick cooking spray. Set aside.
Melt the butter and add to a large mixing bowl. Add the beer, sifted cocoa powder, and granulated sugar. Whisk until blended.
In a small mixing bowl combine the sour cream, eggs, and vanilla. Whisk until smooth.
While gently whisking the beer mixture, slowly pour the egg and sour cream mixture into the large mixing bowl.
Combine the flour, baking soda and salt. Fold the flour into the egg and beer mixture and whisk until blended.
Pour the batter into the greased and lined tube pan. Bake 45-50 minutes or until a wooden toothpick comes out with no raw dough - moist crumbs are okay.
Cool completely before removing from the pan and icing.