Cream shortening, add sugar gradually, then cream until fluffy. Blend in well-beaten eggs. Mix cocoa, red coloring and hot coffee to form a smooth paste. Blend into creamed mixture (cocoa mixture tends to thicken upon standing). Sift flour, salt and soda together, and add to creamed mixture alternately with sour milk. Blend in vanilla. Pour into well-greased and floured pan (8 inch square, 2 1/2 inches deep or 2-8 inch layers, 1 1/4 inches deep). Bake in 350° oven: square pan, 70 minutes; layer pans, 40-45 minutes.