Cream shortening; gradually add sugar, beating until light and fluffy. Add eggs, one at a time, beating well after each addition. Add melted chocolate, mixing well.
Dissolve coffee granules in 1/2 cup water; stir well, and set aside.
Combine flour, salt, cream of tartar, and soda; gradually add to chocolate mixture alternately with coffee mixture, beginning and ending with flour mixture. Mix well after each addition. Stir in vanilla.
Pour batter into a waxed paper-lined and greased 9- x 5- x 3-inch loaf pan. Bake at 325° for 1 hour and 15 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes; remove to wire rack, and cool loaf completely.