Mix and sift the first four ingredients. Make a well and add the oil, water, egg yolks, sourdough starter, vanilla and lemon juice. Beat until smooth. Now add the cream of tarter to the egg whites. beat the whites until well blended. Be slure to fold very gently. Turn into an ungreased 23 cm tube pan. Bake for 1 hour in a 160ºC oven. Cake should spring back when touched with finger. Immediately turn pan upside down placing tube over neck of bottle. Let hang to cool. Loosen with spatula to remove from pan. From Pat's Sourdough and Favorite Recipes ISBN# 0-9625098-1-7