Amish Friendship Bread. The discoloration only occured on the botton 1/2 of the loaf. The loaf did not exceed more than 3/4 the height of the loaf pan. I used a silicon pan, plastic bowls & spatulas. No stainless steel or other metal utensils were used. The "starter" batter (reportedly started by the Amish) requires 6 days of fermenting then you add milk, sugar and flour and allow it to ferment for another 4 days. On day 10 the regular ingredients of eggs (whole), oil, sugar, flour, baking soda, baking powder, salt and vanilla are added. I also added cocoa. What would cause this odd discoloration? Thanks !