Herman cake

Herman cake (often called simply Herman) is a 'friendship cake', similar to the Amish Friendship Bread, for which the ingredients are passed from person to person (like a chain letter) and which continues to grow as it contains yeast and lactic acid bacteria. One starter can, in theory, last indefinitely. The other ingredients for the mixture are milk, sugar, flour and warm water. They became popular in the 1970s.

Herman sits on a worktop for ten days and is not refrigerated. Due to the amount of yeast that it contains it smells distinctly of beer. The Herman cake can 'breathe' when covered loosely with a tea-towel and left out on the worktop and stirred occasionally. This 'breathing' occurs because of the yeast in the Herman cake, and the cake mixture frequently bubbles.

When someone receives Herman from a friend, "he" will be presented in a small jar or plastic tub along with a set of instructions to guide them through the next ten days with the Herman cake mixture. After four days additional ingredients are added and stirred, and again after another four days. On the ninth day, Herman is divided into equal parts (four or five) and all but one of these parts are passed along to friends. The last part is kept and on the tenth day is cooked. Many ingredients can be added to Herman before the procedure of cooking the Herman cake. These ingredients can vary from eggs, cinnamon, apples, chocolate, and cherries to make Herman sweet or olives and sun-dried tomatoes for a savoury taste.

The German magazine Stern noted the resurgence in popularity of 'Hermann Teig' in Germany in the early 2000s - including the publication of a book by Dr. Oetker titled "Backen mit Hermann und Siegfried" - and commented on the similarity to another food trend: Kombucha, a fermented sweetened tea.