Saying no to bread worship

(Significance of yeast fermentation in pharaonic Egypt and Passover; July 2008)

The seder, or ritual Passover meal, is very rich in symbolism. The two most central symbols are probably the matzah and the sacrificial meal of lamb, which is most conspicuous today by its absence. An additional piece of matzah, the afikoman, has been eaten in place of the Paschal lamb since Jewish animal sacrifice ended with the destruction of the second temple in the year 70 CE.

The history of food processing sheds light on an interesting, but little-known parallel between the symbolisms of matzah and the Paschal lamb. Several of the classical commentators mention the idea that the lamb sacrifice was meant to express rejection of the idolatrous Egyptian practice of deifying sheep and other animals. Indeed, one can hardly find a museum exhibit or book of Egyptology that does not contain numerous paintings or carvings of animal-headed gods. Tying a lamb to the bedpost for three days before slaughtering it and smearing its blood on the doorframe left no doubt that the departing Jewish slaves had neither fear nor respect for the Egyptian pantheon.

In his commentary on the Haggadah, the manual for the seder, Rabbi Beryl Wein cites a book by H. E. Jacobs entitled Six Thousand Years of Bread. Basing his comments partly on this book, Rabbi Wein points out that the use of yeast to make risen breads originated in ancient Egypt. (Later, Egyptians and Mesopotamians learned to use such fermentations to make the first beers.) Perhaps because the leavening process was so poorly understood and mysterious, the Egyptians considered it mystical and divine. The importance of leavened bread to the imagination of pharaonic Egypt can be confirmed by a visit to the Metropolitan Museum of Art in New York, where models of triangular loaves, buried in the pyramids to nourish the departed, can be seen.

However, the rising of these early breads was much slower and less efficient than the rising of modern yeast dough. Relatively pure, efficient yeast cultures have only been available to bakers and brewers since the nineteenth century. Before that time, both commercial and home bakers collected wild yeasts from the surfaces of plant materials such as grape leaves. These undomesticated yeast strains were often inefficient as bread leavening agents. Some bakers maintained their own yeast cultures in a form similar to sourdough starter, a mixture of yeasts and bacteria grown in dough that nourishes these microorganisms and protects them from dehydration. This yeast culture is the leavening agent that Jews are forbidden to consume, own, or obtain benefit from during Passover. Early Egyptian yeast cultures were so inefficient that bread dough took three days to rise, a task accomplished by today’s well-bred yeasts in an hour or two. Home culturing of wild yeasts is still practiced in some neighboring cultures. For example, injera, a traditional Ethiopian bread, requires a three-day rising period when made in this way.

These facts provide an interesting perspective on the Exodus. Tethering a sheep for three days before slaughtering it and exhibiting its blood expressed faith in the one God who commanded this sacrifice, and rejection of Egyptian polytheism and superstitions about animal gods. In the same way, baking fresh dough into matzahs, rather than waiting three days for it to rise (or even longer for beer), showed that our ancestors had no need of the “god” responsible for the mysterious process of leavening.

NOTE: This essay is an excerpt from the popular Torah Flora live program “Three Mitzvot of Pesach.” For information about live Torah Flora programs, see Events or e-mail


  1. This is most interesting. Can you offer a source for the three day yeast fermentation process in ancient days? Certainly the Rabbinic discussions, which occur well before the 19th century, posit a much shorter time, although one might quibble about what you refer to as “rising” and their strictures on “leavened” which occurs as soon as little cracks appear in the dough.

  2. Myron, here are several interesting sources for the slow fermentation and rising of ancient breads. You will find some of them listed on the Resources page or I would start with Harold McGee’s classic food science book, On Food and Cooking. He also describes the making of injera, an Ethiopian bread that is still allowed to rise over a period of days due to the action of wild yeasts and the grain’s own enzymes. Another is Six Thousand Years of Bread, by H.E. Jacobs. A third book that provides some information about early bread making and how it originated alongside beer brewing is A History of the World in Six Glasses, by Tom Standage. For more of the Biblical background to this story, I would look at two books listed on my Resources page–Prof. Feliks’s Nature & Man in the Bible and Noga HaReuveni’s Nature in our Biblical Heritage.

    Regarding the Rabbinic discussions of dough fermentation taking place in 18 minutes, as you indicated, it is important to remember the context and agenda of those discussions, which is to determine the minimum possible time for at least the possibility for fermentation to begin, making the dough potentially chametz and invalid for Passover, not how long it should rise to produce a quality loaf. Mass production of concentrated cultured yeast began with the help of Louis Pasteur and others in the 1800s. Before that, a piece of dough from each batch of bread was kept as a starter for the next by both housewives and commercial bakers. It was common in a number of Old World Jewish communities for Gentile women to gather outside of synagogues on the night that Passover ended to sell pieces of starter dough to Jewish women on their way home to restart their own dough supply after the holiday ended.

    I hope that this information will be helpful.

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