Fermentation and Pesach

*This article also appears in the Pesach issue of SoulWise Magazine.

Pesach is the one holiday on which Jews are required to become obsessed with food. This is actually a unique opportunity, since as modern Americans we usually do not have to think about where our food comes from or the far-reaching effects of our food choices. For instance, when I buy a hamburger, I don’t think about how the grain which fed the cow was grown on a vast monoculture farm using synthetic fertilizers. I don’t dwell on how the runoff from these fertilizers and the waste from the cow farm are creating an oceanic dead zone the size of New Jersey off the coast of Texas (http://serc.carleton.edu/microbelife/topics/deadzone/). I don’t even want to think about how my hamburger bun is made from those same grains. In short, most of us don’t usually analyze our food choices.

Which brings us back to Pesach.

On Pesach we are commanded not to eat any leavened bread or even to own any leaven (Shemos 12:15). Some people don’t eat any processed food during Pesach for fear that a small amount of leaven might have inadvertently entered the food production process.

But what is leaven exactly? The leaven of Pesach is yesteryear’s yeast, or as Henry David Thoreau described it in Walden, “[T]he soul of bread, the spiritus which fills its cellular tissue.” (Thoreau, Henry David. Walden and Civil Disobedience, Harper and Row 1965, p. 46) More accurately, leaven is yeast and bacteria in the form of a wet, bubbly mixture of flour and water used to make traditional leavened bread, or what we today refer to as sourdough. Coincidentally, the ancient Hebrew word for leaven is “se’or,” which sounds very similar to the word “sour.”

However, it is interesting that the yeast which ferments dough into leavened bread is basically the same yeast that turns grape juice into wine. Yet leavened bread is forbidden during Pesach, while fermented grape juice (i.e. wine) is an essential element of the Pesach Seder. (Indeed, the consequence of eating leavened bread during Pesach is kares, while drinking fermented grape juice at the Seder is a mitzvah d'rabanan.)

As an avid fermentation hobbyist, having a deeper understanding of bread and wine helps me understand this difference. Leaven is constantly bubbling as the yeast within it metabolizes the simple sugars in the mixture into carbon dioxide. Bread dough holds in these bubbles, and this is what causes bread to rise. On Pesach, we approach this air-filled bread as a metaphor for our own egos, while the flat matzah represents humility. There is a well-known phrase from the opening of Koheles: “Vanity of vanities, all is vanity.” (1:2) In Hebrew, the word for vanity (hevel) also means breath or breeze, emphasizing the connection between vanity and airiness. On Passover, we try to rid ourselves completely of any self-serving ego.

On the other hand, the winemaking process is a process of refinement. Yeast produces carbon dioxide bubbles during the wine fermentation process as well, but those bubbles escape. What remains is a cultured drink, much more complex and refined than the original grape juice. For this reason, our sages teach that the four glasses of wine we drink at the Pesach Seder are in memory of the four phrases of redemption that G-d used when taking us out of Egypt. Out of these four phrases, wine is especially connected to the fourth when G-d said, “I will take you to Me as a People.” The fulfillment of this level of redemption only came about at the giving of the Torah at Mount Sinai, an event for which we had to prepare and refine ourselves.

Paradoxically, the same yeast affects both the bread and the wine, but engenders a totally different change. And perhaps this is the message. Our sages teach that we have a powerful energy within us, which naturally pushes us in the direction it wishes to go. If we feed into it, we end up with a bloated ego. If, on the other hand, we use this energy for our own self-refinement, we develop fine character traits and we merit that the Torah should be given to each one of us personally.

This message is fitting when we look deeper into the role of leavened bread and the chagim.

If bread is bad and represents an inflated ego, why does the Torah require two loaves of leavened bread to be offered in the Bais Hamikdash on Shavuos – only 50 days after Pesach? Because Shavuos commemorates the giving of the Torah, which corresponds to the fourth phrase of redemption, “I will take you to Me as a People.” On Shavuos, the bread is synonymous with self-refinement to the point that even the ego itself has been refined and is now used for holiness.

This Pesach, may we experience our own personal redemption from any and all parts of ourselves, especially from those negative emotions which hold us back from achieving our full potential. May our personal redemption lead to the full and final collective redemption of our people with the coming of Moshiach very soon.