Leavening

As I was browsing a number of articles about wild yeast, I read several that mentioned the early evidence of deliberate fermentation, including some kind of Chinese alcoholic drink from 7,000 B.C. and leavened Egyptian bread from 1,000 B.C. Considering that the Jews appear to have shown up on the eastern shores of the Mediterranean shortly after the catastrophic collapse of Bronze Age civilizations around 1,200 B.C., and considering also the Jews' complicated relationship with Egyptian culture during the next millennium, this reminded me of something that surprised me in the Biblical exegeses I've been working on in recent years at Project Gutenberg.

In both the Old and New Testaments, "leavening" has a strangely negative connotation of impurity and corruption. I'd always assumed that the point of unleavened Passover bread was that the homemakers were in a rush, but there's more to it than that. Part of the Passover ritual is a strenuous disinfection of the home from all leavening, not just so that the bread will be truly unleavened and therefore qualify for the ritual, but also apparently as a symbol of purification. Exodus 12:15, 13:6-7. Leviticus 2:11 forbids the burning of yeast on the altar at any time, not just during Passover. Both Jesus and St. Paul used leavening as a metaphor for spiritual or psychological infection that can start with a small fault and bloom until it consumes the person: hypocrisy in Matthew 6:6-12 and Luke 12:1, and sexual immorality in 1 Corinthians 5:1-8.

For some reason this opprobrious attitude didn't extent to alcoholic fermentation, which the Jews apparently didn't connect closely with bread fermentation. The Jews never have thought much of drunkenness, but they don't react to alcohol with horror at impurity in the manner of temperance zealots. I have cousins who, in my youth, startled me by casually explaining that they wouldn't eat things like olives because they were produced by a variety of fermentation. The fermenting bacteria break down the bitter flavor in raw olives, without producing any mind-altering substances, but apparently even the presense of the word "ferment" was enough to make my cousins swear the whole thing off. They didn't object to leavened bread, however.