What’s the difference between bread and matzah?
Blame my idolatrous love of sushi for driving me to look at the physics of matzah.
This year, I thought we would fulfill the theme of liberation by “going Sephardi”: giving ourselves permission to eat rice on Passover. Since Talmudic time, all Jews who follow strict practices have agreed to avoid the five grains that expand when cooked – oats, barley, spelt, wheat and rye. But a schism arose in the last five centuries between the Ashkenazi, Jews of Europe and the Sephardi, Jews descended from exiles from the Spanish Inquisition (and then most Arab countries in Northern Africa and the East). Maybe because they lived where the weather made them grumpier, Ashkenazi Jews interpreted the anti-inflation rule strictly and also forbad lentils, beans, corn, and rice. I voted for the warmer, gentler Sephardi interpretation largely because I had a fantasy about kosher for Passover sushi.
I lost. But to defend my unpopular position, I was driven to science to try to find out what exactly causes the dread “inflation” of matzah to make it bread. What I discovered didn’t help me win my case, but it opened up an incredible vista about the difference between bread and matzah incarnated in the biophysics of yeast. In that difference lies a Passover message about the role of the divine.
The first question by the youngest child at the seder is, “Why on other nights do we eat bread or matzah but on this night only matzah?” The answer discusses the history and symbolism of the matzah. But it begs a question. Since matzah and bread are essentially wheat flour and water, what makes bread bread and matzah matzah? The answer of course is to make bread, you need yeast. But what does yeast do?
Humans recognized and harnessed the magical properties of yeast even before they could write. Yeast makes flour and water into bread. It also makes grapes into wine. It seems to add life to inert foodstuffs, transforming them magically into something else alive. Grape juice is just a soft drink. But wine is literally a spirit. A cracker is a good delivery platform for dip, but bread is the staff of life itself. By ingesting wine and bread, we take some of that magic into us. Wine leavens our spirit. Bread sates. It’s no wonder bread and wine were worshiped by the ancients and are central to many religious rituals.
Matzah, however, is bread that is dead. Dead bread.
Though the technology of yeast has been perfected, the science of yeast still holds mysteries and surprises. To put it another way, we know the mechanics of how yeast work down to the molecular level, but how does it perform its magic?
The quantum biology of yeast and enzymes
Yeast is a single-celled living creature. When we let these critters feed on their favorite food, sugar or anything that contains sugar or carbohydrates, they digest it into sugar’s components: energy, alcohol, carbon dioxide, and some residue molecules that add flavors. The process the ancients observed was bubbling, rising fermentation. When we bake bread, the heat evaporates alcohol. Carbon dioxide gas bubbles expand and burst contained by the sticky dough. This gives bread its texture. In the cooler processing of wine (and beer), the alcohol is completely contained in the liquid for our pleasure. Carbon dioxide is partly released when wine is moved in barrels. Some is left at the discretion of the winemaker. More often the wine is “degassed.”
In high school chemistry, they may have used yeast as an example of enzymatic activity. But what they didn’t teach us, because chemistry isn’t etymology, is that “enzyme” is just the Greek for “in yeast.” The ancients saw, and even worshiped, the way yeast brought bread and wine to life. Now, modern biology is coming to grips with this ancient wisdom: yeast, or enzymes, are the gateway between the living and the inert, literally life and death. The new science of quantum biology has started to answer the question of how yeast performs this magic.
Yeast is the ur-type of all enzymes. Enzymes are present in all living things, in every living cell on Earth, and in every process that sustains life: digestion, neural action, making new cells and repairing old ones (growth and healing), reproduction, and so on. So enzymes inhabit the borderland between living and non-living things. They’re not organisms, but no organism or living process survives without them. In short, they’re a good battleground for the eternal philosophical war between materialists and vitalists. Materialists believe the universe and everything in it, including humans and human consciousness, is a vast machine. It is made up only of physical things and the physical processes or forces between them. Vitalists argue that there is a meta-physical force in the universe that animates all life, a force that cannot be reduced to mechanical explanations. Human consciousness particularly illustrates the problem and limitation of materialism. Fundamentalist materialists argue that everything can be explained ultimately, by self-consistent systems of reason, like logic or mathematics. Religious vitalists argue that the metaphysical force is divine.
Although yeast is a living thing, enzymes have until recently seemed to be purely chemical machines, although how they added life so efficiently was still mysterious. In the debate between materialists and vitalists, enzymes have been the best proof for the materialist view of life. They seem to explain how life is introduced into inert matter without resort to non-mechanistic explanations. Until now.
It turns out that enzymes require quantum effects to do their work, and quantum mechanics may defy a strictly materialist view of the cosmos. At its best, how quantum physics operates defies logic, though we’ve learned to use them in MRIs and computer chips. At its worst, every quantum process requires an aware being, an observer to watch it work in order for it to be real.
Five weird things about quantum mechanics
I know to most of you unfamiliar with it this claim for quantum mechanics seems just weird. There’s no way to explain any quantum process without over-simplifying or resorting to analogies which dangerously distort its actual, full-on weirdness. Many have tried and some have succeeded. Let’s just say the quantum is profoundly counter-intuitive. But here are a few of the weird facts that you will need to know as we continue with our discussion of matzah. I leave it to you to discover whether you buy any of it yourself:
- Sub-atomic entities behave like both waves of energy and particles at the same time.
- A sub-atomic entity isn’t in any one specific place until you observe it. Then it seems to settle on one. (Uncertainty)
- A single sub-atomic particle can be in two places at once. But if you affect one, its other self will react, even if they are separated by millions of miles. (Superposition)
- They can pass through otherwise impassible-seeming barriers (quantum tunneling) and “travel” faster than the speed of light.
- When a subatomic particle is observed or measured, it “collapses” from its various possible quantum states into one state. I.e,. it stops behaving quantumly and starts behaving classically. (Measurement)
Quantum tunneling in yeast
To understand the quantum theology of matzah, the last aspect is the most important. Until now, biologists have been fairly content to leave the weirdness of the quantum world among physicists. They assumed there was an unbreachable barrier between the sub-atomic world of quantum weirdness and the macroscopic world of biology obedient to classical laws of physics. Thankfully (they believed) subatomic monkey business collapsed when it poked its head up into an organism because the complexity of the organism automatically “measured” (observed) it (though no one specified how). They now seem to be really wrong. It’s awkward.
Resurrected by water, living yeast seems to make the inert come alive. Yeast works enzymatically to ferment the sugars in flour. It explodes the flat mound of dough and makes it rise as little bubbles of alcohol explode inside. It adds tastes by creating new molecules. But what was once thought to be a classical, if incompletely understood, mechanical process (catalysis) we now know requires quantum tunneling.
Here’s the technical explanation: an enzyme in yeast takes a positively charged sub-atomic particle, the proton from the alcohol it has created, and transfers it to another molecule. This new molecule, with the addition of its extra proton, now has a positive charge. Like a magnet, it now attracts molecules carrying a negatively charged particle, the electron. So the new molecule the yeast created (called nicotinamide alcohol dehydrase or NADH) becomes a very effective carrier and releasor of electrons. With NADH, the ingredients can now perform their actions very quickly and efficiently. It’s like the brew now has an electric current running through it, with electrons able to hitch a ride and jump off when a chemical reaction needs an extra jolt of energy to make it happen.
So far so good. This is all safe, mechanical chemistry.
As it turns out, though, the speed at which electrons get transferred from alcohol to NAD+ to make NADH cannot be explained by classical chemistry. Quantum tunneling, number three on our list of weird quantum effects above, can. Again, at the risk of over-simplifying, a subatomic particle like an electron can travel across barriers instantaneously by using its superpower of quantum tunneling. As this effect occurs among millions of molecules in the dough, it speeds up the process enough for biologists to conclude it must be involved.
This neat explanation of the quantum role in enzymatic action leaves one huge mystery, though: In order for the transport of the electron to occur, it can’t be just a probability, and in order for it to be more than a probability, it has to be observed or measured. The quantum behavior – the electron can be here or there and therefore nowhere at all, really – has to become classical behavior. I see it now. Until now, biologists, scientists and other materialists have maintained that the macroscopic bulk of the organism in which the quantum action occurs collapses any quantum craziness, that the fact of the organism as a macroscopic entity itself performs the “observing.” But that argument no longer holds water and even seems like a tautology, fabulous circular reasoning, because enzymes involve quantum action. Enzymes, and the quantum, is ubiquitous in every process of every cell in an organism. In fact, it seems to be the essence of life itself.
“Enzymes have made and unmade every living cell that lives or has ever lived. Enzymes are as close as anything to the vital factors of life. …. [T]he discovery that enzymes work by promoting the dematerialization of particles from one point in space and their instantaneous materialization in another provides us with a novel insight into the mystery of life.”
– Johnjoe McFadden, Jim Al-Khalili, Life on the Edge: The Coming of Age of Quantum Biology (Broadway Books, Jul 26, 2016) p. 97
There’s simply too much quantum funny business going on everywhere in a living being to say one part of the organism is classical and collapses the other part that’s quantum.
Another way materialists banish the quantum: the Many Worlds Hypothesis
Scientists have resolved the measurement problem another way. When the wave of quantum possibilities collapses into an actuality, the information contained in those probabilities has to go somewhere. Indormation, like energy, as its own law of conservation in the universe. Quantum physicists hypothesize that instead of collapsing the quantum into the classical through observation, every time a quantum event collapses into a classical one, other universes are spawned. All the other probabilities that didn’t occur here do occur there, in these new universes.
This hypothesis is mathematically satisfying and sidesteps any suggestion of metaphysics. But there are a virtually infinite set of quantum events occurring everywhere at every instant everywhere in an organism, let alone the whole universe. Each of them would create an incalculable set of alternate universes. You do the dizzying math. Or alternatively, ask yourself: Which is the more ridiculous vision of the cosmos? This vision creates an even crazier and more incomprehensible cosmos than the one we have.
But who knows? That’s what they said about quantum theory in the twentieth century. And that’s what most well-educated, modern, rational sophisticated people say about God.
Quantum theology of matzah: Where is He?
Quantum theology is a term used by a few but growing number of theologians and mystics. They are eager to seize on quantum theory to prove the existence of God. Many of their essays and speculations are plagued by vagueness, weak understanding of science, and an over-heated, optimistic leap into the irrational analogies between quantum science and the mystical. Their “proofs” often require taking analogous-sounding mysteries as literal equivalents. Quantum theology is largely the provenance of well-educated fundamentalists.
The case of yeast is different. In this dance between the material and the vital, between science and faith, the science leads us to conclude something mystical is happening in bread that doesn’t occur in matzah. The new science of quantum biology shows quite specifically how the process of life itself depends on quantum action. In every possible process where life is created or sustained, enzymatic action is involved. And with quantum action comes the requirement that someone or something is observing the process. The nose of the quantum camel, and the problem of a conscious observer, has entered the tent of biology, but they were summoned by the biology. In fact, the tent is the camel. Something or someone has to be observing omnipresent quantum events in enzymes to make them operative in life. Someone or something has to be operating life. Omnisciently.
Couple biophysics with the metaphysics of the matzah and we get a powerful sermon. Matzah is bread without attention, perhaps without the attention of a Cosmic Consciousness. It represents enslavement to inert material. It is both literally the bread of affliction, the food of slaves, and symbolically life without redemption from our inner Egypt, the body without a soul. Matzah invokes a God who redeemed the Children of Israel from slavery more than three thousand years ago (3330 to be exact) and Who continues to operate the universe today by attending to its every quantum event. He is an incomprehensibly vast God Who observes every infinitesimal event, all the infinite infinitesimal events that occur every instant to sustain each living cell of each living organism. This is a God that watches everything actively. This God expands and unfolds His Cognizance as much as the universe imagined by the Many Worlds Hypothesis multiplies infinitely bubbling alternatives, only this God gives it life and an elegant unity. I like this God and this idea of Him.
One of the sermons on matzah is a kabbalistic one. Isaac Luria, the 16th century mystic of Safed, explains that the three matzahs on the seder plate represent Knowledge, Understanding, and Wisdom. Matzah invites us to stretch our scientific wisdom to its fullest extent beyond enslavement to our preconceptions. It suggests the liberation of science from its prejudices. Is it really harder to believe in God than in the Multiverse Hypothesis? I don’t think so. The benefits of embracing both the intrinsic beauty of the metaphysical explanation and the elegance of its logic make a pretty persuasive case against atheism. From the outside looking in, all the attempts to bracket out a Universal Observer from the quantum situation look like contortions by science to avoid the obvious, the result of a fundamentalist-like commitment to a belief that there must not be a God in the universe.
This message in the matzah makes it the twin of Elijah’s cup, its secret sharer and, perhaps, the answer to the question it poses. When my children saw Elijah’s cup was always empty at the end of the seder, they asked, “Where is he? When will he come?” The matzah asks the same question about God: “Where is He?” and answers, “Not in this poor, dead bread that we eat because we are slaves. But in everything that lives.”
 Prof. Judith Klinman of UC Berkeley first suggested that quantum processes were involved in the enzymatic action in 1987. She has more recently found experimental evidence for it. See, for instance, Judith P. Klinman and Amnon Kohen, “Hydrogen Tunneling Links Protein Dynamics to Enzyme Catalysis,” Annual Rev Biochem. 2013; 82: 471-496.