Dr. Jon Greenberg likes his Chanukah menorah as much as anyone.

He can tell you why the olive, and its burning oil, makes a perfect unifying symbol for the Jewish people after the victory of the Maccabees.

But as a scientist and scholar who uses the tools of botany and ethnobotany to understand Judaism, a hint of wistfulness seems to enter his voice when he describes a Chanukah practice described in the Book of Maccabees, a practice that never caught on but did use five kinds of plants.

The Book of Maccabees isn’t part of the Tanach, the Jewish Bible. But it was preserved by Christians, who kept it in their scripture. It doesn’t tell the story of miraculous eight days of flame from one day’s worth of oil. (That’s from the Talmud, which was later.) Instead, it explains that because the Maccabees who were fighting against the Greeks were hiding out in caves and mountains, they were unable to celebrate Sukkot. After they captured and reconsecrated the Temple in Jerusalem, “they wanted to make up for the Sukkot they missed,” Dr. Greenberg said. “It was meant to be a do-over.”

That eight-day celebration — re-enacting the seven days of Sukkot and the eighth day of Shmini Atzeret — was repeated in subsequent years and became Chanukah. In that first year, the Maccabees took the four plant species of the Sukkot holiday — the lulav, the willow, the myrtle, and the etrog — and wrapped them in a fifth species, an ivy, “probably because it was the symbol of victory in Greek culture.

“Apparently it didn’t catch on,” Dr. Greenberg said.

As to why the olive reflects unity in Jewish culture — first a word about the topic of his program, set for 8:30 p.m. on Saturday night at Teaneck’s Congregation Rinat Yisrael: “The Culture War That Shaped Jewish History.” The Rinat Yisrael talk is only for those 21 or older. Reservations are required for the evening, which costs $15, but there is “limited drop-in availability on a first-come, first-serve basis” according to one of the event’s organizers.

The culture war that Dr. Greenberg will speak about is between wine and beer. It goes back to the origins of beer.

“There’s a lot of evidence now that beer-making preceded agriculture,” Dr. Greenberg said. “It may have been one of the driving forces of civilization, of settling into towns.”

The theory goes like this. Before people grew crops on their own, they collected wild seeds to eat. They would cook some of them, and they would make a soup out of the leftovers. It was “a gruel made of wild grasses,” Dr. Greenberg said.

People discovered that if the gruel was thick, like a porridge, they could put it back in the fire and get bread, which was a good thing

If it was thin, the soup would ferment and become beer, which, by some measures, was an even better thing.

This led people to collect and store more grain. And then eventually they realized what it meant when some of the stored grain would sprout. They could plant the sprouts and grow more grain. Voila! Agriculture, and beer to toast it with.

In the cities of Egypt and Mesopotamia, Dr. Greenberg said, the fermented beer became a point of cultural pride and a part of their religion. “In Egypt, there was a goddess associated with beer,” he said.

The beer was weak. Sometimes it was stained red with pomegranate juice for ritual use. But it was not portable. Nomads couldn’t take beer with them on their travels, because their jugs and jars would kill the carbonation. The fizz would be gone.

Instead, nomads rejoiced when wine was discovered. Wine also provided alcohol and nutrients, and it could be carried from place to place. “Archaeologists have found little figurines of camels carrying amphorae of wine,” Dr. Greenberg said.

In time, the different beverages symbolized the differences between the settled and nomadic cultures, and became associated with differences in religion, he said. “Jews to this day prefer wine to beer for kiddush or havdalah,” he said.

Which brings Dr. Greenberg to the Joseph story, and this week’s Torah portion.

“There’s some evidence that Egypt was conquered by the Hyksos, who came from the north shortly before Joseph arrived,” he said. “The Hyksos had connections to the Greeks. They were wine drinkers.”

Would the new rulers respect the local culture and become beer drinkers? Or would wine become the new elite beverage for Egypt?

“While this debate was going on, apparently quite a few Egyptians were kept in the civil service,” Dr. Greenberg said. “The first thing the Torah tells us about Potiphar is that he was ish mitzri, an Egyptian man. In other words, an Egyptian in a Hyksos occupation government.”

In Dr. Greenberg’s telling, the wine steward and the baker whose dreams Joseph interpreted in prison were victims of the ruler’s impatience with the culture wars. The wine steward — also translated as butler — represented wine. And the baker, in this telling, stood in for beer, which at this stage in the evolution of brewing technology was formed not from porridge but from soaked bread.

“Each had a dream. Joseph sort of wanders into the middle of this. Eventually you have this wine-drinking culture getting close to Pharaoh, and the wine steward is restored and the baker killed,” he said.

Later on, he said, the rules of Passover can be seen as rejecting Egyptian culture. Egypt baked fancy bread and brewed from leaven; bread and leaven were banned on Passover. Egyptians worshipped a ram god; Passover called for a lamb to be roasted.

“It had to be cooked directly over the fire, the most primitive method,” he said. “As if we were saying to Egypt, ‘We don’t care that you have the most sophisticated methods of cuisine, we’re going back to primitive means of making bread and cooking meat.’”

With this understanding of how food can separate cultures from each other, we can return to the unifying aspect of the olive on Jewish culture.

“For its size, Israel is the most ecologically diverse country in the world,” Dr. Greenberg said. “It has deserts, forests, mountains, until the 1930s it had swamps with crocodiles. But if you grow olive trees in Israel, your olive trees will flower within two weeks of everyone else’s. Your olives will be ready to harvest within two weeks of everyone else’s throughout the country.”

Thus, the olive tree became a symbol of national unity.

After the Maccabean revolt, which was in large measure a civil war, “there was a need for the reunification of the Jewish people,” he said. “There was a winner and a loser and they had to reconcile somehow. The olive oil appealed to people in a way that the ivy-wrapped four species didn’t.”