Wine figures prominently in the Jewish Passover, which begins April 15 this year, and Christian Easter, two days later. The Last Supper was a Passover celebration, in which Jesus told his disciples the wine they were drinking was his blood, given in sacrifice for them. Drinking wine brings redemption. Today’s Eucharist or Communion re-creates this moment and its powerful symbolism, whether with wine or grape juice. In the modern Passover Seder, adult celebrants consume four cups of wine (“cup” not being a precise measure) to commemorate the redemption of the Israelites from slavery under the Egyptians. A fifth cup is poured but left unconsumed in hopes the prophet Elijah will pop by with news of the Messiah – hope for future redemption.

Each year in the weeks before Passover, I’ve recommended several kosher wines, and I’ve written before about the significance of wine in the Passover ritual. But some misperceptions and questions persist about kosher wines.

– What makes a wine kosher?

On a basic level, a kosher wine must be made according to Jewish dietary laws and under supervision of a rabbi. Any added ingredients – such as yeast or fining agents, if used – must be certified kosher.

Covenant winery founder Jeff Morgan, right, and winemaker Jonathan Hajdu. Courtesy of Covenant Wines

“Kosher wine can be made exactly like non-kosher wine,” says Jeff Morgan, a wine writer, cookbook author and founder of Covenant Winery in Berkeley, Calif. “The only real difference is that a kosher wine must be handled by sabbath-observant Jews from when the grapes arrive in the winery until bottling.” And, well, maybe beyond bottling (see below).

Morgan makes 24 kosher wines, 19 in California and five in Israel. His point is that kosher does not signal quality – or lack thereof. “Most of our wines at Covenant are native-yeast fermented, unfined, unfiltered and dry,” he says. I’ve tasted a few Covenant wines and will attest to their quality.

Since wine is made with one basic ingredient, the kosher determination is simple compared to processed foods made from many ingredients on various types of equipment, all of which must be kosher.

– Are kosher wines boiled?

No. The myth of boiling is one of two misconceptions leading to kosher wines’ reputation of poor quality. There is a subcategory of kosher called mevushal, which requires a product to be heated to 185 degrees, but that’s well below boiling, and it doesn’t have to stay there for long. The advantage of mevushal is that the wine remains kosher even if served by nonobservant people. Kosher mevushal wines are therefore in high demand for restaurants and catered events.

Any wine lover knows heat is the enemy of wine. Cellars are cool for a reason, and we reject wines that taste “cooked.” But kosher wines can be made mevushal using modern techniques such as flash pasteurization. Many use a technique developed in the early 1990s called flash detente, in which uncrushed grapes are rapidly heated and then pumped into a vacuum chamber. The grapes then explode, extracting color and fruit flavor from the skins in an instant that might take a more conscientious winemaker weeks to achieve through cold maceration.

Flash detente is widely used to “correct” wines for underripe green flavors, mold, even smoke taint from wildfires by separating these faulty elements from the wine. That doesn’t mean mevushal wines are necessarily inferior in quality and need to be corrected. Wineries may “flash” their wines to attain the mevushal certification so they can be sold to restaurants and caterers.

– Aren’t kosher wines all sweet?

This is the second myth contributing to the misconception that kosher wines are poor quality. Orthodox Jews who immigrated to the United States – especially to New York City – following World War II needed kosher wine for their Shabbat meals and for Passover. Several companies turned to New York vineyards and the Concord grape, which makes a very tannic, acidic wine that needs to be sweetened to be palatable. But that does not mean all kosher wines today are sweet. Most are made with European vinifera varieties just like non-kosher wines, but by observant Jews.

– What do the kosher certifications mean?

The most common certification in the United States is the Orthodox Union, which shows a “U” inside a circle. A “P” on the side means kosher for Passover, indicating the wine was made without certain additives frowned upon for the holiday. You may see several other emblems on wine labels attesting to the blessing of this or that rabbi bestowing kosher status on the wine. Let’s just say that various Jewish communities have their own loyalties. Any winery will seek various certifications to appeal to a wider market. And of course, there’s “kosher mevushal.”

– Is kosher wine just for Passover?

“Is champagne just for New Year’s Eve?” Morgan asks. There’s the weekly sabbath meal, of course, and other Jewish holidays. Observant Jews may prefer to stick with kosher wines year round, and there are an increasing number of good ones to choose from. Given some of the kosher wines I’ve tasted lately, I’m happy to join in a toast.