Fifty years ago, when the Second Vatican Council issued the Nostra Aetate ( In Our Time ) document that condemned the Roman Catholic Church’s history of anti-Semitism and aimed to open up relations with Jews, church leaders probably weren’t thinking about interfaith beer brewing.

But things have changed since then. The craft beer industry has exploded. Pope Francis is considered a strong defender of the Jewish people. 

And Jeremy Cowan of Shmaltz Brewing and Brian Neville of Cathedral Square Brewery started the Immaculate Collaboration. 

The two brewers — the former is a Jew from New York, the latter a Catholic in St. Louis — met almost 15 years ago in California and remained in touch as they each moved around the country.

For the past five years, they have brewed beers that mix recipes, ingredients and equipment from the two companies.

They are brewers with a passion for their beverages who don’t shy away from tossing in religious references with the hops. 

Cowan, 47, started Shmaltz Brewing, which makes kosher beer under the He’Brew label, in 1996. The company has grown from contracting with larger brewers to produce its beers to opening a production facility in Clifton Park, N.Y. 

The founder will print labels with quotes from Mel Brooks movies alongside words from the Old Testament. 

“It’s a Jewish celebration beer,” said Cowan, who stopped at Llewellyn’s in Webster Groves during a visit to St. Louis earlier this month to meet with a new distributor and promote his beers such as the SHE’BREW Double I.P.A. and Slingshot American Craft Lager. (Think David and Goliath.) 

The brewery sells to about 15 bars around St. Louis. In terms of attracting a Jewish audience, Cowan said, it’s not all about the kosher label. As he admits, most Jews who keep kosher do not look for a label on beer, which generally does not require certification.

“If people want to be more involved in the religious side of the (Jewish) community, I think we have the beer that’s available for them,” Cowan sadi. “And if people just think that ‘Blazing Saddles’ is hilarious, I think they will really like our branding as well. But the bottom line is we make very high-quality craft beer with a unique angle.”

Cowan and Neville have produced beer together with names such as St. Lenny’s I.P.A. and the recently released Immaculate Collaboration V, a beer that melds Cowan’s pomegranate strong ale recipe with Neville’s saison yeast before it’s aged in Neville’s “Ave Maria barrels for a year,” Cowan said. (Ave Maria is the name of a Cathedral Square Double Abbey, described as containing a “hint of sin that will have you asking for the intercession of the Virgin Mary!”)

“Very, very special barrel-aged beer, (we) have a lot of fun with that project,” Cowan said of their collaborative beers. 

Cowan was raised a Reform Jew in northern California. He said his relationship with Judaism changed when he was in his early 20s and took a vacation to Israel. He ended up doing a five-month program in a Modern Orthodox community in Tzfat. 

Before that “it had been knowing that you’re part of something without necessarily doing anything about it.” 

Afterward, he started participating more in the Jewish community and now will hold events tied to Jewish groups and holidays. For example, the brewery hosted a Jewish cultural festival July 13 with a Chabad house in New York.  

During Sukkot last year, the brewery held a beer tasting at Congregation B’nai Amoona’s Scotch in the Sukkah event. 

“Each and every person found something they liked, and I told them where they could find it in a grocery store,” said Jeff Doerr, who works as the Midwest regional sales manager and is not Jewish. “They also educated me quite a bit about the actual ceremonies.”

Neville, the Cathedral Square brewmaster, produces Belgian-style beers in the style of the Trappist monks. He said he and Cowan hatched the idea for a joint project while drinking beer at a bar in New York. After Neville suggested calling it the Immaculate Collaboration, they then had to figure out how to actually collaborate. 

“I said, ‘Well, let’s make it easy, let’s brew one of your beers with one of my Belgian yeasts,” Neville said. 

They would use the Lenny’s I.P.A. recipe and call it St. Lenny’s. Both said that no one has ever given accused them of being sacrilegious with their beer brewing. 

The Cathedral Square owners have purchased a church in the Central West End and are in the process of converting it into a restaurant and brewery, Neville said. 

He said he enjoys working with Cowan, whom he described as a fellow pioneer in the craft brewing industry.

The goal, he said, is “keeping the dream alive and making good beer and selling good beer, and (a) good friendship.”

The Jew also said he enjoyed working with the Catholic. They hit it off when they first met, he said, and have now been “friends for over a decade.”