The idea came from a co-owner of the grocery stores that sponsor the event. Tim Metcalfe said he was inspired last year after he attended Lifest, a large Christian music festival in Oshkosh, the Wisconsin State Journal reported.
"I think God was always in my heart, but I didn't have a relationship with my faith," he said. "I wasn't attending church. This changed everything for me. It was my moment. Afterward, I drove home and said, 'What do I do with this?'"
Brat Fest, which bills itself the world's largest such event, spans four days from Friday through Memorial Day.
Metcalfe said Christian music has a huge following so it'll be there for people who want it, while those who aren't fans will have alternatives such as rock.
But could the move alienate those who'd prefer the event remain secular? Possibly, said Mike Judge, who directs the Center for Brand and Product Management at the University of Wisconsin-Madison's business school.
He said people in some parts of the country, such as his hometown of Oklahoma City, appreciate when businesses acknowledge Christian principles. But Madison residents seem more wary of public displays of religion, he added.
"My gut tells me there might be a little bit of a social media flare-up over this," Judge said. "But as long as religion doesn't become an overwhelming presence at Brat Fest, I don't think it will be a negative for the brand. And it could be good for business if it brings in a different segment of consumer."
Brat Fest donates proceeds to the nonprofit organizations whose members volunteer to staff the booths. Now in its 32nd year, the event has raised more than $1.3 million for local charities.