White Castle, the 90-year-old hamburger chain known for its square "slider" burgers, is sipping on the idea of offering alcoholic beverages as it tests beer and wine sales at a restaurant in Indiana.

The food famously craved by stoners in the 2004 movie "Harold & Kumar Go to White Castle" can be had with a glass of wine or a domestic or seasonal beer at a Lafayette, Ind., restaurant that fuses a conventional White Castle with a new concept for the company called Blaze Modern BBQ. Wine costs $4.50 and beers start at $3.

"This was something that customers had been suggesting," said Jamie Richardson, a spokesman for Columbus-based White Castle System. "They thought that beer and wine might go nicely with the barbecue that was available at Blaze. We're certain that we might have some customers who might enjoy some sliders and a beer or wine as well."

Earlier this year, Burger King opened the Whopper Bar South Beach, a restaurant in Miami Beach offering beer, and Starbucks has been testing beer and wine at a few sites.

The companies see alcoholic beverages as a growth opportunity after years of flat sales, said David Henkes, a vice president with the Chicago-based food research firm Technomic. "Alcohol is one of those things that is extremely profitable," he said.  White Castle's beer and wine tryout is part of a broader experiment with three concepts the company has been studying for a little over a year, Richardson said.

Besides Blaze Modern BBQ, there's an Asian food brand, Laughing Noodle, at a White Castle in Springfield, Ohio, and a triple-decker sandwich concept, Deckers, in Lebanon, Tenn.

Customers have had a "very positive" reaction to alcoholic beverages being offered in Indiana, but for now, White Castle is considering only whether to expand them to the two other co-branded restaurants, Richardson said. White Castle would face challenges trying to roll out beer and wine on a wider scale, Henkes said.

"What we find with fast-food places is, there's very strict regulations around training. Typically, a lot of the employees in fast food are under 21, so you get into some service issues," he said. "You get into some inventory issues. You get into whether distributors are willing to deliver to you because you're generally not doing a whole lot of volume in these categories."

Adding beer and wine to the menu sounds fine to lifelong White Castle fan Jim Kreml of Elk River, Minn. — even though he's a teetotaler.

"I know my wife would love that because she is a wine drinker," said Kreml, operator of a chimney-cleaning business who acknowledged he eats at the restaurants "a couple of times a week." Kreml, named in 2009 to White Castle's Cravers Hall of Fame, said Wednesday that he would expect alcoholic beverage options to be popular with many slider aficionados.

"If they're of age and they drink that already, I think they'd be happy with that. As long as they're responsible and don't sit in there, and that's not party time," he said.