The plot thickened plenty, even if the chili never did.

Cincinnati, Ohio’s chili industry, which traces its roots to a Prohibition-era discovery by immigrant brothers Tom and John Kiradjieff, has grown into a $159 million economic engine.

That’s the conclusion of a new “Chilinomics” study conducted by Gold Star Chili.

“No other area restaurant concept has this kind of positive impact,” said Gold Star CEO Mike Rohrkemper, who offers the following data to support his claim:

• More than 200 Cincinnati-area chili parlors employ 2,700 people. Their $48 million annual payroll works out to about $18,000 per employee.
• Tri-State chili companies spend about $45 million each year on ingredients, most of it supplied by local food vendors. They spend another $38 million with suppliers of insurance, maintenance services, and other operating expenses.
• The chili industry typically turns out 10 new stores a year, which cost a combined $12 million to build and equip.
• Finally, cravings for that spicy stew that Cincinnatians call chili but outsiders call soup over noodles supports annual grocery spending of $16 million.

Gold Star’s financial executives started crunching numbers last year to support a new marketing campaign. Gold Star is trying to collect 50,000 signatures on a petition asking local governments to designate Cincinnati as Chili Town USA.

The marketing campaign comes at a tough time for the nation’s restaurants, which endured two straight years of declining sales and are projected to see flat revenue in 2010, according to an industry forecast released in January by the National Restaurant Association.

Rohrkemper said Gold Star’s revenue remained at $65 million last year.

Skyline Chili CEO Kevin McDonnell wouldn’t provide sales data but said his company is focusing on product quality and customer service during the downturn.

“We’re hanging in there,” he said.

The Kiradjieff brothers could not have foreseen the impact of their culinary concoction, but their descendants are no less proud of what their Macedonian ancestors wrought.

“Sure, we’re the first,” said Joe Kiradjieff, whose father, Tom, was co-founder of Empress Chili. “We still think we’re the best.”

Joe Kiradjieff is semi-retired, now that he’s 80. The Bridgetown, Ohio, resident sold Empress in 2009 to Jim Papakirk, a Blue Ash attorney whose father-in-law, John Johnson, owns Camp Washington Chili. Joe Kiradjieff still helps Empress with franchise startups. And he still guards with vigilance that “secret formula.” Is it chocolate? Cinnamon? Or is it cumin and cloves that unlock the taste buds, turning its consumers into Cincinnati devotees?

“Your biggest kicker is your spice formula,” but the real magic lies in how all of the ingredients come together, Joe Kiradjieff explained. “Tomato puree, for example. If you’ve got too much of that, you’ve got too much tomato flavor.”