Duke's Mayonnaise is breaking out of the Southeast, now the No. 2 mayonnaise brand in the nation. From viral moments — like almost knocking out Coach Shane Beamer and being Benny Blanco's choice for Selena Gomez's late-night grilled cheese — Greenville's beloved mayo is making it big.

I got a behind-the-scenes tour of the factory in Mauldin. I thought I knew all there was to know about Duke's, but I learned a lot — and I'm excited to share it with you.

Why Duke's is the best

"Our competitors have changed their mayonnaise recipe in the past hundred years," said plant manager Daniel Moore. "We have not."

The recipe hasn't changed since 1917. Unlike its competitors, Duke's only uses egg yolk, which gives it that signature yellow tint and makes it thick and creamy in texture.

"We use about 70,000 lbs of egg yolks per day," Moore tells us. "There's about 10.5 egg yolks per pound, just in our mayonnaise process."

Plus, it's got Twang (duh). That unique flavor comes from cider vinegar.

It's made right here

Some rumors are circulating that Duke's is no longer made here, and while the brand's parent company was acquired earlier this year, production has remained unchanged.

"There is no manufacturing facility that can absorb what we do at this time," Moore reassured me. "We're very proud of our recipe. We're very proud to be right here in Mauldin, SC, and from right here in Greenville, SC."

The facility on Main Street in Mauldin produces 1.1 million pounds of condiments per day, It's primarily mayo, but they also make salad dressings, barbecue sauce, ketchup, mustard, relish, and more. In addition to Duke's, they also produce some private-label condiments.

"The acreage of land that it takes to produce that soybean oil we use in a year is slightly larger than the state of Rhode Island," Moore said, to put the volume into perspective. "We do support a lot of farmers."

The production process also supports farmers by utilizing the "sludge" — an oily, cakey waste byproduct — as fertilizer.

There's also a quality lab on site that tests for acidity content, salt content, and viscosity to ensure they deliver the same product to consumers every single time.

The history

1917 | Eugenia Duke began selling her sandwiches to soldiers at Camp Sevier, charging $0.10 per sandwich and making a $0.02 profit. "If you think about women here in 1917, they were either a textile worker or a teacher," said local historian John Nolan. "To start a business on her own like that, it's pretty amazing." When she sold her 11,000th sandwich, she bought her first delivery truck.

1920 | In a few years, she was selling her sandwiches at drug stores and local grocers, and at Duke Tea Room around the corner from the Ottaray Hotel at 112 West North St.

The Ottaray was known for its good food, including Eugenia's iconic sandwiches. | Photo via Greenville County Library System, South Carolina Room Archives

1921 | She was there for less than a year, and she broke a three-year lease to open inside the Ottaray.

1923 | She sold her sandwich business to focus on the production of mayo, which was what she realized made her sandwiches so popular. Fun fact: At this time, her sales force was Aall women. "She was a pioneer in that sense," said plant manager Daniel Moore.

1926 | Mayo production moved to what is now the Wyche Pavilion along the Reedy River, currently under construction as part of the Peace Center's renovations.

1929 | The CF Sauer Company — based out of Richmond, VA (hey, RICtoday) — bought Duke's.

1950 | Eugenia moved to California to be closer to her daughter and went back to her roots, creating "The Duchess Sandwich Company" and selling her sandwiches to cafes and drugstores.

1954 | The current facility where Duke's Mayo is manufactured was built, and they moved operations from the river one year later in 1955. It was expanded in 1990.