How S.Rosen’s Became The King Of Chicago-Style Hot Dog Buns

HERMOSA — If you’ve ever ordered a hot dog in Chicago, it likely came nestled in a bun from S.Rosen’s Mary Ann.

Actually, statistically it’s far higher than “likely.” Alpha Baking, which owns the brand, estimates that 95 percent of Chicago’s hot dog stands use its buns.

Considering Chicago’s love affair with the hot dog, that’s a lot of buns. And to be sure, S.Rosen’s Mary Ann cranks out a staggering number, especially during the summer months, when the factory runs 24/7.

Currently, it’s baking more than 4 million hot dog buns a week. 

Each and every one of those buns is baked in a long and narrow building in Hermosa. Though the owners don’t know exactly when the building was built, they estimate that parts of it are at least 100 years old. 

Nearly every part of the baking process is automated. Flour is fed to the mixers through tubes that hang from the ceiling. A maze of conveyor belts winds through the space, advancing the dough as it’s shaped, proofed, baked, sliced and packaged. 

Even with all the automation, workers are there at every step, carefully monitoring the buns, said Plant Manager Raul Lopez. Lopez can look at the dough at every juncture and know if it’s ready. 

What makes S.Rosen’s buns so crucial to a Chicago-style hot dog? Director of Marketing Stephanie Powell said it’s all about balancing softness with hinge strength. 

“The Chicago-style hot dog has a lot of ingredients, and if the hinge breaks, it becomes a mess,” Powell said. “So we make sure our buns have strong hinge strength while staying soft.”

Two Baking Companies Unite 

As the name suggests, S.Rosen’s Mary Ann used to be two separate companies. The former was founded in 1909 by Sam Rosen, who specialized in Eastern European-style rye bread. The Mary Ann Baking Company began in 1935, and from the start it sold poppy seed-studded hot dog buns, which eventually became the preferred bun for the Chicago-style hot dog. 

In 1979, Alpha Baking Co. bought Mary Ann Baking; two years later, it merged with S.Rosen’s. Because Mary Ann and S.Rosen’s were beloved local companies, Alpha Baking decided to use both names for the buns, creating the brand name we know today. (Oh, and there is no space after the period. That was how it was written early on, and the company still likes the way it looks.)

The factory also produces hamburger buns, including for big-name clients. But it’s the hot dog bun that truly defines the brand. 

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The process starts with a sponge, which in the baking world refers to a mixture of flour, water, yeast and salt that is fermented for hours before being mixed with the rest of the dough. 

“The sponge reduces the mix time and gives it the right taste,” Lopez said. “It sits anywhere from four to six hours. At any time, we have around 14 sponges fermenting.” 

Once the sponge is ready, it joins the rest of the dough ingredients in an enormous industrial mixer, where it’s kneaded for 15 minutes straight. Then it’s fed through a chute into a machine that divides the dough first into small balls, and then into long tubes, approximately the length of a bun. Each one lands in a large metal baking tray, which winds its way toward the proofing room. 

Here the dough rests for 52 minutes in an enormous room held to a specific heat and humidity level. 

“Time and temperature are the most important things for baking,” Lopez said. If “you can’t get the right mix time or the right temperature, everything else is gonna be a challenge.” 

To make sure everything stays consistent, the trays are in constant motion, with machines moving them up and around the space. During this time, each piece of dough expands to fill the bun-sized slot in the hot dog trays. 

Without slowing down, the trays head to the oven. It’s at this point where the buns may or may not get their distinctive covering of poppy seeds — an average of 916 poppy seeds per bun. The addition is far more popular for buns sold locally.

“In the Chicagoland market, poppy seed buns outsell plain buns two to one, but that changes dramatically outside the area,” Powell said.

Once coated, the buns head for a 60-foot-long oven. The trays keep moving, running down to the end, before coming back. Baking time usually takes 7 and a half to 8 and a half minutes, depending on where the buns are headed. 

“Some stands like buns lighter in color, and some people like it a little bit darker,” Lopez said. “It all depends on the preference of the customer.” 

While still hot, mini suction cups suck the finished buns out of their trays and transfer them to another conveyor belt that speeds them to a room where they wind around for 15 minutes to cool down. Then they are sent to different lines depending on the package size of the final product.

Seconds before they are packaged, the buns are sliced. They’re pushed into bags, wrapped up and moved to either boxes or trays, depending on the destination. 

Buns Designed To Go The Distance

The buns are monitored throughout the process to ensure freshness and quality. Workers toss out buns that haven’t proofed correctly or that accidentally stuck to each other. A metal detector checks the buns before they are packaged and afterward to ensure no foreign matter has gotten inside. 

Many of the drivers behind the wheel of the company’s fleet of delivery trucks have been with S.Rosen’s for years.

“Not only do the drivers know the city like the back of their hands, they know their customers, too,” Lopez said. “Many stands have the same driver for many, many years. And they expect fresh buns.”  

Lopez credits the expertise of the workers for making S.Rosen’s Mary Ann Chicago’s bun of choice. 

“Many of our employees have decades of experience,” he said. “Two of our oven operators have both been here for more than 25 years.” 

This institutional knowledge and attention to detail has kept the company going and customers coming back for buns they know they can depend on. 

“There are cheaper hot dog buns, but stand owners know they fall apart,” he said. “That’s why we are in 95 percent of Chicago hot dog stands. Our buns are designed for the Chicago-style hot dog. We’re proud of that.”