Snack and Bakery

Cryogenic flour chilling system helps Coles make quality frozen breads -- with a twist

September 9, 2013
September Case Study

Founded as a neighborhood bakery in 1943, Coles Quality Foods, Inc. (Grand Rapids, Mich.) became synonymous with frozen garlic bread when it established the category in the 1970s. Today, Coles offers a complete line of frozen bread -- including mouthwatering Big Texan® toast, cheesesticks and breadsticks  – “that goes from freezer to table in 10 minutes or less.”

Cold processing is critical to Coles’ product quality and coast-to-coast success.  All Coles products have a one-year frozen shelf-life.  Cases are shipped to national distribution centers and sold through major supermarkets including: Shop-Rite, Winn-Dixie, Wal-Mart, Piggly-Wiggly, Kroger, Food Lion, Meijer, and others. Increasing demand for Coles’ unique frozen breads tested Coles’ North Liberty, Iowa, production operations in the summer of 2012. 

“The driving force for us in wanting to make a change was extrusion quality,” says Aaron Scott, plant manager of Coles baking and freeze processing facility in North Liberty, Iowa.  Coles makes breadsticks and cheesesticks with a twist through a proprietary extrusion process.  The twist is a brand hallmark.   

After dough is mixed and processed through the proprietary extrusion systems, Coles proofs product prior to baking, then applies the toppings. Breads then move by conveyor to a Linde cryogenic spiral freezer for a highly controlled freeze with carbon dioxide (CO2).  “The spiral works well for that at the volumes we are running,” says Scott, who previously worked for an international yeast supplier. “But we were experiencing issues with the dough going into our extrusion and finishing operations.” Linde North America (Murray Hill / New Providence, N.J.) reached out to Coles last year. 

The plant performs continuous quality control, and samples product hourly to monitor processes. Problems with the dough though, can be visible, especially during and after extrusion operations. “We then need to discard product before it goes through the applicator and into the spiral.  That can slow you down.  And no one likes to discard product, because at that point, you’ve lost not only the ingredients, but all the overhead that went into production.”

Following the in-plant assessment, the Linde Food Team recommended an in-line cryogenic flour chilling system to achieve more consistent dough mixing performance.  Like many well-established bakeries, the plant had relied on chilling the mixer with water ice in warmer weather, particularly from May to October.  An operator would retrieve two 25 lb. bags of ice from a machine (one flight down) and pour the ice into the 1,000 lb. Peerless mixer, with a new mixing cycle every 20 to 30 minutes.  First, the dry ingredients would be added, then the liquids, with the water portion of the recipe adjusted down to compensate for the ice.

Scott scheduled the installation of the new flour chilling system during a planned holiday weekend ahead of the Spring warm up.  The Linde system injects liquid CO2 into the pneumatic system as flour is conveyed to the mixer from an outdoor silo through a four-inch line. The temperature of the flour is continuously monitored just before the inlet to the mixing vessel, and a feedback system controls the precise injection of CO2 to ensure a consistent flour temperature to within +/- 1 degree F of the setpoint. The precision feedback system also minimizes cryogen use to keep operating costs low. 

Linde installed the chilling system including all supply lines and venting over an extended weekend (Friday to Sunday), and trained the staff on the system’s operation and safety when they returned on Monday. The use of cryogenics takes advantage of the existing CO2 supply (used to freeze the final product in a cryogenic spiral freezer) and provides for improved mixer operation, eliminating all the variations associated with the ice chilling. Product losses were reduced 0.2 percent -- significant in a high-volume operation like Coles.  And since there is no ice to carry, a worker safety issue was also eliminated.

Cryogenic control of incoming flour temperatures can also mean more consistent baking performance.  Leavening agents are sensitive to warmer temperatures, a point not lost on Scott with his yeast supplier experience. And quality is always the bottom line at Coles. Consistent batch-to-batch dough quality means smoother year-round production – from mixing all the way to the signature twist.