Rudolph's Specialty Bakeries' vacuum cooling chamber resembles a rack oven.

Rudolph's mixing room contains three mixers and an automated sourdough system that creates and maintains the company's sourdough

The vacuum cooling site consists of various pieces of equipment, such as a smoke eliminator, a vacuum pump, a vacuum chamber, an oil cooling system and PLC controls.

Rudolph's uses an extrusion divider because its dough is extremely sticky, and would not process in a ram-and-shear divider.

Rudolph's loaves exit their initial pre-bake.

From left to right: Howard Welshman and George Paech spent two and a half years perfecting the vacuum cooling system.

The science behind the technology is sound," George Paech, Rudolph's Specialty Bakeries' president, reassuringly says as he operates the controls on the bakery's latest technological innovation. When the system kicks on, one gets the sense that something really big is happening. Motors begin to hum, a cooling unit commences operation, a PLC starts flashing numbers and graphs onto a display panel, and broad smiles appear on the faces of Paech and Howard Welshman, Rudolph's plant manager.

Two and a half years of tinkering and testing are finally bearing the fruits of Paech's and Welshman's labor. The system they have designed and put through a barrage of tests uses vacuum technology to reduce the cooling time of the company's line of rye breads by about 7.5 hours.

This latest foray into innovative technology is nothing new for the Toronto, Canada-based bakery. Since its founding in 1952, Rudolph's has evolved from a hands-on pastry shop to an automated bakery employing unique baking technologies and techniques. The company also has morphed its approach to the baking business to conform to population and demographic trends.

Although the bakery's ties date back to 1604 in Germany, the bakery's North American operations did not evolve until post World War II. After dabbling in pastries for ten years, Paech's father changed the direction of the bakery and began producing rye bread to satiate the demands of a growing Central European population in North America.

"We provided them (European immigrants) with what they knew as food from home," Paech says. "It was a ready-made market."

Using rye bread recipes originated in Germany, Rudolph's has grown from a local bread producer to a major player in the rye bread business, supplying products in Canada, Northeastern United States, and as far as Florida and California. Throughout this growth period, the company has automated its plant and sought new technologies and techniques that allow it to ramp production without changing its formulas.

Its latest investment in technology is a vacuum cooling system that uses a loaf of bread's own heat to cool the loaf. Sound confusing? It is.

Double crust
 Before explaining the science of vacuum cooling and its benefits to Rudolph's, it's important to understand why the bakery needs anywhere from 6 to 10 hours to cool its products. The company manufactures traditional rye breads that range in size from 13.2 lbs. to 22 lbs.

To produce this traditional German rye bread, the company employs a double bake, which forms a double crust. For the products' first bake, they travel through a small tunnel oven for five to six minutes at 800°F. "The first bake sears the loaf of bread, which seals the flavor and the moisture in," Welshman says. "After this first bake, you can already feel a crust on the product."

After the initial bake, the products are loaded into one of two revolving tray ovens where they bake on ceramic plates for about an hour. "We use a revolving tray oven because the heat is all in one place," Paech says. "With a tunnel oven, you have zones and inconsistencies." When producing a traditional double-crusted rye bread, inconsistencies in baking are unacceptable. For the company's line of lighter rye breads, it uses a standard tunnel oven for baking.

After the company's traditional rye breads finish their second bake, they need to be cooled before being sliced and packaged. Standard bread bakeries accomplish this task through spiral or racetrack cooling conveyors. Because Rudolph's bakes up to 22-lb. loaves of bread with double crusts, cooling the product in ambient air takes anywhere from 6 to 10 hours depending on the weather.

As a result, the company racked all of its breads and wheeled them into a storage room where large fans cooled the products down. This took up considerable space and led to inconsistencies in the product. "Cooling in ambient air with fans gives you uneven moisture distribution across the front of the bread because it is drying on one side and not the other."

The extended cooling time also resulted in an eight-hour gap in production from the time the products were baked until they were packaged. As a result, scheduling consecutive shifts was next to impossible.

To simplify the cooling process and operate a more efficient bakery, the company invested its money and time on a unique process that quickly cools large loaves of bread before being sliced and packaged for distribution.

Vacuum cooling
 Paech first got the idea to implement vacuum cooling technology at iba1998 in Munich, Germany, when a scientist presented a position paper on the topic. After a prototype of a vacuum cooling system was created in Germany in 2000, the company decided to go ahead with the project.

The science behind vacuum cooling says that a moisture-laden product can be cooled using its own heat energy. In English, this translates to a loaf of hot bread using its own heat to cool it off.

For this science to work, a moisture-laden product must be placed in an airtight chamber. Once in the chamber, a vacuum pump drastically lowers the pressure inside the chamber.

In ambient air, the pressure normally hovers around 1,000 millibars. At this pressure, water boils at 212°F. As pressure is reduced, lower temperatures are required to boil water.

"The way normal ambient cooling works is that water molecules turn into water vapor by the heat energy in the loaf. When this energy/temperature is reduced, it takes longer and longer to achieve a temperature reduction," Paech says. "When you reduce the pressure, you reduce the cooling time because you're causing water molecules, which now have a lower boiling point, to be energized by the energy you already put into the product by baking it. As the temperature is lowered, less energy is available. However, you do not require as much heat because of the lowered boiling point of water. We're cooling the product with its own heat. We've imparted the energy by baking, and now we're going to use that energy that's residual in the product to cool it."

That's the science behind vacuum cooling. To turn the science into a working system, Rudolph's enlisted the services of a European equipment supplier to build a system based on specifications supplied by Rudolph's. Once the system was built and shipped to Toronto, Paech and Welshman took responsibility for making it work.

Vacuum cooling beta site
 The vacuum cooling beta site at Rudolph's bakery is surprisingly unnoticeable for the magnitude of the project. It resides about 25 yards from the oven and takes up roughly 1,000 sq. ft. The cornerstone of the system is a chamber that resembles a rack oven, only more imposing. According to Paech, the door of the system weighs a ton and each of the walls weigh 2.5 tons.

Besides the vacuum chamber, the vacuum cooling system requires other pieces of equipment, including a smoke eliminator to reduce exhaust, a vacuum pump to power the vacuum chamber, an oil cooling system, and PLC controls.

Together, all of these pieces form a complicated system of technology that reduces the company's cooling time from eight hours to 28 minutes. It accomplishes this feat by lowering the pressure in the vacuum chamber from 1,000 millibars to 40 millibars, a pressure where water boils at 95°F.

To operate the system, a double-rack of loaves is wheeled into the chamber. Because the technology for vacuum cooling is relatively new, the company did not want to take the risk of building a larger system or one that could run inline. "We wanted something that was manageable," Paech says. "So this acts as sort of a bench model."

Once the rack of loaves is in the chamber, the vacuum pump kicks on and begins lowering the pressure inside the chamber. For the next 28 minutes, the pressure inside of the chamber lowers from 1,000 millibars to 40 millibars and then back up to 1,000 millibars.

"You have to bring the pressure down on a curve," Welshman says. "You can do things too quickly or too slowly, and there was no data on any of that."

According to Paech, Rudolph's is one of the first bakeries in the world to use vacuum cooling to cool fully baked loaves before slicing. However, the technology has been used in other areas of the baking industry, mainly to cool par-baked loaves.

Because no parameters existed for cooling 22-lb. loaves of bread before slicing, Rudolph's conducted tests for a year to determine the best method for vacuum cooling each of the company's 28 skus.

Front of the line
 Although the back end of Rudolph's production line is chock full of innovative technologies and techniques, the company also has invested heavily in the front end of the line. The centerpiece of the front of the line is an Ismar sourdough system that the company purchased five years ago. The system consists of two sourdough tanks that receive organic flour, water and a starter culture. The temperature-controlled tanks constantly agitate the sourdough and feed it to the mixing bowl when called for.

According to Paech, an ideal rye bread always starts with a sourdough. "If you were to just take rye and water and mix them, it would have no flavor," Paech says. "However, if you put that together with a sourdough, which releases the enzymes and thereby the flavor of the rye flour, you get a completely different product."

After depositing the sourdough in the mixing bowl, an operator moves the bowl to one of three vertical mixers. After mixing, the dough is elevated into a hopper and chunked before entering an extrusion divider. The company uses the extrusion divider because its dough is extremely sticky, and would not process in a ram-and-shear divider. The divider extrudes the dough into a sausage shape before cutting it. After cutting, the dough travels through a series of rounders.

Reaping the benefits
 Rudolph's willingness to invest time and money into new technology has allowed the company to take a shrinking market and turn it into a solid business. "The population of hardcore rye bread consumers is going down. There's a reason why we're in the rye bread business and not a lot of other people are," Paech says. "We have a certain skill set and it works for us, and we have a lot of time and energy invested in that."

Rudolph's also has a vested interest in taking risks. Spending two and a half years developing a unique technology that had no guidebook or parameters is an enormous risk. However, Paech and Welshman were not afraid to take that risk, and in the end, they expect the investment will be well worth it. Already, the new vacuum cooling system has greatly reduced the cooling time of its bread. It also has allowed the company to take its breads to market quicker. "The whole idea is to compress our production schedule," Paech says. "Right now, we have an interval of eight to ten hours between baking and slicing. When we can bring those eight to ten hours together, we have a better product going to market."

And, the company expects to realize even more benefits of the vacuum cooling system as time passes. To Paech, this makes the investment an ideal business move. On a more personal level, the investment has increased his love for baking bread.

"To just run a plant day in and day out, it doesn't tweak the imagination," Paech says. "If you're bored, you do one of two things: Either fire somebody or redecorate your office."

With more innovative ideas on the horizon, Paech does not plan to redecorate his office anytime soon.