Making it Foolproof
March 2, 2011
by Shane Whitaker
Proofers are not something bakers think about changing out every few years. Jeff Dearduff, director, US bakery operations, East Balt, Inc., Chicago, IL, said bakers have about 20 years of service in mind when purchasing a proofing system.
Because the proofer is such a long-term investment, some companies may not be aware of the latest innovations in proofing technology, and proofers — especially for breads and buns — have come a long way in the past 15 years, according to Mr. Dearduff.
The two things bakeries desire the most from proofers are consistency and control. They want to be able to set the heat and humidity in the proofer and not worry about getting away from its set points. Bakeries also want proof boxes that are easily sanitized. And thanks to the latest advances in proofers, bakeries can find proofers with greater controls and that are easier to clean.
Temperature control is the most difficult element to manage in older proof boxes, according to Mr. Dearduff. Often, bakeries were designed with insufficient pan cooling systems, and frequently, he said, this is overlooked as a chief reason for proofer temperature control problems When hot steel pans re-enter the proof box at temperatures higher than the desired proofing range, then the proofer becomes, in effect, a pan cooler with the pans its main heat source, Mr. Dearduff added.
“This problem, which exists in many plants, is only overcome when people are truly convinced of the problem,” he said. “Longer pan cooling conveyor circuits or special forced-air coolers that can bring the pan temperature below that of the desired proofing temperature will solve this problem.”
Mr. Dearduff noted mechanical air-conditioning systems have been added to the proofers’ air makeup systems, but this creates a new problem because cooling tends to dehumidify the moist atmosphere that bakeries are trying to create and maintain.
However, C.H. Babb Co., Raynham, MA, recently added refrigeration systems to its proofers, allowing them to offer a high level of control over temperature and humidity, according to Charles Foran, the company’s president.
The biggest challenges in proofing are maintaining proper temperature and humidity, he said. This is especially so on hot days in bakeries, when proofers will retain even more heat, causing the customer to lose control of the proofer.
C.H. Babb designed an improved air distribution system that keeps the proofer at even conditions from top to bottom, Mr. Foran added.
The Fred D. Pfening Co., Columbus, OH, also has included cooling in its proofers on occasion, according to Brian K. Doan, project engineer at the company. “Some specialty products require cooler proofing temperatures, as low as 85° F,” he said. “In some cases, direct steam injection, seasonal changes or hot pans coming back from the oven can cause temperature overshoot. In those cases, it may be necessary to use air conditioning and/or an alternate humidity source to help maintain better control.”
Pfening employs custom PLCs and the new Pfening Model B4 digital control to help bakers more closely regulate the proofer’s temperature and humidity, Mr. Doan noted.
The new digital control uses on/off solenoid valves. “They open for a percentage of a given time period, which keeps the proofers from overshooting their set-point as much,” he explained. “This type of control can be achieved with some generic controls, but they are usually difficult to use and require setting many different parameters. The Pfening Model B Control only requires setting six parameters.”
Pfennig’s proofer control manages heat and humidity independently using a single control module. “We do restrict humidification below 90% of the dry heat set-point,” Mr. Doan added. “This allows the proofer to be warmed up much faster when started cold. Also, at lower temperatures, the air cannot hold as much moisture.”
Efficiently maintaining optimal temperature and humidity control with inconsistent volume throughput is the greatest proofing challenge to bakeries, according to Rick Rodarte, director of engineering, Stewart Systems, Plano, TX.
“A fluctuating load requires dynamic responsiveness from the proofer’s conditioning unit to maintain consistent high-quality product output,” he said. “Stewart Systems’ Proportional Integral Derivative control system (PID controller) adjusts output quickly under even the slightest change in load. Our robust conditioner can provide dry-heated or cooled air — a variable-speed recirculation blower directs hot-steam or cool-misted atomized air through a cross-flow-ducted air system producing a consistent proof of every pan regardless of load. This quick-response system minimizes the total amount of input resources, namely energy and water, needed to maintain the proper proof environment in unsteady state conditions.”
Stewart Systems recently worked with a bakery customer to develop a custom conditioning system that uses fresh air intakes as part of the environmental control for the proofer. “This is unique because the fresh air is utilized directly as a control feature as opposed to using cooling coils or water misters,” Mr. Rodarte said.
AMF Bakery Systems, Richmond, VA, added optional methods of heat and humidity to its proofers. “Depending on the customer and plant location, we supply heat from steam, electric or reclaimed heat, and humidity from steam and atomized sprays,” said Phil Domenicucci, AMF’s executive product manager, final proofers and ovens.
Additionally, he pointed out that bakers are asking how to reduce energy for final proofing and for alternative sources for heat and humidity because they would like to forego the need for stream boilers. “Because there is a large amount of moisture going up the chimney, we are looking into reclaiming energy from that moisture,” he said.
I.J. White Systems, Farmingdale, NY, offers two versions of its Humidity Control System for spiral proofers. It’s available as either Direct Steam Injection into the air stream or as Vector Misting that controls humidity by adding water into the enclosure at various locations and levels. Both have advantages, depending on the product requirements, noted Peter White, the company’s president.
The Capstep from Capway Systems, York, PA, offers a space-saving design that can handle wide pans and/or boards. Pans enter at the bottom of the elevator section. They climb up 35 levels in a step pattern and then back down, with all movements of the Capstep based on preset proof or cycle times.
A current trend among bakers, Frank Atcherberg, Capway’s president, noted, is for longer proof times at lower temperatures. This requires air-conditioning to ensure the temperature can be controlled and does not override the set point, he said, pointing out the Capstep offers a reliable and consistent proof.
On dedicated lines, bakers of bagels and sandwich thins are looking at eliminating carriers and boards, according to Mr. White. “Accu-Proof 7000 is engineered to proof these products directly on the belt,” he said. “This dramatically reduces the costs of buying, cleaning and maintaining boards, pans or paper in traditional systems.”
Also, bakers are demanding more flexibility in the types of products that a proofer can handle. “This can require multiple types of carriers on the same line,” Mr. White said. “Accu-Proof can convey strap pans, boards and aluminum foils all on the same system.”
I.J. White expects bakers to be able to proof more products on the belt as its Accu-Proof technology improves. “This will eliminate the expensive carriers and the high cost of maintaining and cleaning the pans, trays and boards,” Mr. White added.
Because AMF manufactures equipment for makeup, proofing/baking and packaging/distribution, it can offer total integration of the entire plant, Mr. Domenicucci said, and that significantly reduces the risk of trying to combine systems from multiple vendors.
In the future, bakeries will look for proofers to become more environmentally friendly, predicted Mr. Doan, noting that Pfening has already completed projects that use alternative heat sources such oven exhaust to heat the proofer. “I believe that conservation of steam/water used for humidification will become more important as well,” he said.
AMF’s Mr. Domenicucci added, “As sustainability puts more pressure to improve energy consumption in bakeries, we have to look at more efficient ways of reclaiming lost heat like using the heat of condensation from oven exhausts. In addition, we have to develop better methods of monitoring steam quality to maintain more consistent saturation.”
Equipment manufacturers have responded to bakers needs, and proofers have undergone a number of improvements in recent years helping bakers to achieve better control of heat and humidity and also greater access for sanitation. So if it’s time to look at replacing your older proofer, there are lots of new options to consider in the latest systems.