Yeast-raised baked foods require a distinct environment for the dough to rise to its optimum volume and to prove that the leavening agent works. This atmosphere is found in the final proofer, one of the last processing steps prior to baking.

Final proofers come in many shapes and sizes, and often, the product determines the style of proofer. For example, yeast-raised donuts often are proofed in tray-style systems, while flatbreads generally traverse cascading-style proofers. Of course, many bakeries rely on roll-in rack proofers that impart flexibility by allowing bakers to easily adjust proof times.

Rack-style proofers also can be designed as first-in, first-out traveling systems that hold multiple racks at a time. High-speed bread and bun lines commonly use conveyorized proofers. Bakeries also can select from spiral or tunnel proofers, and space limitations may influence a bakery’s choice.

Stable environments

Product consistency has been and likely always will be the greatest challenge with not only proofing but the entire process, said Scott McCally, mechanical engineer, thermal systems, Stewart Systems, Plano, TX. “At the proofer and its neighboring oven, we get to critique what we feel, see, taste and smell,” he explained. “What we have in our possession is the chemically transformed product that has been developed over a long process and now looks like something familiar.”

As such, a baker might see overproofed product spilling out of baking pans. In this situation, it’s not uncommon for the line supervisor to quickly make time or temperature adjustments at the control panel to see the proofer’s response.

“Unfortunately, much like taking aspirin for a body ache, this response merely treats the symptom and not the cause,” Mr. McCally explained. “The real cause could be from potential problems inherent to the process — for example, too much yeast is used, the ambient bakery temperature is too high, or pans are returning too hot. There could have been a slowdown in the product throughput or any number of issues. Of course, it could be the proofer, too.”

Stewart Systems aims to provide the valuable information that quickly lets the operator know either “Yes, it is the proofer, or “No, look elsewhere.” “Our proofer allows the operator to treat the symptom so that all is not lost; however, it also provides the diagnostics for quick and appropriate decision making,” Mr. McCally added.

Bakeries want proof boxes that maintain a steady environment throughout the proofer. “Consistent temperature and humidity are critical to producing a consistent product,” said Eric Riggle, vice-president, Rademaker USA, Hudson, OH.

To give bakers tighter control tolerances within proofers without the added cost of modulating valves or proportional-integral-derivative (PID) controllers, The Fred D. Pfening Co. introduced its Model B4 digital proof box control. “The Model B4 control mimics the characteristics of modulating valves using on/off solenoid valves by activating them for a percentage of a given time period instead of opening a modulating valve a varying percentage,” said Brian Doan, project engineer at the Columbus, OH-based equipment manufacturers.

The control box features a large display of both temperature and relative humidity and offers the ability to lock out set-point changes to unauthorized personnel.

AMF Bakery Systems, Richmond, VA, provides several options for adding heat and humidity to the proofer. “Depending on the customer and plant location, we supply heat from steam, electric or reclaimed heat and humidity from steam and atomized spray,” said Phil Domenicucci, AMF’s executive product manager, final proofers and ovens.

Bakers frequently ask how they can reduce energy for final proofing because they would like to forgo the need for steam boilers, he added. “Since there is a large amount of moisture going up the chimney, we are looking into reclaiming energy from that moisture,” Mr. Domenicucci said.

Sanitation options

In addition to providing uniform temperature and humidity control, today’s proofers must be easy to clean, allow quick changeovers and provide operating efficiency. “Moline proofers achieve all of these requirements while ensuring operator safety,” said David Moline, sales and marketing manager, Moline Machinery, LLC, Duluth, MN. “Moline proofer systems are all fitted with graphic diagnostic screens for easy operation and quick troubleshooting — both of which lead to maximum uptime. Moline also offers clean-in-place systems for all proofer models, which allows quick and efficient sanitation.”

Over the past several years, Pfening changed its steam piping assemblies to make them easier to take apart and maintain. “We also take great care in laying out custom proofer conditioning systems that provide access for sanitation and maintenance,” Mr. Doan said.

IJ White, Farmington, NY, offers a Total Cleaning Package (TCP) with its Accu-Proof Systems. TCP provides three-stage (rinse, wash and sanitize) cleaning of the system. “Using strategically placed spray balls and multi-zone cleaning, TCP can provide a level of sanitation and hygiene never before achievable in traditional conveyorized proofers,” said Peter White, IJ White’s president.

Also, he pointed out that the centralized, semi-automated cleaning system reduces man-hours and lowers costs, while meeting bakeries’ needs for a higher level of hygiene within their plants.

“Time is money — it’s the cliché that high-volume bakers lose sleep over,” Mr. McCally said, noting that bakers want minimal downtime cause by machine error.

To reduce downtime, Stewart Systems developed high-performance lubrication and hardened track curves for its conveyorized proofing systems. “A high-performance engine will fail within minutes without proper lubrication. So will our high-performance proofer chain — within days,” he said. “We have developed a private-label lube that outperforms all others in the key metrics. In fact, it’s so effective we doubled the chain warranty with its usage.”

Proofer chains start to get jumpy when they wear into the track, and operators most likely should start checking at the curves where chain load is the highest. “At Stewart Systems, our first set of hardened track curves shipped in 2006, and they are still holding strong today,” he said. “Check back again around 2020 for an update.”

Simple controls

Designing optimal proofing systems to be as economical as possible remains one of Pfening’s greatest challenges, according to Mr. Doan. “In every design, there are trade-offs between optimal design and cost,” he said. “We are working to find innovative ways to save cost without sacrificing quality.”

Also, he pointed out that Pfening explores ways to make its proofers more energy efficient and has begun an initiative to build corrosion-resistant proofers using different materials for critical components.

Stewart Systems continually seeks to add more monitoring and feedback programs to its systems as well as the ability to quickly and appropriately react to that feedback, Mr. McCally said.

There are many systems inside and outside of a proof box, and each system’s internal diagnostics lets operators know that everything is going well. “Of course, all of this is happening largely in the background of the control system so as not to overwhelm the operator,” he said. “Our aim is to keep the controls simple to operate but with the flexibility to proof nearly any recipe imaginable.”

While Moline originally designed its tray-style proofer for donut production, new technology that efficiently discharges products from trays for even and smooth delivery to the oven or fryer allows it to be used with a wider variety of yeast-raised baked foods. “Our proven discharge systems in tray-style proofers provide gentle, smooth product transfer from trays to prevent damage or malformation,” Mr. Moline said.

In addition, Moline recently released belt-style proofers that house multiple tiers of conveyors within a temperature- and humidity-controlled environment. This cascading-style proofer has traditionally handled flatbreads, pizza crusts, wraps and the like, but Mr. Moline noted that it can be put to work for many other types of product as well. “Moline designed these proofers to use all belting types ranging from the typical mesh-style belt to traditional fabric and plastic belting,” he observed.

Because a poor transfer can ruin products, bakers demand precise product placement. “Moline pays careful attention during the design phase to optimize product transfers, which are especially significant in the belt-style proofers, so the product does not deform during transfer,” Mr. Moline said.

Rademaker’s cascading proofers have the ability to transfer full dough sheets as well as cut products — either round, square or rectangular in shape — through the proof box. “Rademaker provides a unique and adjustably-driven tier-to-tier transfer system that greatly reduces, if not eliminates, blunt or flat ends,” Mr. Riggle said.

With the activation of a switch, a fully automatic belt tensioning system for the company’s cascading proof box disengages all of the rollers to loosen the belts, thereby making it quicker and easier to clean the proofer.

Heat, humidity and time represent the key variables for final proofing that ensure yeast-raised baked foods rise to the occasion. Today’s systems continue to include new controls and features to make running these pieces of equipment easier than ever before.