Power sources, sanitation needs and new technology are among the key issues to consider when choosing frying equipment.
“We think the best fryer for donuts is a surface fryer design in either gas or electric,” says John DeMarre, vice president, industrial and international sales, Belshaw Brothers, Seattle, Wash.
Choosing natural gas or electric fryers depends on a bakery’s priorities. More gas than electric fryers are sold in the United States because of the availability of gas and the price of gas versus electricity, DeMarre says. “Gas, while it is a little bit more involved to clean and maintain, is also more efficient to operate. It recovers faster. It will maintain temperature in the fryer just a little more accurately than an electric fryer,” he adds.
Gas fryers cost more to insure than electric fryers, and electric fryers are typically less expensive to buy compared to gas fryers, DeMarre notes.
“The electric heating elements in an electric fryer get very hot and tend to break down the oil. In a gas fryer, you can modulate the gas flame and thus the temperature of the emersion tube in the oil, so you don’t break down the oil as much,” says Damian Morabito, president, Topos Mondial, Pottstown, Pa. Topos Mondial makes new gas fryers and re-manufactures used gas fryers, incorporating the latest technology.
The location of a bakery also comes into play when choosing a fryer because natural gas fryers cannot be used in certain locations where natural gas is not available, Morabito says.
“Electric fryers are less expensive to install,” DeMarre notes. “They are also easier to maintain. They are simpler to clean, so it costs less to clean them. The lifespan of an electric fryer is indefinite, where [with] a gas fryer, eventually, you’re going to have to deal with either a heat exchanger replacement or a fry kettle replacement,” he says. DeMarre adds that bakers who can afford to use electricity or are limited to using electricity will be well served by an electrical fryer. In addition, oil lasts longer in an electrical fryer.
DeMarre says most new advancements in electrical frying equipment are in programming capabilities. The use of program logical controllers (PLCs), which have become the norm first on large and then on mid-size fryers, allow operators to control the entire frying operation from the panel view on a touch screen. “A PLC can do a lot more than simply indicate the status of your operation. It can indicate the status of maintenance. It can tell you whether motors need to be serviced. It can tell you when the fryer should be cleaned,” DeMarre says.
“A PLC has a feedback function and can tell the operator a lot of what is happening with the system that normally would not be available to the operator. That helps to improve the service intervals and the quality of service on the equipment and gives the bakery a longer lasting piece of gear as a result of that. Advancements have been made to improve the information available through that process,” he adds.
Morabito says bakers are more concerned with sanitation issues than in years past. Innovations in gas fired surface donut fryers make it easier to clean both the kettle and the exterior of the fryer. Adding the conveyor “elevator,” which takes the surface frying conveyor in and out of the kettle, also has simplified cleaning.
In addition, advancements in temperature controls, including newer digital controls and more accurate temperature sensing are improving the performance of gas fryers, Morabito adds. “The temperature where the tubes are is typically hotter than where the frying is actually occurring, so it has always been a challenge to make fryers control [temperature] accurately and be efficient that way,” he says.
When it comes to the engineering of the frying kettle itself, kettles are now more shallow. “How the heat is brought into the kettle or into the oil and then how that oil gets its heat up to the product has been advanced, keeping a more shallow kettle design,” Morabito says. “A deep frying kettle causes more heat stratification in the depth of the frying oil, where there can be wide temperature swings in the frying oil from the top to the bottom.This makes temperature control at the frying surface in the deeper kettles harder,” he adds.
In addition, different shapes and types of tubes are being used to help transfer heat more efficiently, and the bearing materials that hold the shafts in the surface conveyor have improved, Morabito notes.
Many donut producers are moving towards remote gas fired fryers. “Most donut fryers today are direct gas fired fryers, which [use] a flame right at the fryer point. That flame heats up a tube that is in the oil,” Morabito says. “People in the donut frying world are starting to embrace some of the remote heated oil fryers. In other words a remote boiler is heating up oil. It’s pumping this heated oil into the kettle. And hot oil is being circulated from the boiler through the kettle, heating up the product, coming back and being filtered. The reason for that is safety and sanitation issues,” he adds. Morabito says this is a safer design because the flame is not near the fat at the point of frying. It is more sanitary because the burner manifold is not directly underneath the kettle. However, it is a more expensive design and can be less efficient because it requires more energy to circulate the oil.
“Some of the indirect fryers do not need fire suppression hoods right over them because there’s no flame underneath the oil and there’s no way for the oil to combust and catch fire. It’s contained within a boiler in a boiler room or a mechanical room separate from the fryer,” he adds.
Making a purchase
A good commercial gas fryer can cost from $200,000 to $500,000 for larger models, Morabito says. Gas fryers cost about 10 percent more than electric in any given size, DeMarre adds. Bakers on a budget might consider opting for a re-manufactured gas fryer, which can cost 60 percent to 70 percent less than a new fryer. During the re-manufacturing process, the controls and temperature sensing are fully updated, and the machine is adapted to be more sanitation friendly, Morabito says. “On a re-manufactured fryer, you can get a lot of the new features, but you are restricted by the original kettle design. We can modify and customize the surface conveyors to your needs [without a] problem. You are restricted by the overall original existing machine size,” he adds. “In re-manufacturing, the original kettle can be reinforced and re-fabricated so that ‘leaking’ kettles will be minimized or eliminated altogether.”
Plan for current and future bakery production needs when shopping for new frying equipment. Before visiting a frying equipment supplier, DeMarre recommends that manufacturers identify their production per hour requirement, the weight and dimensions of the product they will be frying and the fry time, or in the case of yeast raised donuts, the proof time. “Once we know the number of items they want to fry in one hour, the weights and dimensions and the type of handling characteristics of their product, we can ensure they get a fryer that’s right for them,” he says.
Bakers should be sure the surface fryer is configured properly for the products they plan to fry. “If you’re frying a lot of little products like donut holes or mini donuts or donut gems, small ring donuts, that’s one type of flight spacing and design. If you’re frying very large diameter products you would make sure the surface conveyor has a larger flight spacing,” Morabito explains. “[If] you want to do large products, but also small, there needs to be some kind of compromise made there, but to get the most efficiency out of the fryer you want to match the surface conveyor flight pitch, as we call it, or flight size to the products you’re frying so you get the maximum amount of product on the frying surface” he adds.
“On our new fryers and some older models, you can have a variable timing donut turner, which helps accommodate the turning of all sizes of donuts,” Morabito says. “This system allows the operator to adjust a) the position of the infeed flight bars relative to the turner position, b) the position of the turner itself and c) the position of the exiting flight bars relative to the turner position. All of these adjustments can be made while the fryer is running and without the use of tools. This gives the operator the maximum control of the fryer surface conveyor, allowing them to handle a wider range of product sizes efficiently,” he adds.
In addition, bakers should note whether the fryer is designed for easy cleaning. Does the surface conveyor rise up out of the kettle for cleaning inside the kettle? Also observe the sanitary design around the bottom of the fryer to ensure there is easy access for cleaning under the fryer.
“Look at the fryer tube design to see how easy it is to clean under and around the tubes. Some fryers have the tubes so close together that it is impossible to clean under and around them properly. This is a problem that is very hard to live with in the plant. If you can not properly clean all around the immersion tubes, they become coated with carbon and this greatly reduces the fryer efficiency,” Morabito notes.
Finally, bakers should examine the efficiency of the kettle design and how much gas input is needed to fry a certain amount of product.
On the horizon
DeMarre says future advancements will include fine tuning the design of frying equipment to improve the longevity of fryers, making them less expensive to maintain and operate. “These PLC type controls that help the operator identify service issues deep down is what we call preventative maintenance. PLCs today have preventative maintenance programing in them that will alert the operator that a number of hours has passed. All of that lends to better reliability because you don’t experience breakdowns. You’re ahead of that whole process,” he says.
Morabito says there will be continual advancements in kettle design and temperature control and sensing. “As the electrical technology increases every year, the temperature sensing capabilities will get much better where we’re really closely controlling the temperature of the frying surface to the best it can,” he says.