Marel's AeroScalder revolutionizes non-contact scalding with moist hot air for gentle heating

While not recognizing today’s evisceration, cut-up and deboning departments, the poultry processor of the late 1960s would in most cases recognize the sights, sounds and smells of a modern poultry defeathering operation, albeit that the overhead conveyor would be moving much more quickly and pinners would be absent in most cases. Sixty years later, birds are still largely immersion scalded and feathers removed by rubber fingers mounted on contra-rotating discs.

Scalder developments
Spray and dry air scalding hasn’t been proven effective. The latest development in non-immersion scalding is the Marel AeroScalder, which uses moisturized hot air to scald products. AeroScalder, which can scald up to 15,000 products per hour, saves significant quantities of both water and energy while also reducing the risk of cross-contamination. As AeroScalder was launched relatively recently and as processing plants change their scalding and plucking systems once every twenty years or longer, most plants are still using immersion scalding systems.

Air agitation
Another immersion scalding difference our late sixties poultry processor would pick up upon entering a modern broiler or turkey processing plant is the use of compressed air as opposed to mechanical impellers to agitate the scald water. This saves space, allowing an extra run of track where the impellers would have been. Mechanical impellers are still used when waterfowl has to be processed, as these would otherwise float.

Temperature control
In the very early days, most product was offered for sale deep frozen. In those days on/off temperature control systems were the norm. Today, when in many markets of the world products are sold fresh, accurate temperature control of the scald water is a must. Marel proportional temperature control systems keep the scald water within very tight limits, ensuring top quality products. AeroScalder offers even more accurate and immediate temperature control.

Easier to live with
Development work on plucking systems has been to make these easier to own and maintain. Here one thinks of ease of cleaning and re-fingering. All Marel pluckers have extremely stable A-frames and are belt-driven, which helps keep noise levels down in what is a noisy department.

In the early days when products were largely sold whole, Stork (the company name at that time) decided to restrict the number of adjustment options, arguing that too many settings possibilities would only lead to mistakes. The company therefore decided to offer cabinet pluckers, where the only option was to wind cabinets in or out to accommodate larger or smaller products. The angle of the plucking beams in one cabinet on either side was fixed and determined according to the knowledge at the time. That philosophy remains unchanged and is still good for plucking standard broilers today.


Left All Round Plucker 1966, right a modern duck plucker 2025

Beam pluckers
Broilers have, however, become heavier and longer. To deal with this situation, Marel has beam pluckers with three or four individually adjustable beams per side. Beams and cabinets are mounted in A-frames, where the beams can be swung out, giving excellent access for cleaning and re-fingering.

Many plants now fix frequency controllers to drives on the breast side of the product. This allows the speed of rotation of the plucking discs to be varied, lowering the risk of damage to skin on the breast side of the product, where there are fewer feathers.

Attack pluckers and finishers
For broilers, Marel offers both attack and finishing cabinet pluckers. The difference between the two is that attack pluckers, which as the name would suggest are more aggressive, have sixteen (or eight) discs for each of the four rows with ten fingers per disc whereas finishing pluckers have twenty (or ten) discs with eight fingers per disc. These eight fingers fit onto a smaller disc, where the speed of rotation at the disc’s margin is lower, putting less force on the product. Marel recommends the same finger hardness for both attack and finishing pluckers.


Changing markets
As in the USA, Europe and Oceania, most birds are cut into portions with the lion’s share of breasts being filleted, plucking has become much less critical than in the early days when most products were sold whole. Then each poultry processor had its own in-house “plucking expert”. This has meant that manual pinners have largely disappeared. Poultry processors are happy to leave it to the machines, particularly if they have a Marel IRIS DF vision quality inspection system, which does not only pick up residual feathers but also bruises, torn skin and broken wings. Manual plucking and quality control tasks are nearly impossible to perform, as modern high-capacity plants operate at line speeds of 15,000 birds per hour.

Turkey and waterfowl pluckers
Marel turkey pluckers are the “big brothers” of their broiler equivalents, albeit that instead of discs they have conical finger holders to penetrate into the thicker pack of feathers typical for turkeys. One interesting machine in a turkey plucking line-up is the contramatic plucker, whose long thin fingers are fixed onto rotating shafts, one each side of the product.


Ducks and geese have not been forgotten either. Depending on capacity levels, waterfowl processors can choose between in-line drum pluckers, regular pluckers (featuring six individually adjustable beams and the option of frequency control on those drives operating discs on the breast side of the product) and the contramatic plucker described above.

Sixty years from now?
Although there have been changes in plucker design, feathers are still removed by contra-rotating discs as in the late 1960s. Whether things will be the same in sixty years’ time is of course an open question. Poultry processors the world over can be sure of one thing. Marel will stay in the forefront of innovative developments in the scalding and plucking process.

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