How potato flakes are made

Meta-description: The process behind the crafting of potato flakes and the crucial role of drum dryers
Potato flakes are flat chunks of dehydrated potatoes. They are the main ingredient in instant mashed potato products and others. Their main advantage is that they can be easily dehydrated using cold or hot water and used in various recipes.
Have you ever wondered how potato flakes, or powder, are made? The process revolves around the use of a drum dryer, and in this article, we’re walking you through every step of it.

The process behind making potato flakes
As we’ve mentioned, roller dryers are at the base of the potato flakes-making process. However, when potatoes enter the drum dryer machine, they have already been subject to a series of steps, from selection and cleaning to drying and packing. Each of them must be optimized to obtain the best final product.
We can break down the process of making potato flakes as follows.

Step 1: Selection
When it comes to food, the quality of any final product depends largely on the quality of the raw material, and potato flakes are no exception.  
Different types of potatoes have different characteristics. They vary in dry material content percentages, internal color, buds' depth, reducing sugar content, solanine content, and polyphenol oxidase content. All these characteristics have a different impact on the finished product, for example:

• Potatoes that are rich in dry matter have a high flour yield.
• Potatoes with many and deep buds have a lower yield.
• When the reducing sugar content is high, the finished product will be dark in color. The same stands for polyphenol oxidase content.
• When the solanine content is high, the toxin removal process would be difficult.

Now you can better understand why the potato selection phase is important to optimize the process and obtain the best result possible. The best potatoes to make potato flakes or powder (sometimes known as potato flour as well) are the ones with a good shape, shallow bud eyes, white flesh color, low reducing sugar content, and low solanine content.
However, the selection process doesn’t stop here: raw materials are always weighed and still further selected to remove moldy potatoes and rotten pieces.

Step 2: Stone removal and cleaning
Potatoes are moved from storage to a silo and then conveyed to a destoner via a belt elevator. Here, impurities like stones and sand are separated as they sink in a cyclone barrel, while potatoes float.
The cleaned potatoes are then scrubbed in a drum cleaning machine and subsequently dehydrated in a vibrating dehydrator. After this, they are conveyed to a steam peeling system.
The water used from these processes is filtered and recycled, ensuring efficient usage. This system efficiently cleans potatoes while separating waste and recycling water, streamlining the preparation for further processing.

Step 3: Peeling
In the peeling stage, potatoes undergo a series of processes to remove stones and impurities and ensure thorough cleaning. The different passages can be summarized as follows:

• Potatoes are transported from storage to a silo.
• An adjustable speed screw conveyor moves potatoes to a belt elevator beneath the silo.
• The elevator lifts potatoes to a destoner, where backwash water causes potatoes to float, while heavier impurities sink.
• Sunk impurities are removed via an inclined belt conveyor to a waste hopper.
• Potatoes and water flow through a chute into a drum cleaning machine, where they scrub against each other as the drum rotates.
• Cleaned potatoes are transferred to a vibrating dehydrator for water separation.
• They are then conveyed to a steam peeling machine.
• Water from cleaning and dehydration is filtered, removing impurities.
• Filtered water is recycled back to the destoner through a recovery pool, optimizing water use.

Step 4: Intermediate Hopper
Potatoes proceed to an intermediate hopper via a flow-equalizing screw conveyor for temporary storage, allowing continuous production. Equipment is cleaned, maintained, and monitored, with a liquid level sensor in the hopper halting operations when full.
Potatoes are then transported for further processing via a continuous system equipped with a flow control mechanism.

Step 5: Slicing
The slicer cuts potatoes into slices that are 10-12mm thick, with the thickness varying based on the size of the potato. For smaller potatoes, thinner slices are produced, while thicker slices are made for larger ones. The aim is to achieve uniformity in slice thickness.

Step 6: Dehydration
Following washing, the potato slices proceed to the vibrating dehydrator for the removal of excess moisture and separation of small potato pieces. Once dehydrated, the potatoes move on to the next stage of the process.

Step 7: Blanching
Dehydrated potato slices are fed into a horizontal spiral blanching machine filled with hot water (65-75°C) for about 20 minutes. This process gelatinizes starch, maintaining potato cell structure while enhancing intercellular communication. The machine's pump circulation system and temperature control mechanisms ensure uniform blanching. A rotary mechanism removes potato slices and transfers them to a cooler via a conveyor chute.

Step 8: Cooling
Post-blanching, potato slices enter a horizontal spiral cooler, gradually reducing starch expansion. Cooling occurs in cold water, ideally at 20°C, for about 20 minutes, facilitated by a pump circulation system. Water level and temperature are regulated by an overflow tank mechanism. A wheel mechanism removes cooled slices, transferring them to the next stage via a screw conveyor and rotary valve feeder.

Step 9: Steaming
In the steaming process, a spiral cooking machine controls cooking time by adjusting its rotation speed, typically ranging from 20 to 40 minutes for various potato varieties. Operating at normal pressure with 4 bar saturated steam at 100°C, the machine utilizes a temperature transmitter and pneumatic valve to automatically regulate cooking temperature. Adjustments to steam injection maintain consistent cooking conditions.

Step 10: Mash
Cooked potato slices enter a masher via a screw conveyor, where an additive device injects a predetermined mixture. A structured tamping plate compresses the chips, forming mashed potatoes. The mash proceeds to a drum dryer for further processing.

​Step 11: Drying 
Mashed potatoes are spread evenly on a drum dryer's spiral, with dressing rollers adjusting gaps to remove impurities. A heating system maintains drum temperature. Controlled scraping devices transfer mashed potatoes between rollers, while dried film is scraped off for pre-pulverization. Two steam heating systems ensure efficient operation.

Step 12: Smash
Pre-crushed snowflakes are pneumatically transported to a crusher, where an inspection belt manually checks for defects. Qualified products are conveyed to the finished product warehouse via a pneumatic system.

Step 13: Finished Product Warehouse
The warehouse receives potato powder flakes, delivering them to packaging machines via a conveyor spiral. Dust is collected and treated, with waste gas discharged through an exhaust fan. The warehouse stores at least 2 hours of output.

Conclusion
This comprehensive article has delved into the intricate process of creating potato flakes, emphasizing the pivotal role of drum dryers throughout the production, and showing the complexity involved in crafting this ubiquitous kitchen staple.