How Corn Flakes are Made

In a bowl with milk, as a breadcrumb alternative and in recipes ranging from tarts to battered fish, corn flakes are incredibly versatile. So, how were corn flakes invented? And how are corn flakes manufactured? All is revealed in this guide to how corn flakes are made.

Engineering How It’s Made
24 August 2022

Before cereal, breakfast used to consist of leftovers from the night before and large cooked spreads. All that changed in the 1800s, with the invention of cooked cereals, followed by ones soaked overnight. However, it was the invention of corn flakes, or cornflakes, that turned the entire morning meal on its head. These toasted flakes of corn were the first ready-to-eat packaged breakfast, offering Americans and then the world, a convenient way to start their day.

Over the years, multitudes of cereal types have been created and breakfast is big business. So much so that Kellogg’s biggest European factory, based in Manchester, runs 24 hours a day, seven days a week, making over 30 million kilograms of the stuff every year.

So, how do they get it done? How are corn flakes made? More specifically, how are corn flakes produced in factories? We’ll explore how corn flakes are made and how are corn flakes manufactured. But first, a little history: how were corn flakes invented?

How Were Corn Flakes Invented? 

Starting the day the right way with cornflakes (Photo: VioletaStoimenova via Getty Images)

The question “how were corn flakes invented” has been answered many times. Confusingly, the answer is not always the same. The official story goes that it was an accidental discovery by brothers William Keith Kellogg and Dr. John Harvey Kellogg. They had been trying to create a healthy breakfast for patients at their sanitarium. One night in 1894, they were attempting to make a new type of bread when they flaked wheat berries. Inspired, they altered and experimented with flaking until they eventually flaked corn. The rest, as they say, is history.

Whilst it would lead them to revolutionise breakfast for people around the world, their discovery was also a source of animosity between the brothers. The original patent for corn flakes issued in 1896 was in the sole name of John Harvey Kellogg while the company that would bear the family name was founded by William. Both have different origin stories for corn flakes. Whatever led to their invention, corn flakes became an international sensation and Kellogg’s a household name. Today, Kellogg’s remains a leading light in the world of breakfast cereals.

So, now we know their origin story, how are corn flakes made today?

How are Corn Flakes Produced in Factories?

Kellogg's Corn Flakes production line (Photo: Jeff Greenberg via Getty Images)

How corn flakes are made in factories is a smoothly run, meticulous process involving highly automated production lines, lots of stainless steel and plenty of white overalls, not to mention hair nets.

In terms of “how are corn flakes manufactured”, there are many stages to the process, including:

  • Grain preparation
  • Dry Milling
  • Cooking
  • Cooling
  • Delumping
  • Drying
  • Cooling
  • Tempering
  • Flaking

Grain Preparation

The first step in how corn flakes are made is the arrival of the grain at the factory. There, it undergoes quality checks. Assuming it passes muster, the grain is sifted then cleaned to dispose of any fine or coarse materials as well as foreign materials like dust or stems. Various devices are used, including filter screens and gravity tables.

Next, the corn’s outer husk or “chaff” is removed by a process known as hulling. Most factories use an impact huller, a machine with a rotating centrifugal wheel to force the corn against an impact ring, removing the husk by force.

Dry Milling

Having been hulled, the corn is now further broken down to its components parts, separating the bran and germ from the kernel. What’s left is a chunk of corn flaking grits. It’s the corn grits that become corn flakes, with each grit making one flake.

First, the corn is mixed with water, a step known as tempering, bringing its moisture level to around 20-24% and causing different parts of the corn to harden and swell. This loosens the bonds between the parts of the corn, making them easy to break apart. This is done mechanically by force through a degerminator machine. The different components are then separated by a series of sieving, aspirating, gravity-separation and roller-milling processes.


To make corn flakes, the corn grits are mixed with a flavour solution. Whilst this solution will differ according to manufacturer, it’s generally made up of sugar, malt, salt, and water.

The flavouring and grits are carefully measured and loaded into the batch steam cooker, where they cook for around two hours at a pressure of around 15 to 18 pounds per square inch. They also rotate inside the cooker at a rate of between one and four rotations per minute, allowing for even mixing and cooking. In the end, the grits that entered the cooker as pale and brittle emerge golden and soft.


The cooked corn grits remain in the cooker for a time after cooking is complete, with the machine turned off and its vents open, allowing them to cool. Once cooled, they are emptied onto a conveyor belt under the cooker and resume their journey.


Some of the corn grits may have become stuck together during cooking. Delumping is essentially breaking up any clumps into single units. Cooling also continues at this stage.


The next step in the process of how cornflakes are produced in a factory involves the cooked and delumped corn grits being conveyed to the dryer, where the temperature and humidity are carefully controlled and the corn grits are dried without hardening them.

Cooling and Tempering

They are then cooled once more and then stored in an ambient environment for a time to allow their moisture levels to even out or “temper”.


Now comes the time for grits to become flakes. The grits pass between large metal rollers which flatten them out, ready for toasting.


The corn flakes toasting oven is sloped from the feed to discharge ends. This is to account for the way in which corn flakes are cooked. Rather than lay them out on a surface, flakes are suspended in a stream of hot air, somewhere between 275 and 330 degrees centigrade. The air flows from the base through perforated holes, just big enough so the air can pass without risking any flakes getting stuck. As for the slope in the oven, this maximises the flakes’ floating space.

How Are Corn Flakes Manufactured? Packaging

Kellogg's Corn Flakes packaging (Photo: NurPhoto via Getty Images)

Once cooked, the corn flakes are cooled ready to be packaged. They are funnelled through tubes and into their bags according to weight before the bags are sealed. Finally, they are boxed and placed on pallets, ready to go.

Explaining How Corn Flakes are Manufactured

Delicious! (Photo: MarkGillow viua Getty Images)

And that’s how corn flakes are made. From “how were corn flakes invented” to “how are corn flakes manufactured”, we’ve answered questions covering every key stage of cornflake production.


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