Popcorn Science 101

The Kernel

All You Need To Know About Popcorn!

There is nothing like the smell of freshly popped popcorn! Popcorn can make your movie night extra special or can be turned into a healthy, scrumptious snack. 

But what is it about popcorn that makes it irresistible?

This article is the “all-you-need to know” about popcorn. In the following sections, we will give you all the information you need to become a popcorn expert – from its scientific name and different varieties to its history. Don’t forget to check out the corny facts section (pun intended!) at the end!

What Is Popcorn?

Popcorn (Zea Mays Everta) is one of the six types of corn, which also include dent corn, pod corn, flour corn, sweet corn, and flint corn. Popcorn is especially notorious for its ability to POP when heated. It’s the only one of the six corn kernels that can. 

Popcorn is considered a cereal grain, and at one time was consumed as a common breakfast cereal. It has now transformed into a delicious salty or sweet snack. 

Popcorn kernels are made of three layers:

  1. Outer shell (known as the bran, hull, or pericarp) – protects the kernel from environmental factors.
  2. Endosperm – the middle layer that stores starch and water to feed the germ.
  3. Germ – is the seed embryo.

It’s the water in the endosperm and the outer shell or “hull” that makes popcorn so magical, but we will get to the science of the pop in a minute.

History of Popcorn

Popcorn was first sold in movie theaters almost 100 years ago, but its history starts long before the delicious yellow, buttery popcorn was enjoyed at the movies. According to research by Mexico’s Institute of Anthropology and History, corn started out in southwestern Mexico thousands of years prior as wild grass. Evidence even suggests that corn was popped as early as 4,700 B.C. Recent fossil samples were collected from different parts of China indicating that popcorn was popping there around the same time too! 

Interestingly though, when corn started out as a wild grass, the part that holds the kernels, what we call “the cob”, was only about 2 inches long with a measly few kernels. When cooked to create popcorn, they resembled a small batch of crunchy popcorn. Not anything like the overflowing bowl of soft, popped kernels we know today.

The light and fluffy popcorn we know and love today have been transformed through modern processing and cultivating techniques to ensure the best popcorn is produced. 

(the evolution of maize from only containing a few kernels to the hybrid corn we have today.)

While early American settlers were exposed to corn, including popcorn, the real magic didn’t begin to happen until the late 1800s and early 1900s. The invention of the steel plow in the mid-1800s transformed American agriculture as corn became an important cash crop, nicknamed “prairie gold”. 

In 1875, Frederick J. Myers patented a corn-popping device that added a stay-cool handle. Then as popcorn started to become a well-loved treat, the portable popcorn machine, made in 1885 by Charles Cretors became a popular way for entrepreneurs to satisfy that craving. This was also the time when commercial popcorn brands were also starting, Iowa’s Dickinson Co. sold kernels under the brand names Big Buster and Little Buster.

Heading into the early 1900s, popcorn popping machines were designed where you could easily add butter, salt, or sugar. Each transformation aimed to refine the popcorn process as vendors followed the street fairs, festivals, and crowds to pop up more profits. 

An Ole’ Timey Wimey Popcorn Cart

The Popcorn Movie Takeover

Between 1920 and 1930, Hollywood forever transformed popcorn. This was the time when over 20,000 movie theaters opened up across the country. Originally theaters banned snacks and beverages to keep the theaters clean, but heading into the late 1920s this began to change. 

As the Great Depression began to hit in the 1930s, popcorn transformed into a go-to affordable snack of choice starting at 10 cents per bag. This is when movie theaters began to allow popcorn vendors into the theaters to help the businesses stay afloat during hard times. 

Popcorn is still helping to prop up the profitability of the big screen. Theaters sell their popcorn between an 800% to 1,500% mark-up to beef up the slim margins on ticket sales. 

(1950’s movie theatre concession stand)

Microwave Popcorn Enters the Home

Before the microwave, people could get popcorn at the movies, the circus, or any other well-attended event, or they could cook it on the stove – which wasn’t quite the same as that delicious, buttery theater popcorn. 

Then came along self-taught scientist, Percy Spencer, who fell in love with the power of microwave technology. In 1946, Raytheon – Percy’s company – created the microwave oven. Popcorn was the test subject for many of his original experiments. 

The microwave did not become a common household appliance until the 1980s. With the rise in televisions in the home, popcorn sales began to drop as people were watching movies from the comfort of their homes. 

That is until 1981! The year that the first microwaveable popcorn was released, patented by General Mills. People could pop their very own popcorn snack. Since it contained perishable butter, it was actually required to be refrigerated – unlike the shelf-stable versions today. 

Popcorn Today

Shelf-stable popcorn hit the stores in 1984 creating a multimillion-dollar industry.

Popcorn has since become a dominant treat in the food market! Traditional options of salt and butter are still the most popular. The sweet tooth of Americans has driven up the sales of chocolate and cheese popcorn. 

Different types of popcorn 

With the variety of popcorn, there is popcorn for all of your needs. Each kernel contains a variety of characteristics that make each one unique. 

Let’s look at the different types of popcorn kernels!

There are three main types of popcorn kernels:

  • Mushroom – This kernel turns into a fluffy, ball-shaped popcorn. Mushroom popcorn is sturdier, larger, and more dense than other types of popcorn. Its shape makes it the best popcorn to cover in chocolate or caramel. 
  • Butterfly – Also known as snowflake, this popcorn is known for the wing-like shape that forms. Due to the shape, it holds onto butter and seasonings making it the type that you would buy at the movie theaters. 
  • Ladyfinger – This popcorn is the dainty one of the popcorn world . It is typically relatively small in size, making it great for toppings on desserts, salads, and soups. Ladyfinger popcorn is also tender and has a thin hull. A thin hull makes it a perfect option for people with braces or sensitive teeth.

The four colors of popcorn kernels are:

  • Yellow popcorn: this is the most popular type of popcorn and tends to have a nutty flavor.
  • White popcorn: runner up to the yellow popcorn, this is a great option for a neutral, plain flavor.
  • Red popcorn: the kernels are red, but they pop small and white.
  • Blue popcorn: these are comparable to the red popcorn but blue. 

Then you have the magic of hulless popcorn. Truth be told, there is actually no such thing as a true hulless popcorn. We learned earlier that the hull is an essential part of the magic of popcorn. However, some kernels do have smaller hulls or hulls that divide into smaller pieces when they pop. This makes them less noticeable and less likely to get stuck in between your teeth. Hulless popcorn is a great option for those with braces. 

Common kernels that you can get in smaller, hulless forms are called baby whites, baby yellow, Ladyfinger, and red kernels.

Varieties of Popcorn 

The food industry has really honed into the popcorn market. There are so many varieties, flavors, and textures of popcorn on the market, each with its own unique yet delicious twist. 

The more common popcorn varieties are:

  • Classic salted popcorn – can’t go wrong with a classic.
  • Classic sweet popcorn – a light snack to curb that sweet tooth.

Then we can get into gourmet popcorn varieties such as:

Whatever your choice of flavor, there is popcorn made for it

From Seed to Table

The Midwest is responsible for the majority of the popcorn grown and sold worldwide – also known as the Corn Belt of the United States. The Corn Belt includes Illinois, Indiana, Iowa, Kentucky, Michigan, Missouri, Nebraska, and Ohio. 

The U.S. reserves over 96,000,000 acres per year just for corn production, but only a small portion of that is dedicated to popcorn. (Most of the US corn crop is grown to feed livestock, make ethanol fuel for cars, and to make high fructose corn syrup for sodas and junk food!)

Planting the Seed

Popcorn seeds are bred to contain traits to optimize production and product. So genetic traits such as stalk strength, grain color, and even successful popping are taken into consideration. 

Plant breeders ensure that the best seeds are made by inbreeding. Inbreeding plants means taking the pollen from the male flower and using that pollen to fertilize a female flower of the same plant. This ensures that the seeds produced are the most desirable popcorn seeds. 

The process of inbreeding is how modern agriculture has transformed corn from being a 1 to 2 inches stalk to being upwards of 7 to 8 inches. Also, different stands of popcorn are designed for specific purposes. Certain types are used for microwavable popcorn and others are designed to be caramelized.

In the spring, farmers will plant each popcorn seed about 1 ½ inch into the soil and about 6 inches apart. That is approximately 28,000 seeds per acre! The popcorn seeds will begin to emerge from the soil in about 10 days. With a combination of the sun, water, carbon dioxide, and nutrient-rich soil the popcorn plant will begin to create sugar to fuel the popcorn plant’s growth (also known as photosynthesis).

The popcorn plant will grow to be about 8 feet tall with green leaves and will eventually begin to produce ears of corn. The ears of corn will be protected by a green husk. Each ear of corn will have a feathery-like tassel at the top of the plant that will produce yellowish-powdered pollen. Then the ears of corn will produce long strands of silk that will catch the pollen. This process is called pollination and will allow the ears of corn to produce kernels. 

Once pollination occurs, the popcorn plant and kernels will continue to mature until the plant turns dry and brown. 

Time for Harvest

Once the popcorn plant stalks are brown and the kernels have dried and become hard it’s time to HARVEST! Farmer performs tests to try to harvest popcorn when the kernels contain about 16% to 20% moisture. This moisture level is still too moist for popping, but that’s ok, the kernels have a bit more drying to do.. 

Popcorn is commonly harvested in bulk by the cob using a large combine. This combine is called a “corn head”. The corn head combine is able to strip each ear of corn directly off the stalk. Then the kernels are shelled from the cob and the cob is sent to the back of the machine to be transported for other use. 

The kernels can then be stored in large containers called silos for 1 to 3 months, and sometimes up to 12 months. It is crucial for the farmers to use proper storage and preservation practices to ensure the kernels stay dry and safe from things such as rodents or weather. 

Can you guess what type of corn this is?

Popcorn Processing 

Once the kernels are ready to be packaged and are dried at the optimum moisture level of  13.5%-14%, then they are transported for final processing. This process typically involves using a screen and a vibrator to separate any additional debris from the kernels, and thorough cleaning. 

The kernels are now ready for packaging. Packaging of kernels commonly includes microwaved popcorn, large bags, jars, or bulk distribution to popcorn companies. 

To The Table

Finally, popcorn can be enjoyed! Americans consume over 13 billion quarts of popcorn a year. It has turned into one of the greatest snacks there is. Popcorn is so versatile, it can be transformed into a savory treat or sweet treat, or even a healthy snack. There is a type of popcorn for everyone. 

The Science Behind the Pop!

Not all types of corn have the ability to pop like popcorn. The kernel of popcorn contains a small amount of water stored within the endosperm. This is exactly why farmers must harvest the corn at a specific level of moisture within the kernel. 

When the kernel is placed under heat, the water begins to expand and build pressure against the hull. Once the pressure gets too great, the hull gives way, causing the popcorn to POP! The optimal temperature for a pop is about 180 degrees Celsius (355 degrees Fahrenheit).

Due to the high temperature, the starch that is contained in the endosperm begins to gelatinize and expand. This is what gives popcorn the white-yellow color and foamy texture. 

If a popcorn fails to pop, this could mean that the hull was faulty or there was not enough moisture in the kernel. Without moisture, there is no way for steam to form and create pressure for the pop. Another way for the popcorn to fail is improper heating. Popcorn needs fast and even heating with either air or oil. 

Check out this awesome ultra slow-motion video of popping popcorn!

Popcorn Cooking Methods

Long before kitchen appliances brought the cooking fire into the house, popcorn was popped over a fire in a pot. Each time a new way to heat up food has emerged, a way to use it for popcorn has quickly followed!

While there is no “best” way to pop the popcorn, here are some the common methods:

Popcorn Nutrition 

Popcorn is the perfect healthy snack! Can you make it higher in calories, sugars, and fats? Absolutely! Popcorn is a whole grain that when popped by itself contains no additional additives or ingredients (unless purchased pre-popped or microwave popcorn). 

Air-popped popcorn only contains 30 calories per cup! The addition of a hint of oil or butter only increases that to about 80 calories per cup. Compared to other American favorites such as potato chips that are much high in fat and calories, popcorn is a great alternative. 

Popcorn also contains fiber. Dietary fiber comes from whole grains, beans, legumes, fruits, and vegetables. Dietary fiber has been shown to reduce cholesterol levels and lower the risk of cardiovascular disease, obesity, diabetes, and different types of cancers (i.e. colon cancer).

Nutrition experts recommend consuming 21-38g of fiber per day. The average American only consumes 16g of fiber per day. You can easily boost your fiber intake with a daily snack of popcorn. Since popcorn has fiber and is a whole grain, it is slow digesting to help keep you full for longer. 

Popcorn also contains a wide variety of essential nutrients such as magnesium, phosphorus, and iron. 

The nutrition facts of a three-cup serving of air-popped, unbuttered, and unsalted popcorn:

  • Calories: 94 calories
  • Protein: 3g
  • Fat: 1.1g
  • Carbohydrate: 18.6g
  • Fiber: 3.6g
  • Sugar: 0.2g
  • Calcium: 1.8 mg
  • Iron: 0.9mg (3% of the RDI)
  • Magnesium: 35.0mg (9% of the RDI)
  • Phosphorus: 85.8mg (9% of the RDI)
  • Potassium: 78.9mg (3% of the RDI)
  • Sodium: 1.8mg 
  • Cholesterol: 0.0mg

*The RDI is the Recommended Daily Intake 

To prevent adding too many additional calories and fat, stick to lightly buttered or oil. Also, keep it fun by adding flavor from your favorite seasonings!

Final Thoughts

Who knew popcorn could be so interesting! Even though it’s been around for a while now (about 5,000 years), the cinema industry helped transform popcorn into what it is today. 

What do you think about popcorn? Whether you are a teacher, parent, or popcorn fan, share this information with your class, friends, or family to appreciate the journey of the popcorn. 

Popcorn Facts

  • January 19th is National Popcorn Day
  • Popcorn can pop up to 3 feet
  • Due to the sugar shortage during WWII, Americans consumed 3x more popcorn
  • Those little, crunchie pieces of unpopped popcorn at the bottom of the bag are called old maids
  • In the 1800s, popcorn was consumed with milk and sugar like you would cereal
  • Popcorn is a whole grain and gluten-free
  • Nebraska produces about 250 million points of popcorn per year
  • Popcorn is the official snack of Illinois
  • A successful piece of popcorn is 20 to 50 times bigger than the kernel

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