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Did you know that chocolate starts out as seeds inside a colorful fruit growing on a tree?
And those seeds taste bitter and sour?
With no sweetness at all?
What?
Hello friends and welcome back to Sleep Tight Science a bedtime show that answers your questions about science.
In this episode we're starting something new a series of topics called making and creating, where we explore how people make things, from raw materials all the way to the finished products you see, use and sometimes taste every day.
Tonight's topic was suggested by Amelia, who is five years old and from Indiana.
Thank you for your question, Amelia.
We are going to try and answer the following question.
How is chocolate made, from a tree all the way to the chocolate bar you unwrap?
We'll start with where chocolate begins cacao trees growing in tropical forests, colorful pods and the beans hidden inside.
Then we'll follow the transformation fermenting drying, roasting and grinding those beans into something that finally smells and tastes like chocolate.
Finally, we'll explore how chocolate makers turn that into dark chocolate, milk chocolate or white chocolate by adding different ingredients, and how they make it smooth, shiny and ready to snap.
Sounds yummy.
You don't have to remember every word.
Try to remember this.
Chocolate starts as bitter seeds inside a fruit, and making it involves fermentation, like bread rising roasting, like coffee beans, and careful mixing to get the flavor and texture just right.
Before we continue, here are some words to listen for.
Cacao, the tree and the raw beans that chocolate comes from.
Some people say cacao.
Some people say cacao.
Both are fine.
Cocoa, what we call it after processing, like cocoa powder or cocoa butter.
Fermentation, when tiny microorganisms create chemical changes that develop flavor.
Roasting, heating the beans to bring out deeper chocolate flavors.
Cocoa butter, the natural fat inside cacao beans that make chocolate smooth.
Tempering. heating and cooling chocolate carefully so it becomes shiny and snaps when you break it.
A quiet thank you to Anthony and Abram, eight-year-old twin boys from Waynesville, North Carolina, for introducing our show.
And to all our curious friends who send in questions.
You help us learn together.
Take a few deep belly breaths and picture this.
A tropical forest.
Small trees with colorful pods shaped like large eggs or small melons growing right on their trunks.
A farmer cuts one open.
Inside, white pulp and purple seeds.
Those seeds will travel far and change completely before they become the chocolate you know.
Ready to follow chocolate's journey from forest to factory?
Let's begin.
Chocolate comes from a tree called the cacao tree.
The scientific name is Thebroma cacao, which means food of the gods in Greek.
And once you taste chocolate, you might understand why ancient people thought it was divine.
Cacao trees grow in hot, humid regions near the equator.
West Africa, Central and South America, and Southeast Asia.
They're not tall trees, about as tall as a small house, maybe 5 to 8 meters or 15 to 25 feet.
They need shade from taller trees around them, lots of rain, and warm temperatures year-round.
Cacao trees are particular about where they live.
The fruit that grows on cacao trees is unusual.
Most fruits grow on branches, but cacao pods grow directly on the trunk and on thick branches stuck right to the bark.
The pods are shaped like large eggs, about the size of a small melon, with hard, thick shells you can't bite through.
They come in different colors when they ripen, yellow, orange, red, even deep purple.
It takes five to six months for a pod to ripen after the tree flowers.
If you cut open a ripe pod, inside you'll find 20 to 50 cacao beans seeds nestled in white sweet sticky pulp.
The pulp tastes tropical and fruity, almost like lychee or mango.
Some people eat it fresh or make juice from it.
But the beans themselves?
They're pale or purple.
And if you tried to eat one raw, you'd find it tastes bitter, astringent and nothing like chocolate.
Not yet.
Farmers harvest cacao pods by hands, using machetes or long poles with curved blades to reach the ones high up.
Each tree produces about 20 to 30 pods per year, and each pod holds enough beans to make about one or two chocolate bars.
It's careful, slow work.
Once the pods are harvested, farmers open them and scoop out the beans and pulp.
This is where the first big transformation begins.
Fermentation.
Beans and pulp are piled together in wooden boxes or under banana leaves and left to ferment for five to seven days.
Fermentation means tiny microorganisms.
Yeast and bacteria eat the sugars in the pulp, creating heat and chemical changes.
It's similar to how bread dough rises or how cucumbers turn into pickles.
During fermentation, the temperature inside the pile rises to about 49 degrees Celsius or 120 degrees Fahrenheit.
The beans turn from purple or pale to brown.
Chemical reactions start developing the flavors that will eventually become chocolate, and the sticky pulp liquefies and drains away.
Fermentation is the key transformation.
Without it, cacao beans stay bitter and astringent.
No chocolate flavor develops at all.
Different fermentation times and methods create different flavor profiles.
A farmer's skill in fermentation makes a huge difference in the final taste of the chocolate.
After fermentation, the beans are spread out to dry, usually in the sun, on big mats or wooden platforms, though some farms use special drying houses.
Drying takes about a week.
The moisture content drops from about 60% down to around 7%.
This prevents mold from growing and makes the beans stable enough to be shipped across the world.
Farmers turn the beans regularly so they dry evenly on all sides.
Once dried, The beans are sorted to remove any that are damaged or moldy, then packed into big burlap sacks, each one holding about 130 pounds of beans.
These sacks are shipped to chocolate makers around the world.
At this point the beans smell faintly chocolatey, but if you tasted one, It still wouldn't taste like the chocolate you know.
There's more work to do.
Now, let's take a moment to take a slow breath and use our imaginations for a moment.
Picture a tropical forest, warm and damp.
Small trees heavy with colorful pods growing right on their trunks.
A farmer cuts one open.
Inside, white pulp clings to purple seeds.
Those seeds are piled under leaves, warming, changing color, beginning their transformation.
Days later, they're spread on mats under the sun drying, waiting for the next step in their journey.
In the next part, we'll follow those beans to a chocolate factory, where roasting, grinding and careful mixing will finally turn them into chocolate.
Once beans arrive at a chocolate factory, the real transformation begins.
The first step is roasting.
Beans are loaded into large rotating ovens and roasted at temperatures between 120 and 175 degrees Celsius or 250 to 350 degrees Fahrenheit, for anywhere from 30 minutes to two hours.
This is just like roasting coffee beans or nuts.
The heat brings out deeper, richer flavors.
It makes the beans crunchy and loosens the thin papery shell around each bean.
Different roasting times and temperatures create different flavor notes.
Some chocolate tastes fruity, some nutty, some earthy.
And as the beans roast, the factory starts to smell like chocolate.
Next comes cracking and winnowing.
Roasted beans are cracked open and the thin outer shells are blown away by fans a process called winnowing, like blowing chaff off wheat.
What's left are cacao nibs, small dark pieces of the inside of the bean.
Nibs are what chocolate is made from.
You can actually buy cacao nibs in some stores.
They're crunchy, bitter, and intensely chocolatey.
Now the nibs are ground.
They're crushed between heavy steel rollers or stone mills over and over.
Grinding creates friction, and friction creates heat.
The heat melts the natural fat inside the nibs called cocoa butter.
About half of each bean is fat, so as the nibs are ground they turn from dry crumbs into a thick, dark flowing paste called chocolate liquor or cocoa mass.
It's liquid when it's warm and solid when it cools.
This paste is 100% cacao.
No sugar, no milk, nothing added yet.
It's bitter and intense.
At this point, chocolate can go two directions.
Direction one, cocoa powder.
If you press the chocolate liquor in a powerful hydraulic press, the cocoa butter or the fat squeezes out and can be collected separately.
What's left behind is a hard, dry cake of cocoa solids.
Grind that cake into powder and you get cocoa powder, the kind used for baking brownies or making hot chocolate.
Direction two, making chocolate bars.
Keep the chocolate liquor and start adding things to it.
What gets added depends on the type of chocolate you're making.
For dark chocolate, you add sugar and sometimes extra cocoa butter to make it smooth.
The percentage you see on dark chocolate bars, like 70 or 85, tell you how much of the bar is cacao.
The rest is mostly sugar.
Higher percentage means more cacao, less sugar, more intense flavor.
For milk chocolate, you add sugar, milk powder or condensed milk, and extra cocoa butter.
This makes it sweeter, creamier, and lighter in color than dark chocolate.
For white chocolate, there's no chocolate liquor at all.
Just cocoa butter, sugar, and milk powder.
That's why some people say white chocolate isn't real chocolate, because it doesn't contain any cocoa solids.
But it does use cocoa butter, so it still comes from the cacao bean.
Once the ingredients are mixed, the chocolate goes into a machine called a conch, where it's stirred and heated for hours, sometimes even days.
This smooths out the texture, evaporates unwanted moisture and acids, and develops the flavor.
Chocolate goes from gritty to silky smooth.
High-quality chocolate is conched longer.
Next is tempering. one of the trickiest steps.
Chocolate is carefully heated, cooled, and reheated to specific temperatures.
This aligns the cocoa butter crystals, so the finished chocolate will be shiny, smooth and snap cleanly when you break it.
Without tempering, chocolate can look dull, feel soft, or develop white streaks on the surface called bloom.
It's safe to eat, just not as pretty.
Professional chocolatiers practice tempering for years to get it just right.
Finally, the tempered chocolate is poured into molds, bars, shaped, chips, and cooled until solid.
Then it's wrapped, packaged, and ready to travel to stores.
From tree to bar can take weeks or even months, but the transformation is complete.
Close your eyes if you haven't already and use your imagination again.
See beans tumbling in a roaster, turning glossy and dark.
Grinding wheels turning cacao nibs into flowing liquid.
A conch stirring for hours, smoothing every particle.
Shiny, tempered chocolate pouring into molds, hardening into the exact shape you'll unwrap someday.
The next time you see chocolate or taste some as a treat, you might think about the long journey it took from a tree in a faraway forest, through fermentation and roasting and grinding, all the way to your hand.
Here's what you can notice about chocolate and how it's made.
Look at different kinds of chocolate side by side.
Compare dark chocolate, milk chocolate, and white chocolate.
Notice the color differences.
Dark brown, lighter brown, pale ivory.
Dark chocolate has the most cacao.
Milk chocolate has cacao plus milk and more sugar.
White chocolate has no cocoa solids at all, just cocoa butter, sugar, and milk.
Check the ingredient list.
It tells the story of what was added.
Dark chocolate usually lists cacao or chocolate liquor first.
Milk chocolate often lists sugar or milk first.
The order matters.
Ingredients are listed from most to least.
Taste the differences.
Dark chocolate tastes more bitter and intense.
Milk chocolate tastes sweeter and creamier.
White chocolate tastes sweet and milky with no chocolate bitterness at all.
The percentage on dark chocolate, 70% or 85%, tells you how much cacao versus sugar.
Higher percentage means stronger chocolate flavor.
Notice the snap.
Well-tempered chocolate snaps cleanly when you break it.
If it bends or crumbles, it wasn't tempered properly.
Still safe to eat, just a different texture.
The shiny surface comes from good tempering too.
Smell matters.
Chocolate makers talk about flavor notes the way people talk about coffee or wine.
Fruity, nutty, earthy, floral.
These flavors come from the beans themselves, how they were fermented and how they were roasted.
Cacao beans from different places taste different, just like apples from different orchards.
Did you know ancient Mayans and Aztecs drank cacao as a bitter, spicy beverage? no sugar.
Europeans added sugar and milk in the 1500s and 1600s, creating sweet chocolate.
Solid chocolate bars you can snap and eat weren't invented until the 1800s.
So back to Amelia's question.
Chocolate is made from cacao beans that grow inside pods on cacao trees.
The beans are fermented, dried, roasted, and ground into a paste.
Then sugar, milk, and cocoa butter are added depending on the type of chocolate.
The mixture is stirred smooth, tempered to make it shiny and snappy, poured into molds and cooled, transforming bitter seeds into the sweet chocolate many people love.
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Miles.
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And Wade, 3 years old, from Oley, Pennsylvania.
Danilo, 7 years old.
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In this episode, we learned how chocolate is made.
We discovered that chocolate comes from cacao trees that grow in tropical forests, with colorful pods growing right on the trunk.
We learned that inside each pod are 20 to 50 cacao beans covered in sweet pulp, and that the beans are fermented for about a week, a process that starts developing chocolate flavor.
We found out how beans are dried shipped roasted, cracked and ground into a thick paste, and how cocoa butter, the natural fat, is what makes chocolate smooth.
And we explored the differences between dark chocolate, mostly cacao and sugar, milk chocolate cacao, sugar and milk and white chocolate just cocoa butter, sugar and milk.
No cocoa solids at all.
Making chocolate is a long journey from seed to bar.
Take a slow, deep breath in and let it out gently.
Maybe tonight you'll dream of walking through a cacao forest, reaching up to touch a bright yellow pod growing on a tree trunk, opening it to find seeds nestled in sweet sticky pulp.
You might become a cacao bean yourself, resting under banana leaves as fermentation warms you, turning you from purple to brown.
Perhaps you'll ride a conveyor belt through a chocolate factory, tumbling into a roaster where heat and motion bring out deep, rich flavors.
You could flow as liquid chocolate through giant stone grinders, getting smoother and smoother with each pass, then pour into a shiny mold and harden into a perfect bar.
Maybe you'll shrink down and explore the crystals forming as chocolate is tempered tiny fat molecules lining up in perfect order, creating that beautiful snap and shine.
Or you might taste chocolate through time, starting with the bitter drink.
The Aztecs loved then watching as someone stirs in sugar for the first time, transforming it into something new.
Your imagination can take you anywhere from forest to factory.
Thank you for spending this time with us.
From Cheryl and Clark, good night, sleep tight.
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