The chemistry of cookies - Stephanie Warren

Summary

This script takes viewers on a scientific journey through the baking of cookies, highlighting the chemical reactions that transform dough into a delicious treat. From the melting of butter at 92°F to the Maillard reactions at 310°F, each stage is a testament to the mad science of baking. The script explains how butter's water turns to steam, proteins from eggs coagulate, and sugars caramelize, all contributing to the cookie's texture and flavor. It ends with a sensory tip: when the nutty, toasty aromas fill the air, your cookies are ready to enjoy with a glass of milk.

Takeaways

• 🍪 The transformation of dough into cookies is a series of chemical reactions triggered by heat.
• 🧈 At 92°F, butter in the dough melts, causing the dough to spread and its water content to turn into steam.
• 🥚 Pasteurization occurs around 136°F, killing bacteria like salmonella in the eggs.
• 🔗 At 144°F, proteins in the eggs begin to denature, helping to solidify the dough's structure.
• 💧 Water boils at 212°F, causing the cookie to dry out and form a crispy texture.
• 🌬️ Baking soda acts as a leavening agent, creating carbon dioxide gas and making the cookie light and flaky.
• 🏿 The Maillard reaction at 310°F gives cookies their brown color and contributes to their flavor and aroma.
• 🍬 Caramelization starts at 356°F, adding the sweet, nutty, and slightly bitter flavors characteristic of caramel.
• 🕒 The oven temperature affects the extent of caramelization and Maillard reactions, influencing the cookie's final color and taste.
• 👃 Your sense of smell can be a reliable indicator of when cookies are done, detecting the aromas of the Maillard and caramelization reactions.

Q & A

What happens to the dough when it reaches 92 degrees Fahrenheit?

The butter inside the dough melts, causing the dough to start spreading out.

Why does the dough spread out when the butter melts?

As the butter melts, its trapped water is released, and as the cookie gets hotter, the water expands into steam, pushing against the dough from the inside.

At what temperature do salmonella bacteria typically die off in the dough?

Salmonella bacteria die off when the dough reaches 136 degrees Fahrenheit.

What changes occur in the proteins of the eggs at 144 degrees Fahrenheit?

At 144 degrees Fahrenheit, the proteins in the eggs start to unfold and get tangled up with their neighbors, forming a linked structure that gives substance to the dough.

How does the water content in the cookie affect its texture as it bakes?

As water boils away at 212 degrees Fahrenheit, the cookie dries out and stiffens, with steam leaving behind airy pockets that make the cookie light and flaky.

What role does sodium bicarbonate play in the baking process of cookies?

Sodium bicarbonate, or baking soda, reacts with acids in the dough to create carbon dioxide gas, which forms airy pockets in the cookie.

What is the Maillard reaction and at what temperature does it occur?

The Maillard reaction is a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor. It occurs at around 310 degrees Fahrenheit.

How do Maillard reactions affect the color and flavor of cookies?

Maillard reactions produce a range of flavor and aroma compounds, which also react with each other, forming more complex tastes and smells, and give foods a rich brown color.

What is caramelization and at what temperature does it start in cookies?

Caramelization is the process where sugar molecules break down under high heat, forming sweet, nutty, and slightly bitter flavor compounds. It starts at 356 degrees Fahrenheit in cookies.

Why might someone set their oven to 310 degrees if they want barely browned cookies?

Setting the oven to 310 degrees Fahrenheit will prevent caramelization, which starts at 356 degrees, resulting in cookies that are barely browned.

How can one determine when cookies are ready without a timer?

One can rely on the smell of the nutty, toasty aromas produced by the Maillard reaction and caramelization as an indication that the cookies are ready.

Outlines

00:00

🍪 The Science of Baking Cookies

This paragraph delves into the transformative process of baking cookies, comparing it to a scientific experiment. As the dough bakes, it undergoes a series of chemical reactions that change its structure and appearance. The butter in the dough melts at 92 degrees Fahrenheit, causing the dough to spread as water is released and turns into steam. This steam pushes against the dough, creating the initial rise. At 136 degrees, any salmonella bacteria present in the eggs are killed, ensuring safety. As the temperature reaches 144 degrees, the proteins in the eggs begin to change, contributing to the dough's solidity. The water in the dough boils away at 212 degrees, leading to the cookie's drying and stiffening. The leavening agent, baking soda, reacts with acids to produce carbon dioxide, creating the cookie's characteristic light and flaky texture. The Maillard reaction at 310 degrees gives the cookie its brown color and complex flavors, while caramelization, which starts at 356 degrees, adds the sweet and nutty flavors associated with caramel.

Keywords

💡Time-lapse video

A time-lapse video is a cinematic technique where time is compressed, allowing viewers to see events unfold at a much faster pace than real-time. In the context of the video, it is used to depict the rapid transformation of cookie dough into a finished cookie, emphasizing the dramatic changes that occur during baking.

💡Chemical reactions

Chemical reactions involve the transformation of substances into new materials through the rearrangement of atoms. The video script describes how the process of baking a cookie is essentially a series of chemical reactions that change dough into a delicious treat. This concept is central to the video's theme of baking as a scientific process.

💡Emulsion

An emulsion is a mixture of two liquids that are normally immiscible, such as oil and water, which are combined with the help of an emulsifying agent. In the script, butter is described as an emulsion, highlighting its role in the baking process where it helps to create a smooth texture in the dough and releases water as it melts.

💡Salmonella

Salmonella is a type of bacteria that can cause foodborne illness. The video script mentions that eggs, a common ingredient in cookie dough, may contain salmonella. However, the high temperatures in baking are sufficient to kill these bacteria, ensuring the safety of the final product.

💡Proteins

Proteins are large biomolecules composed of amino acids and are essential for the structure, function, and regulation of the body's cells, tissues, and organs. In the context of the video, proteins from eggs in the dough unfold and interact with heat, leading to the solidification of the dough and contributing to the cookie's texture.

💡Maillard reaction

The Maillard reaction is a chemical reaction between amino acids and reducing sugars that gives browned food its distinctive flavor. Named after French chemist Louis-Camille Maillard who first described it in the 1910s, this reaction is highlighted in the video as the process that gives cookies their rich brown color and complex flavors.

💡Caramelization

Caramelization is the process by which sugars, particularly sucrose, break down and change color when heated. This process is described in the video as the source of the sweet, nutty, and slightly bitter flavors found in caramel and cookies, and it occurs at higher temperatures than the Maillard reaction.

💡Sodium bicarbonate

Sodium bicarbonate, commonly known as baking soda, is a leavening agent used in baking. It reacts with acids to produce carbon dioxide gas, which helps cookies rise and creates a light, airy texture. The video script explains how this chemical is crucial in the baking process, contributing to the final structure of the cookie.

💡Temperature

Temperature is a measure of the average kinetic energy of the particles in a substance and plays a critical role in the baking process. The video script outlines specific temperatures at which different reactions occur, such as the melting of butter, the death of salmonella bacteria, and the Maillard and caramelization reactions, emphasizing the importance of temperature control in baking.

💡Texture

Texture refers to the feel and appearance of a food's surface or inside. In the video, the transformation of dough into a cookie with a specific texture is described, including the creation of peaks and craters, and the development of a crispy or soft mouthfeel, which are all influenced by the chemical reactions that occur during baking.

Highlights

A time-lapse video of a cookie baking resembles a monster coming alive.

Bakers are likened to mad scientists due to the chemical reactions involved in baking.

At 92 degrees Fahrenheit, butter in the dough melts, causing the dough to spread.

Butter is an emulsion of water, fat, and dairy solids that help hold them together.

Melting butter releases trapped water, which expands into steam, causing the cookie to rise.

Salmonella bacteria, which can infect eggs, are killed at 136 degrees Fahrenheit.

At 144 degrees, proteins in the eggs begin to change, contributing to the dough's structure.

Proteins in eggs unfold and tangle with heat, solidifying the dough.

Water boils away at 212 degrees, drying out and stiffening the cookie.

Steam inside the cookie leaves behind airy pockets, contributing to its light and flaky texture.

Sodium bicarbonate, or baking soda, reacts with acids to create carbon dioxide gas, aiding in leavening.

Maillard reactions occur at 310 degrees, giving foods a rich brown color and complex flavors.

Caramelization, the breakdown of sugar molecules, begins at 356 degrees, defining caramel's flavor.

Caramelization continues up to 390 degrees, influencing the cookie's final color and taste.

The aroma of the Maillard reaction and caramelization can signal when cookies are ready, without a timer.

Science plays a crucial role in the delightful process of baking cookies.

Transcripts

In a time-lapse video, it looks like a monster coming alive.

For a moment, it sits there innocuously.

Then, ripples move across its surface.

It bulges outwards, bursting with weird boils.

It triples in volume.

Its color darkens ominously, and its surface hardens

into an alien topography of peaks and craters.

Then, the kitchen timer dings.

Your cookie is ready.

What happened inside that oven?

Don't let the apron deceive you!

Bakers are mad scientists.

When you slide the pan into the oven,

you're setting off a series of chemical reactions

that transform one substance, dough, into another, cookies.

When the dough reaches 92 degrees Fahrenheit,

the butter inside melts,

causing the dough to start spreading out.

Butter is an emulsion,

or mixture of two substances

that don't want to stay together,

in this case, water and fat,

along with some dairy solids that help hold them together.

As the butter melts, its trapped water is released.

And as the cookie gets hotter, the water expands into steam.

It pushes against the dough from the inside,

trying to escape through the cookie walls

like Ridley Scott's chest-bursting alien.

Your eggs may have been home to squirming salmonella bacteria.

An estimated 142,000 Americans are infected this way each year.

Though salmonella can live for weeks outside a living body

and even survive freezing,

136 degrees is too hot for them.

When your dough reaches that temperature, they die off.

You'll live to test your fate with a bite of raw dough

you sneak from your next batch.

At 144 degrees, changes begin in the proteins,

which come mostly from the eggs in your dough.

Eggs are composed of dozens of different kinds of proteins,

each sensitive to a different temperature.

In an egg fresh from the hen,

these proteins look like coiled up balls of string.

When they're exposed to heat energy,

the protein strings unfold and get tangled up with their neighbors.

This linked structure

makes the runny egg nearly solid,

giving substance to squishy dough.

Water boils away at 212 degrees,

so like mud baking in the sun,

your cookie gets dried out and it stiffens.

Cracks spread across its surface.

The steam that was bubbling inside evaporates,

leaving behind airy pockets that make the cookie light and flaky.

Helping this along is your leavening agent,

sodium bicarbonate,

or baking soda.

The sodium bicarbonate reacts with acids in the dough

to create carbon dioxide gas, which makes airy pockets in your cookie.

Now, it's nearly ready for a refreshing dunk

in a cool glass of milk.

One of science's tastiest reactions

occurs at 310 degrees.

This is the temperature for Maillard reactions.

Maillard reactions result

when proteins and sugars break down and rearrange themselves,

forming ring-like structures,

which reflect light in a way

that gives foods like Thanksgiving turkey

and hamburgers

their distinctive, rich brown color.

As this reaction occurs,

it produces a range of flavor and aroma compounds,

which also react with each other,

forming even more complex tastes and smells.

Caramelization is the last reaction

to take place inside your cookie.

Caramelization is what happens

when sugar molecules break down under high heat,

forming the sweet, nutty,

and slightly bitter flavor compounds that define, well, caramel.

And, in fact, if your recipe calls for a 350 degree oven,

it'll never happen,

since caramelization starts at 356 degrees.

If your ideal cookie is barely browned,

like a Northeasterner on a beach vacation,

you could have set your oven to 310 degrees.

If you like your cookies to have a nice tan,

crank up the heat.

Caramelization continues up to 390 degrees.

And here's another trick:

you don't need that kitchen timer;

your nose is a sensitive scientific instrument.

When you smell the nutty, toasty aromas

of the Maillard reaction and caramelization,

your cookies are ready.

Grab your glass of milk,

put your feet up,

and reflect that science can be pretty sweet.