4.2.1 The Science of Cooking

To Intro to Culinary Arts

Agenda for Day 10

●Today’s Lesson 2.1.1 - NEW UNIT!

○The Science of Cooking

○Caramelization, Coagulation, etc… :)

●While we wait…

○1) Connect to Quizizz
2) In the chat, share with us whether you prefer
A) Cooking
B) Baking
C) Idk
D) I like it all!

2.1.1

Cooking!

It’s Magic!

Heat

Transfer

What is it??

What is Heat Transfer?

Heat transfer is an exchange of thermal
energy between two objects.

The rate of heat transfer depends upon the temperatures of each entity and the medium through which the thermal energy is being transferred.

In cooking, heat transfer refers to heating your food items through a cooking appliance, such as a stove, fryer, microwave, or oven.

3 types of Heat Transfer

Match

Pre-test:

Math the types of heat transfer to their description.

• The process of heat being transferred between objects through direct contact.

• Combines heat transfer to circulation to force molecules in the air to move from warmer area to cooler ones

• The process where heat and light waves strike and penetrate the food.

Conduction

Convection

Radiation

• Conduction

• Convection

• Radiation

3 Types of Energy Transfer

Conduction

●Process of heat being transferred between objects
through direct contact, and it's the most common type of heat transfer

●For example, the burners on the stove will conduct heat energy to the bottom of a pan sitting on top of it. From there, the pan conducts heat to its contents.

●Deep fryer: hot oil cooks the food when it comes into
direct contact with it

●Conduction is the slowest method of heat transfer, but the direct contact between the cooking surface and the item to be heated allows food to be cooked from the outside in

Conduction heat is responsible for
moving heat from the outside of
the food to the inside.

3 Types of Energy Transfer

Convection

●Combines heat transfer and circulation to force molecules in the air to move from warmer areas to cooler ones

●As the molecules closest to the heat source become warm, they rise and are replaced by cooler molecules (think of a fan circulating!)

●Two types:

○Natural Convection: When molecules at the bottom of a cooking vessel rise and warm while cooler and heavier molecules sink (creates a circulating current that evenly distributes heat throughout the substance being prepared)

○Mechanical Convection: Outside forces circulate heat, which shortens
cooking times and cooks food more evenly (like when you stir liquid in a pot, or when a convection oven uses a fan and exhaust system to blow hot air over and around the food)

Convection

Mechanical

Natural

3 Types of Energy Transfer

Radiation

●Process where heat and light waves strike and penetrate your food

●NO direct contact between the heat source and the cooking food

●Two Types:

○Infrared Radiation

■Electric or ceramic heating element that gives off electromagnetic energy
waves

■Waves travel in any direction at the speed of light to quickly heat food, and
are mainly absorbed at the surface of whatever you are preparing.

■Examples: glowing coals in a fire, toaster ovens, and broilers.

○Microwave Radiation

■Short, high-frequency waves that penetrate food, which agitates its water
molecules to create friction and transfer heat

■Microwave heat transfer usually cooks food faster than infrared radiation, as it is able to penetrate foods several inches deep.

■Microwave radiation works best when cooking small batches of food

●

Radiation

Infrared

Microwave

Match

Check for understanding:

Math the types of heat transfer to their description.

• The process of heat being transferred between objects through direct contact.

• Combines heat transfer to circulation to force molecules in the air to move from warmer area to cooler ones

• The process where heat and light waves strike and penetrate the food.

Conduction

Convection

Radiation

• Conduction

• Convection

• Radiation

Heat vs. Temperature

Heat refers to the amount of energy in an object.  Temperature refers to the intensity of heat.  Temperature is the measure of heat. 

If you add heat to something, its temperature goes up.  If you reduce the temperature, you are taking its heat away. 

When is Food Ready to Eat?

​When it is safe and the target temperature in the center regardless of how thick, how much it weighs, or what temperature it is cooked at.

• The best way to tell - with an accurate digital thermometer
  
  

• Each type of protein has its own recommended internal temperature
  
  

• Carryover cooking

 Your meat will continue to cook even after it has been removed from the heat source.  For about 15 minutes after you remove the meat, the exterior temperature of the item releases its heat in 2 directions, so the meat's interior gets warmer and the outside grows cooler.  Generally, the meat will increase in internal temperature by about 5 degrees after removing it from the heat source.

Some Cooking Theory…

Thickness is More Important
than Weight

The temperature of your food
moves slowly upward during
cooking, but the thickness of
the meat is a major factor in
how long it takes to get the
center to the desired
temperature.

A thin steak cooks faster than
a thick steak.

Poll

Sometimes people use other, less reliable methods to check for the doneness of meat. Which ones have you heard of?

• Finger test method: If it feels like the soft part of your hand, it's raw.

• Juices run clear: If the juices run clear, the meat is done.

• Meat has shrunk: If the meat shrunk, it's close to being done.

Debunk the Myths!

This method suggests that meat cooked to different degrees of doneness feels like different parts of your hand.

Concern: The obvious concern with this method is that everyone’s hands and fingers feel different, as do different cuts of meat depending on the species, animal maturity, fat content, etc. In addition to getting your fingers burned as you’re feeling the meat this is not a reliable way to determine meat safety or degree of doneness.

This method suggests that meat is safe to eat once the juices run clear.

Concern: Color change is not an effective indicator of doneness. Internal meat color and the color of meat juices are subject to factors such as pH and fat content. Research by the USDA revealed that 1 in 4 hamburgers turn brown without reaching the safe internal temperature of 160°F. 

This method suggests that if the meat starts to look smaller then it’s close to done and if it’s substantially smaller than when you started it may be overcooked.

Concern: The degree that which a meat product will shrink is variable and depends on factors such as the lean-to-fat ratio and the cooking method. This, like other visual methods, will not consistently indicate safety or level of doneness.

Finger Test

Method

Juices Run

Clear

Meat Has
Shrunk

Multiple Choice

Check for understanding: What happens to the meat's internal temperature after it has been removed from the heat source?

• It decreases slightly.

• It stays the same.

• It increases by about 5 degrees.

• It becomes colder.

Multiple Choice

Check for understanding: Which method is a reliable way to determine meat safety or degree of doneness?

• Use an internal thermometer

• Juices run clear

• Determine how much the meat has shrunk

• Finger-test method

How Heat Affects Food

Sugars

Proteins

Starches

Water

Coagulation

Gelatinization

Caramelization

Evaporation

04

02

03

01

Fats
Melting

05

Proteins: Coagulation

Plant- and animal-based foods are made
up of long molecules called proteins. When
they’re heated, the proteins break up and
lose moisture. This makes them change
from a liquid (or semi-liquid) to a solid in
a process called coagulation in food.

Coagulation starts at 140°F

Examples: hard-boiled or fried eggs

Starches: Gelatinization

When starches are heated, they absorb liquids around them. This makes solid starchy foods softer. Starches can also be added to foods like soups and stews that are mostly liquid for thickening purposes.

The whole process is known as
gelatinization.

Gelatinization starts at 150°F

Examples: pasta and rice getting larger
and softer after boiling, flour thickening
a soup

Sugars: Caramelization

Heated sugar tends to turn brown and change
flavor. This not only applies to the sugar we
actively add to foods, like baked goods or
desserts but to the naturally-occurring sugars in
foods, as well. This process, known as
caramelization, is responsible for the majority
of flavors we associate with cooking. Since this
happens at a higher temperature than water
boiling, it also explains why foods only brown if
prepared with dry heat methods.

Caramelization starts at: 338°F

Examples: brown top of a creme brulee, bread
turning brown as it bakes

Water: Evaporation

This is the process most people are
probably familiar with from science class.
When water is heated, the molecules move
faster and faster until they turn into a gas
(steam) and evaporate. Because water is in
so many foods, this explains why foods
get more dried out the longer they’re
cooked.

Water boils at 212°F

Examples: water boiling, spinach losing
shape

Fats: Melting

Unlike water, fats won’t evaporate when
heated, though they do melt. At room
temperature, they can be solid, liquid, or
somewhere in between, but all of them become
liquid when heat is applied to them. Because it
takes much higher temperatures to burn foods
that fit in this category, they’re often used as a
medium to cook foods, rather than just as an
ingredient.

The temperature this starts at varies
depending on the fat

Examples: using butter or oil to pan-fry

Multiple Choice

Check for understanding: What process is responsible for the browning and change in flavor of sugars when heated?

• Carmelization

• Condensation

• Evaporation

• Gelatinization

Multiple Choice

Check for understanding: What process is responsible for breaking down proteins resulting in liquids become solids? Hint: Fried egg

• Carmelization

• Coagulation

• Evaporation

• Gelatinization

Whoa!

That was a lot of information. What questions do you have?

What’s Next?

Next Lesson:

2.1.2 - Dry Heat Cooking Methods

Friday, 9/27