THE SCIENCE OF HEAT AND COLD

Question 1

How did discovering fire help our ancestors?

Answer 1

Protection from predators and cooking food. We no longer spent the day grinding through plant matter. Now humanoid ancestors could use extra time to explore, build and hunt - be human.

Question 2

How did cooking help higher brain function?

Answer 2

Cooking made it easier to digest high-quality proteins, especially meat; therefore the link between the advent of fire and human brain development.

Question 3

What is heat?

Answer 3

A form of energy. Term describes the speed of molecules in a substance such as air or water. The higher the temperature the faster the molecules are moving and the more energy, or heat, the molecules contain.

Question 4

How is heat transferred molecularly?

Answer 4

Fast-moving molecules bump into slower-moving ones, causing them to pick up speed.

Question 5

What wide range of changes can occur when molecules in food speed up?

Answer 5

Food can change color, lose moisture and their integrity (more tender).

Question 6

Most common forms of heat in cooking

Answer 6

Conduction, convection and radiation.

Question 7

Does heat always makes food taste better?

Answer 7

No, it can spoil the taste of food; oils oxidize and bitter substances are released.

Question 8

Sauté

Answer 8

Cook foods in a thin film of hot fat in a skillet or hot burner.

Question 9

Sautéing work best for what foods?

Answer 9

Flat, relatively thin foods, such as steaks, chops, and cutlets, as well as small items, such as chopped vegetables, shrimp or scallops.

Question 10

Roast

Answer 10

Cook foods in a pan in a hot oven.

Question 11

Roasting works best with what foods?

Answer 11

A wide range of foods from large cuts of meat and whole birds to sliced potatoes.

Question 12

Fry

Answer 12

To cook in a significant quantity of hot oil in a skillet or pot set on a hot burner.

Question 13

Frying works best for what foods?

Answer 13

Many of the foods that are best for sautéing can also be fried; many fried foods are breaded or battered.

Question 14

Shallow-frying or pan-frying

Answer 14

Food can be partially submerged in oil. Generally employs a skillet and a modest amount of oil (about 1 cup).

Question 15

Deep-frying

Answer 15

Food can be completely submerged in oil. Requires use of a large pot and 1 to 2 quarts of oil.

Question 16

Boil

Answer 16

Cook foods in boiling liquid in a pot set on a hot burner.

Question 17

Boiling works best with what foods?

Answer 17

Best with pasta, grains and vegetables.

Question 18

Is the temperature of boiling water constant?

Answer 18

No, water boils at 212ºF around sea level. The boiling drops 2 degrees for every 500-foot increase in elevation. No matter the temperature, when a liquid boils, large bubbles energetically break the surface of the liquid at a rapid and constant pace.

Question 19

Why does the boiling point of water change depending on atmospheric pressure?

Answer 19

Additional pressure translates as increased resistance in the air to the release of liquid molecules turned into gas, thus requiring more energy to complete the reaction.

Question 20

Simmer

Answer 20

To cook foods in liquid that is just below the boiling point in a pot set on a hot burner.

Question 21

What is another term for simmer?

Answer 21

Gentle boil

Question 22

What is the temperature range for simmering?

Answer 22

180 to 205 degrees. When a liquid simmers, small bubbles break the surfaces at a variable and infrequent rate.

Question 23

What foods are best for simmering?

Answer 23

Many grains, including rice, are best simmered; it’s usually reserved for tougher cuts or foods that need longer to cook. Simmering is invaluable for stocks, soups and sauces.

Question 24

Poach

Answer 24

To cook foods in a liquid that is well below the boiling point in a covered pot set on a stovetop. Related to simmering; the temp of the liquid is lower (no bubbles are breaking the surface) and the pot is generally covered to create a constant, gentle cooking environment.

Question 25

Temperature of poaching water.

Answer 25

160 to 180 degrees.

Question 26

What foods are best for poaching?

Answer 26

Usually delicate foods like eggs, fish, fruit and some organ meats.

Question 27

Steam

Answer 27

An especially delicate method cooking foods that are suspended, generally in a basket, over simmering liquid in a covered pot set on a burner.

Question 28

Best foods for steaming?

Answer 28

Steaming is an excellent choice for vegetables, fish and delicate foods like dumplings.

Question 29

Correlation between steam and flavor.

Answer 29

Unlike other moist-heat cooking methods, steaming does not wash away flavor.

Question 30

Braise

Answer 30

To cook food by first sautéing them and then adding liquid, covering the pan, and simmering.

Question 31

Best foods for braising?

Answer 31

Ideal for tough cuts that require prolonged cooking to become tender, such as pot roast.

Question 32

Stew

Answer 32

This is a subset of braising; food is sautéd, then simmered

Question 33

Foods best for stewing.

Answer 33

Generally reserved for recipes that involve small chunks of food, not entire roasts.

Question 34

Grill

Answer 34

To cook foods an a grate set over fire.

Question 35

Best foods for grilling.

Answer 35

Although the term “grilling” is often used to describe the preparation of any food cooked over fire, we generally reserve it for foods that cook quickly, such as steaks, cutlets, chops, vegetables and seafood.

Question 36

Grill-Roast

Answer 36

To cook foods on a grate set over a modest fire confined to a portion of the grill in a closed environment.

Question 37

Foods best for grill-roasting.

Answer 37

Best for thick, large cuts that require substantial cooking over moderate heat, such as a whole chicken or roast.

Question 38

How is grill-roasting similar to roasting?

Answer 38

When a lid is placed on a grill, the cooking method resembles roasting, especially if the food is not positioned directly over the fire and thus won’t brown too quickly.

Question 39

Barbecue

Answer 39

To cook foods on a grate set over a small, smoky fire confined to a portion of the grill in a closed environment.

Question 40

Foods best for barbecuing.

Answer 40

Best for tough cuts that require prolonged cooking to become tender.

Question 41

Difference between grill-roasting and barbecuing.

Answer 41

When barbecuing, the setup is the same as with grill-roasting but the fire is smaller and wood is used to create a smoky flavor in the food.

Question 42

Temperatures below 40ºF can inhibit what in peaches?

Answer 42

Certain enzymes that normally break down pectin in its cell walls during the ripening process.

Question 43

What do temperatures below 40 degrees do to bacteria?

Answer 43

Suppresses their activity.

Question 44

What is the “danger zone” for bacterial growth?

Answer 44

40 to 140 degrees.

Question 45

Moisture of food begins to freeze at what temp?

Answer 45

32 degrees, and whether the moisture is in fruit, ice cream, or meat, it will form crystals.

Question 46

What happens to frozen fruits and vegetables when thawed?

Answer 46

Ice crystals that formed will rupture cells walls and internal cell organelles in fresh foods, like fruits and vegetables, which release enzymes from their locked compartments. When thawed, these enzymes cause produce to develop off-flavors and turn brown and soggy.

Question 47

In frozen vegetables, how can enzymes that produce off-flavors be halted?

Answer 47

Blanching. This is how manufacturers keep vegetables from turning to mush or tasting sulfuric when frozen and thawed.

Question 48

How do manufacturers reduce crystals size of frozen fruits?

Answer 48

Since fruit cannot withstand precooking manufacturers generally add sugar to reduce crystal size and thus limit the damage.

Question 49

What acid do manufacturers use to deactivates the enzymes that causes browning?

Answer 49

Ascorbic acid.

Question 50

What is the biggest issue with freezing meat and other protein?

Answer 50

Moisture loss

Question 51

How do proteins lose moisture due to freezing?

Answer 51

The ice crystals damage the cell structure and, as a result, frozen meat loses more moisture when cooked than meat that was never frozen. In addition, freezing causes moisture loss due to surface dehydration.

Question 52

TEST KITCHEN: fresh and frozen ground beef, 7oz each. How much moisture was lost?

Answer 52

When cooked, the fresh lost 3/4 teaspoon of water compared to 2 teaspoons in the frozen.

Question 53

What is freezer burn?

Answer 53

Ice crystals that encrust the surface of food. Caused by the ravages of constant freezing, thawing, and refreezing.

Question 54

Does your freezer stay a constant temp?

Answer 54

No, constant opening and closing causes foods to continually heat up and cool down which accelerates the damage of ice crystals.

Question 55

Why are ice cubes rock hard and ice cream soft and scoopable?

Answer 55

Sugar (or and substance that dissolves in water) affects the freezing point of water. The more sugar added, the lower the freezing point.