EXAM 1: Heat Transfer Flashcards
What is heat transfer
How energy is transferred from the source (gas, electric, wood, charcoal) to the food
What is radiation
The direct transmission of energy in the form of electromagnetic (non-ionizing) waves
What is an example of radiation cooking
Microwaves
How do microwaves cook food
Magnetron converts electricity to short non-ionizing waves
915 or 2450 megahertz (2.45 Gigahertz)
Waves cycle on and off
Hot and cold spots
Factors that affect how microwaves cook foods
Distribution of water
- water evenly distributed = even cooking
Size and shape of food
Presence of salt
- NaCl ions make microwaves energy less available to food
What is the heat transfer method that uses electromagnetism to transfer heat to a neighboring material
Induction
What pans work for inductions
Only cast iron or those made with stainless steel that is magnetic
What is a benefit of induction
Lessens hot spots
What is the heat transfer method that is the transfer of thermal energy from one molecule to another molecule
Conduction
Examples of conduction
Heat in the metal of a pan/pot to the liquid in the pan or food in contact with the pan
Heat in the metal of a grill to the food in contact with the grill
Heat in the liquid to the food in contact with the liquid
Heat on the outside of a food moving to the inside of the food
What is the heat transfer method that is the heating and movement of current of hot air or liquid (water/oil)
Convection
What are examples of convection
Oven, simmering/boiling, steaming, deep frying
What is air frying
Air fryers don’t fry food
Use convection to rapidly circulate hot air to cook food at high temperature
Outside becomes crispy - like frying
Convection toaster oven are also “air fryers”
What is temperature
Gives a measure of the intensity of the movement of molecules
Cooking is the process of…
Transferring energy from a heat source to food
- alters molecular interactions and speeds up chemical reactions and speeds chemical reactions
What does cooking do
Foods become more palatable
Preserve food, kills bacteria/pathogens
It is irreversible
What does temperature tell us
How hot or cold something is
What is the temperature of freezing point (F)
32 degrees F
What temperature does the Maillard reaction can occur
140 degrees F
What temperature range does egg proteins fully coagulate
160 degrees F to 180 degrees F
What temperature is the boiling of water
212 degrees F
What temperature range does carmelization occur
230 degrees F
What are factors to consider when selecting pots and pans
Affordability
Durability
Material type
Maintenance
Intended purpose
What are the two ways that a material of a pot and pan affects how it performs
Ability to distribute heat evenly through the material
- conductivity
Ability to retain heat and transfer it efficiently to food
What are the most commonly used pot/pan materials
Stainless steel
Aluminum
Copper
Cast iron
Mixed metals
Non-stick: Teflon and Greblon
What are the characteristics of stainless steel
Conduction: poor
Heat retention: short
Low maintenance
No reaction with acidic foods
Uses: heating water, serving dishes and storage
What are the characteristics of plain aluminum
Plain aluminum
- conduction: excellent
- heat retention: short
- less durable: dents easily
- reacts with strong acids
- uses: utensils, heating water
What are the characteristics of anodized aluminum
Anodized aluminum
- conduction: moderate to excellent
- retention: medium
- more durable, harder metal, low maintenance
- resistant to strong acids
- uses: pan searing, sautéing, stir-frying/pan-fry, sauces/glazes
What is dry heat preparation
A method of cooking in which heat is transferred by air, radiation, fat or metal
What are examples of dry heat methods
Baking, roasting, broiling, grilling, barbecuing and frying
*higher temperatures are reached as the moist methods can only get to boiling temperatures
What is moist heat preparation
A method of cooking in which heat is transferred by water, any water-based liquid, or steam
What are types of moist-heat preparation
Scalding, poaching, simmering, stewing, braising, boiling, steaming
What is the heating method that incorporates both dry heat and moist heat
Microwaving
Uses radiation that is aimed at the water in the food or beverage
What is poaching
Water heated to a temperature of 160 to 180 degrees F, somewhat hotter than scalding
The food is either partially or totally immersed
Relatively motionless bubbles appear on the bottom of the pan but the water has not yet reached the point of actually bubbling
Used for delicate foods
What is simmering
Water simmers at just below boiling point, never less than 180 degrees F
Gently rising bubbles that barely break the surface
Preferred over boiling sometimes because it is more gentle and will usually not damage or overcook the food as easily
What is boiling
The water must reach 212 F
The difference is the bubbles
What is blanching
To dip a food briefly into boiling water
