CONCEPT 17: GOOD FRYING IS ALL ABOUT THE OIL TEMPERATURE Flashcards Preview

THE SCIENCE OF GOOD COOKING > CONCEPT 17: GOOD FRYING IS ALL ABOUT THE OIL TEMPERATURE > Flashcards

Flashcards in CONCEPT 17: GOOD FRYING IS ALL ABOUT THE OIL TEMPERATURE Deck (97):
1

What does frying all come down to?

Temperature of the oil.

2

Frying is usually held at what temp?

Between 325 and 375

3

Is hot oil boiling when you place food inside of it?

No, that's moisture escaping from the food.

4

What type of cooking method is utilized if frying?

Dry-heat cooking method.

5

What happens when you drop food in oil?

As steam flees the food, leaving tiny craters in its wake, a small amount of oil moves in to take its place. And, as the foo cooks, its outermost coating of starch dries out, becoming porous and crispy, with lots of oil clinging to the newly formed crust.

6

What happens if oil isn't hot enough?

Moisture won't turn to steam, the outer edge ill not dry out and trademark brown and crispy crust will not form.

7

Describe the end product when oil isn't hot enough.

Limp and soggy.

8

What happens when you dump copious amounts of food into oil?

Significantly lowers temperature.

9

A crisp crust is not only more flavorful but prevents what?

Fried food from tasting greasy.

10

What happens if fry oil gets too hot?

The food's exterior can burn before the interior cooks through. Even if it does cook through, excessive heat can cause excess moisture loss yielding tough food.

11

What is a secondary reason for the greasiness of fried food?

Oil absorption during frying.

12

Do most fried foods absorb oil after they're cooked?

Yes, this is when oil is able to penetrate the crust

13

By definition, what is fat or oil a solid at room temperature?

Fat is a solid and oil is a liquid.

14

What is fresh frying oil composed of?

98% triglycerides

15

What are triglycerides made of?

Three fatty acids chemically bonded to a molecule of glycerol.

16

What's the difference between triglycerides high in saturated and unsaturated fatty acids?

Triglycerides high in saturated fatty acids, such as those in meat, are solid at room temperature while those high in unsaturated fatty acids, like those in plants, are liquid.

17

What happens when fats and oils are heated, then put in contact with food? Why is this detrimental to fry oil?

The triglycerides can react with water from the food to form additional free fatty acids and glycerol, and unsaturated fatty acids can be oxidized by the air. Both these reactions limit the useful lifetime of frying oil by causing it to smoke at a lower and lower temperature.

18

What is smoke point? Is it the same with all oil?

Temperature at which oil begins to emit unwelcome smoke. Changes from oil to oil, depending on how quickly it breaks down to free fatty acids.

19

Regarding frying, what do the amount of free fatty acids in oil indicate?

The suitability of oil for high-temperature frying or, where the smoke point falls.

20

Does an oil's smoke point decrease with use?

Yes

21

What happens before, during and and after a potato hits hot oil?

Before hitting the oil, the potato hold moisture evenly spaced within. While frying in hot oil, the moisture turns to steam and exits, leaving holes in its wake. After, the craters on it's surface fill with oil, helping form a crisp brown crust.

22

What's the connection between water lost and oil absorbed?

The amount of oil absorbed is directly proportional to the amount of water lost.

23

TEST KITCHEN: Fries cooked at 275, 325 and 400.

275 were cooked through with soggy crust, 325 were perfect and 400 had a raw center with overcooked exterior.

24

Trick to give fries a mild, meaty flavor.

Add a few tablespoons of bacon fat before frying.

25

How do you create a shatteringly crisp crust with french fries?

Cover with a little cornstarch.

26

Two common characteristics of waxy potatoes.

High moisture, low starch.

27

Why are waxy potatoes bad for frying?

They contain so much moisture that large hulls of water evaporated inside the potato, leaving pools of oil.

28

Two common characteristics of starchy potatoes.

High starch, low moisture.

29

What does the high starch content of a Russet do when fried? Why is this good?

Starch granules on the outer layers swell and explode, releasing a starch molecule called amylose that turns into an excellent crust.

30

Is it important to rinse your starchy potatoes before frying?

Yes

31

Technique for rinsing starchy potatoes.

Rinse under cold running water until clear.

32

Why is rinsing important?

When potatoes are fried, any excess sugars left on the surface will brown too quickly during the first stage of frying; rinsing removes the sugars.

33

Hot or cold potato before frying? Why?

Refrigerating them in a bowl of ice water for at least 30 minutes means that potatoes will be nearly frozen when entering the hot oil. This allows a slow, thorough cooking of the inner potato and a finished batch with a crispier crust.

34

What does leaving the skin on prevent?

The little airy blisters that people love in their fries.

35

Why does cornstarch help crisp french fries?

A thin layer helps remove surface moisture and creates a gel-like coating that releases amylose.

36

What two fats make great fries?

Lard and shortening.

37

Regarding time, why fry around 350 instead of 400?

Lower temperatures allow for easier monitoring and won't get away from the cook.

38

How do you add a high flavor not when frying with peanut oil?

Add a tablespoon of bacon fat per quart.

39

Why should you rest fries between the par-fry and final fry?

After 10 minutes of rest the exterior starches form a thin film. This helps the potatoes to become crisp once they are fried again.

40

Why par-fry?

Release rich and earthy flavors of russet potatoes.

41

Who is Russ Parsons?

Food writer.

42

What are Russ Parson's five stages of fry oil?

Break-in (too fresh to fry well), fresh, optimum, degrading (on the was to spoiling) and runaway (dark, smelly, and prone to smoking).

43

What's the secret for used fry oil?

Save a cup and mix it with fresh. The fried food will be more crisp and golden.

44

Why is oil better for frying as it's used?

As oil is continuously exposed to heat it breaks down, producing slippery, soap like compounds that can penetrate the water barrier.

45

Why shouldn't you fry with fresh oil?

Fresh oil can't penetrate the barrier of moisture that surrounds food.

46

Why does mixing old and fresh oil work?

During repeated use free fatty acid increases from about 0.03 to 0.05% in fresh oil and 8 to 10 % in runaway oil.

47

A practical way to filter oil.

Coffee filter.

48

What ratio of new to old should be used?

1 cup old to 5 cups new.

49

Should you use the same oil to fry all foods?

No, discard oil for seafood; multiple batched of chicken or potatoes may be cooked in the same oil, but oil used for doughnuts should only be for doughnuts.

50

Should oil be kept clean while frying?

Yes, skim away any detritus and keep salt and/or water out.

51

What is detritus?

The remains of something that has been destroyed or broken up.

52

Should you use oil once reaching it's smoke point?

No, it will transfer off flavors to food.

53

What is happening during smoke point?

The high temperature begins to break oil down to glycerol and free fatty acids, producing a bluish smoke.

54

What is glycerol further broken down into during smoke point?

Acrolein which is a component of smoke.

55

What is acrolein?

The simplest unsaturated aldehyde. It is a colorless liquid with a piercing, disagreeable, acrid smell.

56

What causes smoke to become so irritating?

The presence of acrolein causes smoke to be extremely irritating to eyes and throat.

57

Do smoke points vary between oils?

Yes, depending on origin and refinement.

58

What's the relation between free fatty acids and smoke point?

Smoke point tends to increase as free fatty acid content decreases and degree of refinement increases.

59

What is flash point?

The point at which vapors from the oil can first ignite when mixed with air.

60

What is the Joël Robuchon was of cooking lower-starch potatoes?

Start the fries and oil cold. As the oil gradually heats the potatoes interior cooks through until reaching the high temperatures that create a crisp and golden crust.

61

Why would the Robuchon way not work for higher starch potatoes?

Too many starch granules were burst, leading to an overly thick and leathery crust.

62

What is one benefit when frying yukon gold potatoes?

The skin is so thin you don't need to remove it.

63

Why don't you need to rinse the Yukon potatoes using Robuchon method?

A low-starch potato contains less sugars (which come from the breakdown of starch) on the surface to brown, and the lower fry temperatures also slow down growing more than they do crisping - fries won't over-brown.

64

Stir or don't stir in Robuchon method?

Not string for the first 20 minutes will allow enough of a crust to form; they won't stick. Touching the tender spuds too early will make them break apart.

65

What size fries are less prone to stick?

1/4-inch fries

66

Why should you keep used frying oil in freezer?

Cold temperatures slow oxidation and help prevent rancidity; better for long term (beyond a month).

67

Can you store oil in the cupboard?

A cool, dark cupboard is good for short term, since exposure to air and light hastens oil's rate of oxidative rancidification and the creation of off flavors and odors.

68

TEST KITCHEN: OIL IN CUPBOARD, REFRIGERATOR AND FREEZER FOR TWO MONTHS.

Sautéed bread tasted fishy with cupboard, not much better with refrigerator and freezer kept it remarkably clean.

69

Why is putting oil in the freezer so effective?

Though the absence of light is important, very cold temperatures are the most effective at slowing oxidation and the production of peroxides.

70

What are the source of rancid oil's unpleasant taste and smell?

Peroxides

71

What is the classic method of frying?

Double-dip, par-cooking and final fry.

72

Two ways fries absorb oil.

As potatoes cook, they lose moisture near their surface, which is replaced by oil. As they cool, oil from the exterior gets pulled in.

73

Why does the Robuchon method absorb less fat than classic?

Less moisture is lost because of lower temperatures and there's no resting period to account for.

74

Difference in fat between Robuchon (cold start) and classical.

13% fat (JR) and 20% fat (classical).

75

What is Sriracha made from?

Garlic and chiles.

76

How do you stop shrimp from curling when fried?

After cleaning, put shrimp on it's back and make two 1/4-inch slices an inch apart.

77

What does flower form when mixed with water?

Gluten

78

Does cornstarch form gluten?

No

79

What temperature should tempura be fried at?

400 degrees Fahrenheit

80

What happens when under-mixing tempura batter?

Batter will be too thin and not provide a proper barrier for shrimp against the hot oil.

81

What happens when over-mixing tempura batter?

You wind of with a coating so thick it would be more at home on a corn dog.

82

Why didn't using only flour in a tempura batter work?

The flour and water form gluten, giving it a nice structure; however, this can make it thick and doughy.

83

Why didn't using only cornstarch work for tempura batter?

Created a styrofoam-like texture.

84

What kind of water slows down the development of gluten?

Ice water--until it warms up.

85

What substitute for water creates a delicate and lacy batter?

Seltzer water

86

Why does seltzer water impede the formation of gluten?

With a pH of 4, it's slightly more acidic than regular tap water, enough to slow down the formation of gluten.

87

What pH is ideal for gluten development?

Ph of 5 to 6 is optimal for gluten formation.

88

What other ingredient, besides seltzer water, can help impede gluten formation?

Vodka

89

Tempura batter recipe.

1 1/2 C AP flour
1/2 C cornstarch
1 C vodka
1 large egg
1 cup seltzer water
Kosher salt

90

When should you make tempura batter? Why?

Because gluten develops even without stirring, a batter left sitting will thicken with every second that passes.

91

What happens to the batches of cooked shrimp if you only use seltzer water?

The coating becomes progressively thick and greasier over time.

92

What is present in the flour that forms gluten?

Protein

93

Percentage of water and alcohol in vodka.

60% water and 40% alcohol.

94

Why does vodka help prevent gluten?

Alcohol does not combine with protein to form gluten.

95

Besides ingredients, what mistakes cause a batter to form too much gluten?

Over-mixing and long rest periods.

96

What makes batter fluid and keeps gluten formation in check no matter how much you stir?

Alcohol!

97

What happened when eggs whites were whipped into the tempura batter?

Creates a balloon like coating; it's too puffy.

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