Ch.12: Sugars, Chocolate, and Confectionery

Chapter 12 of the book "On Food and Cooking: The Science and Lore of the Kitchen" by Harold McGee (1984) The History of Sugars and Confectionery The Nature of Sugars Honey Tree Syrups: Maple, Birch, Palm Table Sugar: Cane and Beet Corn, Glucose, Fructose, Malt Syrups Sugar Candies and Confectionery Setting the Sugar Concentration Cooling and Crystallization Kinds of Candies Chewing Gum Candy Storage and Spoilage Chocolate The History of Chocolate Making Chocolate The Special Qualities of Chocolate The Kinds of Chocolate Chocolate and Cocoa as Ingredients Tempered Chocolate Chocolate and Health

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Part of Public › Books › On Food and Cooking (Harold McGee) · 16 courses

1. [Sugars, Chocolate, and Confectionery] Why do all humans share an innate liking for sweetness?

   Sweetness is the taste of sugars, the energy source that fuels all life. We first taste it in mother's milk.McGee: "Sugar is pure sensation, crystallized pleasure."

2. [Sugars, Chocolate, and Confectionery] What does sugar do to the gluten network of baked goods and the egg-protein network of custards?

   Sugar makes both networks more tender. Sugar molecules get in the way of the proteins bonding to each other, so the proteins coagulate less.

3. [Sugars, Chocolate, and Confectionery] What does heating sugar until its molecules break apart produce?

   Brown color and a more complex flavor: acidity, bitterness and a rich aroma besides sweetness. This is caramelization.

4. [Sugars, Chocolate, and Confectionery] In molecular terms, how is chocolate the opposite of sugar?

   Sugar is one kind of molecule; chocolate is a mixture of hundreds of kinds of molecules. Sugar is purified out of plant juices. Chocolate's molecules are created by fermenting and roasting a seed that is bland on its own.Chocolate has one of the most complex flavors we know, yet it lacks sweetness, which sugar supplies.

5. [The History of Sugars and Confectionery] Before sugar was made, what was the most concentrated natural source of sweetness?

   Honey. Example: dates, among the sweetest fruits, approach 60% sugar; honey reaches 80%.

6. [The History of Sugars and Confectionery] For how long have humans collected honey?

   For at least 10,000 years. A rock painting in the Spider Cave of Valencia, Spain (about 8000 BCE) shows people raiding a wild beehive.

7. [The History of Sugars and Confectionery] What does the word manna mean today?

   A sugar-rich liquid that certain trees and certain insects secrete. Example: in the Middle East, Bedouins collect several pounds of manna from tamarisk trees in a morning.

8. [The History of Sugars and Confectionery] The sugar alcohol mannitol is named after manna, the sugary secretion of some trees, from which it was first extracted.

9. [The History of Sugars and Confectionery] In what sense is honey making the model for all human sugar production?

   Both start from a sweet plant juice and remove its water to concentrate the sugars. Example: sources of sweet juice include palm trees, maple and birch trees, agave, maize stalks and sugar cane.

10. [The History of Sugars and Confectionery] What kind of plant is sugar cane (Saccharum officinarum)?

    A grass up to 20 feet tall whose juice is about 15% sucrose.

11. [The History of Sugars and Confectionery] Where and when was sugar first made from cane?

    In India, before 500 BCE. The juice was pressed out of the cane and boiled down to a dark mass of crystals coated with syrup (raw sugar, called gur).

12. [The History of Sugars and Confectionery] How were the first refined white sugars made?

    By washing the dark syrup coating off raw cane sugar crystals. Indian medical texts describe them, a couple of centuries after 350 BCE.

13. [The History of Sugars and Confectionery] Where do the English words sugar and candy come from?

    From Sanskrit, through Arabic. Sugar comes from sharkara ("gravel, small chunks"), candy from khandakah ("sugar").The words follow the route of sugar from India through the Middle East to Europe.

14. [The History of Sugars and Confectionery] How did medieval Europeans first use sugar?

    As a spice and a medicine. Europeans met sugar during the 11th-century Crusades; Venice then became the hub of the sugar trade.Example: lozenges, pastilles and comfits survive from medieval medicinal sweets.

15. [The History of Sugars and Confectionery] What were the original confections in medieval Europe?

    Medicinal sweets made by apothecaries (druggists). The word comes from Latin conficere, "to put together, to prepare".

16. [The History of Sugars and Confectionery] What medicinal purposes did sugar serve in medieval Europe?

    Taste Its sweetness covered the bitterness of drugs. Vehicle Being meltable and sticky, it mixed and carried other ingredients. Slow release A solid fused mass of sugar released its medicine gradually. Balance of the body Sugar was thought to encourage heat and moisture, balancing other foods and aiding digestion.

17. [The History of Sugars and Confectionery] What do the candy maker's stages "thread", "soft ball" and "hard crack" describe?

    How concentrated a boiling sugar syrup is. Each stage suits particular candies. Confectioners developed such stages in the 17th century.

18. [The History of Sugars and Confectionery] What made cheap candy available to everyone in the 19th century?

    Sugar from beets, and machines that automated cooking, pulling and shaping sugar. The control of crystallization was refined in the same century.

19. [The History of Sugars and Confectionery] What is fondant?

    The basic material of fudge and of all creamy or semisoft candy centers. It was developed around 1850; the name is French for "melting". Most candy today is a variation on bonbons, taffy or fondant.

20. [The History of Sugars and Confectionery] What role did sugar play in the Atlantic slave trade?

    Sugar plantations were probably the trade's main driver. By one estimate, they used the forced labor of two-thirds of all 20 million Africans enslaved in the Americas.Columbus brought cane to Hispaniola in 1493; West Indian plantations supplied the 18th-century boom in European consumption.

21. [The History of Sugars and Confectionery] Is sugar from beets chemically different from sugar from cane?

    No: both are the same pure sucrose. The Prussian chemist Andreas Marggraf first got beet-sugar crystals identical to cane sugar in 1747. The beet industry took off from 1812 under Napoleon, who wanted France independent of sugar from the English colonies.

22. [The History of Sugars and Confectionery] How fast did world sugar production grow between 1900 and 1964?

    It increased sevenfold, faster than any other major crop in history.

23. [The Nature of Sugars] Which kinds of atoms are sugars made of?

    Carbon, hydrogen and oxygen, with the carbon atoms forming the backbone. Example: glucose is C6H12O6\mathrm{C_6H_{12}O_6}C6​H12​O6​ .

24. [The Nature of Sugars] What is the difference between a monosaccharide and a disaccharide?

    A monosaccharide is a simple sugar; a disaccharide is two simple sugars joined together. Example: glucose and fructose are monosaccharides; sucrose (glucose + fructose) is a disaccharide.

25. [The Nature of Sugars] What are the two primary uses of sugars in living things?

    Storing chemical energy, and building physical structures. Example: cellulose, hemicellulose and pectin in plant cell walls are long chains of sugars.

26. [The Nature of Sugars] Which chemical property of sugars matters most in the kitchen?

    Sugars attract water strongly: they dissolve easily and bond firmly, though temporarily, to the water molecules around them.

27. [The Nature of Sugars] Sugars dissolve readily in water and bond strongly to nearby water molecules.What uses does this give sugar in foods?

    Moist baked goods Sugar holds moisture in them. Soft frozen desserts Sugar keeps them from freezing into a solid block of ice. Binding A sticky sugar matrix holds particles together. Example: marzipan, granola bars. Glazes Sugar keeps them moist and glossy. Preserving fruit Sugar draws water out of spoilage microbes, which stops their growth.

28. [The Nature of Sugars] What role does glucose (also called dextrose) play in living cells?

    It is the sugar from which cells most commonly get their energy directly. In fruits and honey glucose is always mixed with other sugars.

29. [The Nature of Sugars] Starch is a chain of glucose molecules.

30. [The Nature of Sugars] In which kitchen ingredient do cooks most often meet pure glucose as the sweetener?

    Corn syrup. Corn syrup is made by breaking starch down into single glucose molecules and short glucose chains.

31. [The Nature of Sugars] A chain of two glucose molecules is called maltose.

    Example: corn syrup consists mainly of glucose and maltose.

32. [The Nature of Sugars] How does glucose compare with table sugar (sucrose) in the kitchen?

    Glucose is less sweet, dissolves less, and gives a thinner syrup.

33. [The Nature of Sugars] At about what temperature does glucose melt and begin to caramelize?

    About 150°C (300°F).

34. [The Nature of Sugars] How are glucose and fructose related chemically?

    They have the same chemical formula, C6H12O6\mathrm{C_6H_{12}O_6}C6​H12​O6​ , but different structures. Glucose, sucrose and fructose; dots are carbon atoms. Glucose is a six-corner ring, fructose here a five-corner ring.

35. [The Nature of Sugars] What are the distinctive properties of fructose (levulose) among the common sugars?

    It is the sweetest and most soluble, holds water best, and caramelizes at the lowest temperature. Fructose caramelizes at about 105°C (220°F).Example: 4 parts of fructose dissolve in 1 part of room-temperature water (sucrose: 2 parts).

36. [The Nature of Sugars] Why does fructose raise blood glucose more slowly than glucose or sucrose?

    The liver must first convert fructose before the body can use it for energy. For this reason McGee calls fructose preferable for diabetics.

37. [The Nature of Sugars] Why does fructose taste much less sweet in hot drinks than in cold ones?

    Heat changes fructose molecules from their sweetest shape into less sweet shapes. The sweetest shape is a six-corner ring; heat turns it into five-corner rings.The six-corner ring dominates in cold, slightly acid solutions.At 60°C (140°F) its apparent sweetness is cut nearly in half. Glucose and sucrose change much less.

38. [The Nature of Sugars] Fructose is sweetest in its six-corner ring form, which dominates in cold, slightly acid solutions; when hot it turns into less sweet five-corner rings.In what kind of drink is fructose a useful substitute for table sugar?

    In cold drinks: half as much fructose gives the same sweetness, saving nearly 50% of the calories. In hot coffee fructose is only as sweet as table sugar.

39. [The Nature of Sugars] What is sucrose made of?

    One glucose and one fructose joined together. Sucrose is table sugar. When glucose and fructose bond to form it, a molecule of water is released.

40. [The Nature of Sugars] From which plants do we obtain sucrose?

    Sugar cane (from its stalks) and sugar beets (from their storage roots). All green plants make sucrose in photosynthesis.

41. [The Nature of Sugars] What combination of properties makes sucrose the most useful common sugar?

    It is very sweet and soluble, makes the thickest syrups, and stays pleasant when very concentrated. Among the common sugars, sucrose is second to fructose in sweetness and solubility.Example: in candies and preserves other sugars can taste harsh at the same concentration.Example: 2 parts sucrose dissolve in 1 part of room-temperature water.

42. [The Nature of Sugars] At what temperatures does sucrose melt and caramelize?

    Melts around 160°C (320°F), caramelizes around 170°C (340°F).

43. [The Nature of Sugars] What is invert sugar?

    The mixture of glucose and fructose obtained by splitting sucrose. The splitting is called inversion. "Inversion" refers to a change in optical properties: sucrose and the mixture of its parts rotate polarized light differently.

44. [The Nature of Sugars] How do cooks and manufacturers split sucrose into glucose and fructose?

    By heating a sucrose solution with a little acid, or with enzymes.

45. [The Nature of Sugars] What does an invert syrup consist of?

    About 75% glucose and fructose, and 25% sucrose.

46. [The Nature of Sugars] Why can invert sugar be sold only as a syrup, not as crystals?

    Its fructose cannot crystallize completely while glucose and sucrose are mixed in.

47. [The Nature of Sugars] Why are invert sugars useful in candy making?

    They limit the crystallization of sucrose.

48. [The Nature of Sugars] What is lactose made of?

    Glucose and galactose. Lactose is the sugar of milk.

49. [The Nature of Sugars] Why do food manufacturers use lactose?

    For bulk: it is much less sweet than table sugar. Example: sweetness of lactose 40, sucrose 100.

50. [The Nature of Sugars] Besides tasting sweet, what effects does sweetness have on the flavor of food?

    It masks or balances sourness and bitterness, and makes aromas seem stronger. The aroma boost may happen because sweetness tells the brain that the food supplies plenty of energy.

51. [The Nature of Sugars] How does the time course of sweetness differ between sucrose, fructose and corn syrup?

    Sucrose Slow to be detected; the sweetness lingers. Fructose Registers quickly and strongly, and fades quickly. Corn syrup Its sweetness appears slowly, reaches only about half of sucrose's peak, and lasts longer than sucrose's. Because fructose fades quickly, fruitiness, tartness and spiciness come through without leftover sweetness covering them.

52. [The Nature of Sugars] Rank fructose, sucrose, glucose, maltose and lactose by sweetness, with sucrose = 100.

    Fructose 120 > sucrose 100 > glucose 70 > maltose 45 > lactose 40.

53. [The Nature of Sugars] How sweet are corn syrup, high-fructose corn syrup and invert sugar syrup, with sucrose = 100?

    Corn syrup 30 to 50, high-fructose corn syrup 80 to 90, invert syrup 95. Corn syrup is glucose and maltose; in high-fructose corn syrup, enzymes have converted part of the glucose to fructose.

54. [The Nature of Sugars] Why are sugars more robust kitchen materials than proteins, fats or starch?

    Sugars are small, stable molecules: they mix easily with water and survive boiling. By contrast, proteins coagulate, fats go rancid and starch chains break apart.McGee: "Sugars are wonderfully robust materials!"

55. [The Nature of Sugars] What happens to sugar molecules in a sufficiently concentrated solution?

    They bond to each other and form pure solid crystals.

56. [The Nature of Sugars] What two things does the crystallization of sugar make possible?

    Getting pure sugar out of plant juices, and making many kinds of candy.

57. [The Nature of Sugars] What is caramelization?

    The set of chemical reactions that occur when a sugar is heated until its molecules begin to break apart. Example: colorless, odorless, sweet sucrose crystals become hundreds of new compounds.

58. [The Nature of Sugars] What kinds of compounds does caramelization produce?

    Small fragments that are sour, bitter or strongly aromatic, and large flavorless molecules that are deep brown. Longer cooking leaves less sugar and sweetness and makes the caramel darker and more bitter.

59. [The Nature of Sugars] What happens to sucrose molecules first when table sugar is caramelized?

    They split into glucose and fructose, which then fragment and recombine into new molecules.

60. [The Nature of Sugars] Glucose and fructose are reducing sugars: they have reactive atoms that donate electrons to other molecules (the opposite of oxidation).

61. [The Nature of Sugars] Why does sucrose need a higher temperature to caramelize than glucose or fructose?

    In sucrose, the reactive (reducing) atoms of glucose and fructose are tied up in the bond between them. So sucrose has no reactive atoms free until it splits.Caramelization: sucrose 170°C (340°F), glucose 150°C (300°F), fructose 105°C (220°F).

62. [The Nature of Sugars] Caramel is made by heating sugar with some water until the water has boiled off. Why add the water?

    No burning The sugar can be heated strongly from the start without burning. Stronger flavor Cooking takes longer, so the reactions have more time and develop more flavor than heating dry sugar quickly. Inversion Water helps split sucrose into glucose and fructose.

63. [The Nature of Sugars] Why can caramel suddenly burn once it starts to color?

    The browning reactions give off heat, which speeds them up further. Overcooked caramel becomes very dark, bitter, and thick or even solid.

64. [The Nature of Sugars] How can a cook stop caramel from overcooking once it is done?

    Set the pan in a bowl of cold water, kept ready beforehand.

65. [The Nature of Sugars] What aroma notes does simple caramelized sugar have?

    Buttery and milky (diacetyl), fruity (esters and lactones), plus flowery, sweet, roasted and rum-like notes. Other compounds: sherry-like acetaldehyde, vinegary acetic acid, fruity ethyl acetate, nutty furan, toasty maltol.

66. [The Nature of Sugars] How does the taste of caramel change as caramelization goes on?

    It gets less sweet and more acid, then bitter, and finally irritating and burning. Some caramel products are antioxidants that protect food flavors during storage.

67. [The Nature of Sugars] What happens besides caramelization when sugar is cooked with milk or cream?

    Sugars react with the proteins and amino acids in Maillard browning reactions, giving more compounds and a richer aroma.

68. [The Nature of Sugars] What is the most common food coloring?

    Caramel color, made commercially since the mid-19th century. Example: the brown of colas, root beer and spirits.

69. [The Nature of Sugars] In what sense are sugars "empty calories"?

    They supply energy but no other nutrients, and they take the place of foods that would. After fats and oils, sugars are the most concentrated source of calories.

70. [The Nature of Sugars] What share of their calories do Americans get from refined sugars?

    Adults about 20%, children 20 to 40%. Ingredient lists can hide the total by listing sucrose, dextrose, levulose, corn syrup etc. separately.

71. [The Nature of Sugars] Where does most of the refined sugar in the American diet come from?

    Soft drinks. Candies and confections supply much less.

72. [The Nature of Sugars] How do sugars cause tooth decay?

    Mouth bacteria turn sugar into sticky plaque and into acids that dissolve tooth enamel. The bacteria are Streptococcus species; the plaque holds them on the teeth.Hard candies that dissolve slowly in the mouth supply the bacteria with sugar for a long time.

73. [The Nature of Sugars] Why are starchy foods like bread and potato chips also bad for teeth?

    They stick to the teeth, and enzymes in saliva break their starch down into sugars.

74. [The Nature of Sugars] Which foods inhibit decay-causing bacteria in the mouth?

    Chocolate, cocoa, licorice extract, coffee, tea, beer and some cheeses. Phenolic compounds seem to stop bacteria from sticking to the teeth.

75. [The Nature of Sugars] Why don't sugar alcohols (sweeteners such as sorbitol and xylitol) cause tooth decay?

    Mouth bacteria generally can't feed on them.

76. [The Nature of Sugars] Why does the body keep blood glucose within tight limits?

    Excess glucose is reactive and damages blood vessels, eyes, kidneys and nerves. Glucose must still reach every cell through the blood, since it is the body's main fuel.

77. [The Nature of Sugars] Which hormone regulates blood glucose?

    Insulin. In diabetes, insulin fails to keep blood glucose properly under control.

78. [The Nature of Sugars] Which foods raise blood glucose the most, and which much less?

    Glucose and starchy foods (potatoes, rice) the most; table sugar less; fructose much less. Starch is digested to glucose; fructose must first be metabolized in the liver.

79. [The Nature of Sugars] What is the glycemic index of a food?

    A measure of how much the food raises blood glucose, with glucose itself = 100. Example: fructose 20, banana 60, white rice 95, maltose 110 (McGee's values).

80. [The Nature of Sugars] What are the two main kinds of sugar substitutes?

    Bulking carbohydrates Provide sugar-like bulk but are less digestible, so they give fewer calories and raise blood sugar more slowly. Example: sugar alcohols such as sorbitol. High-intensity sweeteners Hundreds or thousands of times sweeter than sugar, so tiny amounts give sweetness with almost no calories. Example: aspartame, saccharin. Low- and no-calorie sweets combine the two.

81. [The Nature of Sugars] What are sugar alcohols (polyols)?

    Sugars with one corner of the molecule chemically modified; their names end in -itol. Example: sorbitol is derived from glucose. Sorbitol and mannitol occur in small amounts in many fruits.

82. [The Nature of Sugars] Why do sugar alcohols give fewer calories than sugar?

    We absorb only part of them and use that part inefficiently; gut microbes consume the rest. So blood insulin rises only slowly after eating them.

83. [The Nature of Sugars] What fraction of the calories of sugar do sugar alcohols provide?

    50 to 75%.

84. [The Nature of Sugars] Why don't sugar alcohols brown when heated?

    They lack the aldehyde group that starts browning reactions, both among sugars and between sugars and amino acids. So confections made with them don't discolor or change flavor on heating.

85. [The Nature of Sugars] Which sugar alcohols give a cooling sensation?

    Sorbitol, mannitol, and especially xylitol.

86. [The Nature of Sugars] What is glycyrrhizin?

    The sweet compound of licorice root, 50 to 100 times sweeter than sucrose. Its sweetness builds slowly and lingers. Licorice was first made into a sweet by boiling down a hot-water extract of the root.

87. [The Nature of Sugars] Why can large doses of licorice extract cause high blood pressure?

    Glycyrrhizin interferes with the hormones that regulate blood volume and pressure, causing high blood pressure and swelling.

88. [The Nature of Sugars] What is stevioside?

    The sweet compound of the South American plant stevia (Stevia rebaudiana), used for centuries to sweeten maté tea. It has a woody aftertaste.

89. [The Nature of Sugars] Why are intensive sweeteners imperfect replacements for sugar?

    They have off-flavors, their sweetness comes slowly, and it lingers after swallowing. Example: saccharin has a metallic, sometimes bitter aftertaste; stevioside a woody one.

90. [The Nature of Sugars] Why do manufacturers often combine two or more intensive sweeteners?

    A combination tastes sweeter than its parts and hides their odd flavors. Each sweetener on its own becomes relatively less sweet as its concentration rises.

91. [The Nature of Sugars] What is aspartame?

    A synthetic combination of two amino acids, 180 to 200 times sweeter than sucrose. It has the same calories per gram as sugar, but tiny amounts are needed. It is the most widely used noncaloric sweetener.

92. [The Nature of Sugars] Why can't aspartame be used in cooked foods?

    Heat and acidity break it down.

93. [The Nature of Sugars] Which intensive sweeteners are stable at cooking temperatures?

    Saccharin, acesulfame K and sucralose. Example: sucralose (sucrose modified with chlorine) is about 600 times sweeter than sugar, saccharin about 300 times, acesulfame K about 200 times.

94. [The Nature of Sugars] What does lactisole do?

    It blocks the taste of sweetness: a tiny amount makes sugar taste only a third as sweet. It is a phenolic compound found in roasted coffee, used where a texture needs much sugar but less sweetness is wanted.

95. [Honey] In the 16th century, which sweetener took over from honey as the most important one in Europe?

    Cane sugar. Its sweetness is more neutral than honey's. Until then honey was Europe's main sweetener, and mead (honey wine) a favorite drink in central Europe and Scandinavia.

96. [Honey] Are honeybees native to North America?

    No: European colonists brought them around 1625. The New World's native bees (Melipona, Trigona) live only in the tropics, have no sting, and also collect fluids from fruits, resins and even carrion, which can make unhealthful honeys.

97. [Honey] Why do bees make honey?

    To store food for the colony: nectar concentrated until it keeps. Concentrated enough, it resists bacteria and molds until the bees need it.

98. [Honey] What is flower nectar mostly made of?

    Sugars: sucrose, glucose and fructose. The mix depends on the plant.Example: some nectars are mostly sucrose, some an even mix of the three sugars, and sage and tupelo nectars are mostly fructose.

99. [Honey] How can a honey be poisonous to humans?

    The bees made it from a nectar that is harmless to bees but poisonous to people. Example: honey from the Pontic region of eastern Turkey, notorious in ancient Greece and Rome, comes from a rhododendron whose grayanotoxins disturb lung and heart action.

100. [Honey] Why are chestnut and buckwheat honeys much darker than most honeys?

     Their nectars contain more protein, which reacts with the sugars to form dark pigments. The same browning reactions give them a toasted aroma.