The solubility of the sugars determines their use to a certain extent. It is obvious to one who does a great deal of cooking that a sugar that requires 6 pounds of water to dissolve 1 pound of sugar, could not be used for concentrated sugar products like jellies, jams, frostings, or even cakes.

Sucrose. Sucrose has the greatest solubility of the disaccharid sugars. Browne in his "Handbook of Sugar Analysis" states that, at 20°C, 204 grams are soluble in 100 cc. of water. Thus at room temperature about 2 grams of sucrose are soluble in 1 cc. of water. At 100°C. 487 grams of sucrose are soluble in 100 cc. of water. For solubilities at other temperatures see Table 5.

In Table 5 the solubility of sucrose is expressed in two ways. In column 2 is given the amount of sucrose dissolved in water to make 100 grams of solution. Thus at 0°C, 64.18 grams of sucrose are dissolved in 35.82 grams of water to give a total of 100 grams of solution. The third column states the number of grams of sucrose dissolved in 100 grams of water at a definite temperature.

Table 5 Solubility of Sucrose in Water at Different Temperatures

(From Browne's "Handbook of Suzar Analysis")

Temperature, degrees C.

Grams of sucrose in 100 grams of solution, or per cent

Grams of sucrose dissolved by 100 grams of water

Specific gravity of solution

0

64.18

179.2

1.31490

5

64.87

184.7

1.31920

10

65.58

190.5

1.32353

15

66.30

197.0

1.32804

20

67.09

203.9

1.33272

25

67.89

211.4

1.33768

30

68.70

219.5

1.34273

35

69.55

228.4

1.34805

40

70.42

238.1

1.35353

45

71.32

248.7

1.35923

50

72.25

260.4

1.36515

55

73.20

273.1

1.37124

60

74.18

287.3

1.37755

65

75.18

302.9

1.38404

70

76.22

320.5

1.39083

75

77.27

339.9

1.39772

80

78.36

362.1

1.40493

85

79.46

386.8

1.41225

90

80.61

415.7

1.41996

95

81.77

448.6

1.42778

100

82.87

487.2

1.43594

Percentage of Sucrose in Saturated Solutions. From Table 5 the percentage of sugar may be obtained. At 0°C, 64.18 grams of sugar and 35.82 grams of water give 100 grams of solution, so that the number of grams of sugar may be read as percentage of sucrose or 64.18 per cent.

Maltose. Maltose is not a common sugar on the market. When used to make jelly, it crystallizes from the jelly, like dextrose. Gillis has reported the following solubility.

Lactose. The use of lactose in the home is limited because it is not very soluble and lacks sweetness. According to Greenleaf, if lactose is crystallized below 93.5°C. the alpha hydrate form is obtained. Above 93.5°C. the beta lactose is formed. Beta lactose is about one-fourth sweeter than alpha hydrate and dissolves more rapidly, hence does not leave a sandy sensation in the mouth. Hudson states that at the final solubility of lactose there are 11/2 parts of the anhydrous to 1 of the hydrate. Hunziker and Nissen state that its solution is complete after shaking it 170 hours at constant temperature. Herrington found that the addition of calcium chloride to a lactose solution increased the solubility of lactose from 28.6 to 29.5 grams per 100 grams of water at 32°C. An analysis of the precipitate showed the crystals to be a compound of lactose with calcium chloride. The following table of solubility of lactose is from Hudson.