1, sugar conversion and crystallization Sugar is soluble in water and the formation of sugar solution. At room temperature, 2 parts of sugar can be dissolved in 1 part of water to form a saturated solution. Under heating conditions, the amount of sugar in the sugar solution can even reach more than 3 times the amount of water, that is, the supersaturated solution. When it is stirred or placed, the sugar will crystallize from the solution, a phenomenon known as sugar recrystallization, commonly known as sugar back to the sand. Because sucrose has coarse crystalline particles, it is sometimes necessary to inhibit this crystallization.
When a sugar solution is heated to boiling, the sucrose molecules are hydrolyzed to 1 molecule of fructose and 1 molecule of glucose. This action is known as sugar conversion, the two products are called converted sugar. Sugar solution after heating and boiling will become syrup, also known as the conversion of syrup. The degree of conversion of sugar has an important effect on the recrystallization properties of sugar. Because converted sugar is not easy to crystallize, so the higher the degree of conversion, the less sucrose can be crystallized, the lower the role of sugar crystallization. Controlling the rate of the conversion reaction can control the crystallization of sugar to some extent. Acid (such as organic acids) can catalyze the conversion reaction of sugar, glucose has fine grains, both can inhibit the crystallization of sugar back to the sand, or get fine crystals (microcrystalline), so that the products are fine and bright. In the production of paste decorations such as cream paste and egg white paste, usually to boil the sugar syrup to 116 to 118 ℃, to achieve this degree of conversion of sugar syrup, when added to whipped cream or egg whites, not only can form a smooth sugar paste, but also due to the high viscosity of the syrup, so that the egg whites or cream in the foam more stable.
2, syrup boiling process and characteristics
Syrup in the boiling process, the water continues to evaporate, the concentration of sugar solution gradually increased, becoming more and more viscous, boiling temperature (boiling point) is also a progressive increase. The boiling temperature (boiling point) also rises progressively. There is a certain correspondence between the syrup concentration and the boiling point. In addition to the use of sugar meter, but also by the physical characteristics of the syrup to determine the temperature and concentration of the syrup, so as to grasp the syrup boiling whether the required temperature has been reached.
The following introduction to the "hand-measurement method" to identify a number of stages of syrup boiling and the corresponding temperature.
(1) the beginning of the boiling stage 104.5 ℃, sugar bubbling.
(2) into the line stage 107 ℃, with the index finger touching the surface of the syrup, and then with the thumb together, and then separate the two fingers, you can pull the syrup into a stretchy thin sugar line.
(3) Pearl stage 110℃, the same method as above; when the thread breaks, a liquid pearl can be formed at the end.
(4) Blowing Stage 113°C, with a loop of wire stretched into the syrup and then taken out; a film can be formed in the loop, and the film can be gently blown.
(5) Feather stage 115 ℃, the syrup film can be blown into a feather.
(6) soft ball stage 118 ℃, dipped in a little syrup, drops into cold water, that is, two fingers pinch the sugar droplets, when the two fingers gently rubbed, you can feel the syrup between the fingers to form a plasticity of the soft ball.
(7) hard ball stage 121 ℃, the same method as above, the syrup to form a solid hard ball.
(8) Soft shell stage 132 to 138 ℃, the sugar ball surface has a thin shell, and will be slightly broken.
(9) hard shell stage 138 ~ 154 ℃, the surface of the sugar ball into a layer of thick shell, and need to use a greater force to make it broken.
(10) caramel stage 154 ~ 180 ℃, the sugar becomes amber color, and with the increase in temperature from light to dark.
3, syrup boiling method
① sugar and water (about half of the sugar) into a clean pot, placed on a small fire heating, while constantly stirring until the sugar is completely dissolved.
②Turn up the heat and continue heating until the sugar comes to a boil. If you need to add organic acid (such as citric acid) or glucose, you can add it at this time.
③Once boiling, stop stirring. If sugar crystals appear at the edge of the pot, use a small amount of water to rinse them into the sugar solution. Skim off the surface froth at any time during the boiling process.
④Quickly boil the syrup to the desired temperature while it lasts
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