Sugar usually come in crystal form. Wait, It is not usual. It is crystal most of the time. It is used to sweetened coffee, milk, tea, and thousand of mouthwatering foods. For food preparations, crystal sugar can be mixed directly to other ingredients. Or it can be converted to syrup beforehand.
There are cases which syrup is preferred over the crystal form.
1) Crystal dissolved easily in water. Dissolving it in foods such as fruit pulp is a different story. Mixing time will take longer than expected. The worst, sugar might not be dissolved completely. On the other hand, mixing syrup with other ingredients is easy. No problems with undissolved components.
2) For sanitary purposes. Refined white sugar is supposed to be the cleanest sugar. However, it might still contain some impurities. Cooking it to syrup and filtering will help remove trace dirt.
3) Sugar crystals when added to food in process might get contact with sides of cooking vessel. Heat could be enough to cause burnt and produce off flavor.
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