The document discusses various quality control tests performed on syrups and elixirs, including testing the water used, visual inspection, measuring pH, testing for sucrose concentration using HPLC or UV spectroscopy, determining alcohol concentration, and measuring viscosity. Viscosity can be measured using various methods like U-tube viscometers, capillary viscometers, rotating viscometers, concentric cylinder viscometers, cone-plate viscometers, and spindle viscometers. Maintaining quality standards is important to ensure purity, appearance, stability, and proper concentration of ingredients in syrups and elixirs.