Milk is condensed by evaporating water from it and adding sugar to achieve a specific sugar-to-milk ratio, which helps preserve the final product.
Condensed milk production primarily involves reducing the water content of fresh milk. This process concentrates the milk solids and creates a thicker, sweeter product. Here's a more detailed explanation:
-
Evaporation: Fresh milk is heated under a vacuum to lower its boiling point. This allows water to evaporate more efficiently at a lower temperature, preserving the milk's flavor and color. The evaporation process typically removes about 60% of the water content.
-
Sugar Addition: After evaporation, sugar (typically sucrose) is added. The final sugar-to-evaporated milk ratio is approximately 9:11. The high sugar concentration is crucial for preservation, as it increases the osmotic pressure, inhibiting microbial growth and preventing spoilage.
-
Cooling and Crystallization: The mixture is then cooled, and controlled crystallization of the lactose is initiated. This step is vital for preventing the formation of large, gritty lactose crystals, ensuring a smooth texture.
-
Packaging: Finally, the condensed milk is packaged and sealed to prevent contamination and maintain its shelf life.
Essentially, the combination of water removal and high sugar content creates an environment where spoilage microorganisms cannot thrive, giving sweetened condensed milk its extended shelf life.
