Usually it is fresh milk by vacuum concentration or other methods to remove most of the water, concentrated to the original volume of 25% to 40% or so of the dairy product, and then add 40% of the cane sugar canning made. Condensed milk is too sweet and must be diluted with 5-8 times water. But when the sweetness is up to snuff, often the protein and fat concentrations have also dropped by half compared to fresh milk. If water is added to condensed milk to bring the protein and fat concentration closer to that of fresh milk, then the sugar content will again be high .
Condensed milk is usually sold in large supermarkets. The price is usually around 10 dollars.