Humans learned to consume other animals’ milk when they started domesticating the animals for meat and skins. It was discovered later that the domestic animals can be used for getting milk too. (Humans started drinking other animals’ milk sometime between 9000 - 8000 BC.)
Gradually, humans discovered that milk can be transformed into different forms, such as butter, yogurt, and cheese. Later, they became more skilled and started collecting greater quantities of milk and found new ways to concentrate and preserve its nourishment.
The milk that we use for cooking, including Sweetened Condensed Milk, serves primarily as a source of moisture, and adds flavor and body to the food. Sugar in the milk encourages browning while salts contribute to protein coagulation.
Sweetened condensed milk contains concentrated protein and sugar, which help it caramelize at temperatures as low as boiling point of water. This makes it a favorite shortcut to creamy caramel sauce and base for cooking several desserts.
It’s a common practice to put the can in a pot of boiling water or a warm oven and let it brown inside, which is potentially dangerous. Since any trapped air in the can will expand on heating and may cause the can to burst open. It’s safer to empty the can into an open utensil and then heat it on the stovetop, in the oven, or in the microwave.
You can find sweetened condensed milk at any grocery store, or buy it online at
amazon.com. You can also look for other online resources for more options.