In India, clarified butter is the most eminent of all foods. It is mentioned in the Vedas as one of the most important ingredients along with honey for holy rituals. Aryans who entered into Punjab from the West were village dwellers and reared the cattle. This was in contrast to the stable city life the people of the Indus valley civilization lived before them. As the cattle herds required pastures for grazing, these people were always on the move and spread into whole of Punjab and then towards Ganges valley. Many stories and epics revolve around the possession of more cattle which were symbols of wealth. Many groups fought for the possession and even took away the cattle by force or other means.
In addition to being used as an ingredient and frying oil, the fuel of holy lamps and funeral pyres, it is an emblem of purity, an ancient offering to the gods. Ghee (from the Sanskrit for “bright”) was born of necessity. Due to the hot weather, ordinary butter spoils in only ten days in much of the country, while the clarified fat keeps six to eight months. Traditionally, ghee has been made from whole cow or buffalo milk that is soured by lactic acid bacteria into yogurt-like dahi then churned to obtain butter, cream. Today, industrial manufacturers usually start with cream.
The preliminary souring improves both the quantity of butter obtained and its flavor; ghee made from sweet cream is said to taste flat. The butter is heated to 190ºF/90ºC to evaporate its water then the temperature is raised to 250ºF/120ºC to brown the milk solids, which flavors the ghee and generates antioxidant compounds that delay the onset of rancidity. The brown residue is then filtered off (and mixed with sugar to make sweets) leaving the clear liquid ghee.
Yogurt is the fermentation product of milk. In India, it is part of food consumed by the village people. Buttermilk is made from it and in summers it gives refreshment and energy. It has a cooling effect and promotes digestion because it contains probiotic-the “good bacteria” in addition to Calcium, proteins.
As in most of transformations, the process of converting milk into yogurt is carried out by bacteria. Yogurt forms when bacteria ferment the sugar lactose (C12H22O11) into Lactic acid (C3H6O3).
You can make yogurt from any type of milk. Although most yogurt is made from bovine milk (e.g., cow, sheep, goat), the fermentation process works on other types of “milk”, as long as they contain a sugar for the bacteria to ferment and protein that can be coagulated. Yogurt can be made from soy milk, coconut milk, and almond milk.
The first time you make yogurt, you need a starter culture as a source of the bacteria. You can use ordinary store-bought yogurt with active culture or you can use freeze-dried yogurt starter. Milk is inoculated with the stored bacteria culture which begin to multiply and convert sugars into Lactic acid. The bacteria work optimally at 100°F (38°C). So the temperature should be maintained as close as possible to this temperature and milk undisturbed.