Milk Cooker Views
When we boil the milk in normal vessel a scum like film of cogulated albumin, mineral salt such as calcium phosphate & fat globules forms. Milk also has water as one of its constituent, the water starts to boil & gets trapped in this film causing spill of the milk. But in milk cooker the milk is placed in a sort of hot bath of water.The heat is transferred from boiling water hot bath to milk,this avoids/lessens the agitated movement of the water molecule from milk thus spill over is saved, more over you always have the alarm in the form of whistle.
Thus, the area of the top covering layer gradually increases and the surface appears bulged out in order to accumulate a large amount of the water vapour. And at some point of time, the bulged-out sheet of cream outgrows the available space in the vessel, resulting in the spillage of the milk. On the other hand, when milk is heated in a milk cooker, all these above processes do not occur. The milk cooker is a double walled vessel with the annular gap containing water, which boils at a lower temperature than the boiling point of milk.