What is Kalai
Kalai is the process where brass and copper utensils used for cooking and eating are coated with a metal called Kalai. The Kalai coating fades with use and needs to be re-tinned after 6-8 months of usage. Brass and copper tend to react to souring agents in food and thus giving them a Kalai lining is a must.
Why it is necessary
When a brass utensil is used for cooking purpose, the metal copper present in the alloy reacts with organic acids present in the foodstuff to form products that may cause food poisoning.
Advantage of Kalai
A bright white coating of tin protects the metal from its reaction with organic acids of the foodstuff.