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Coating brass utensils



PHOTO: KAMAL NARANG

Why are brass utensils enamelled before being used for cooking purposes?

Abhayakumar Shah
Adoni, Andhra Pradesh

Chemically, brass is an alloy of the metal copper with zinc, having varied compositions — 60 to 80 per cent copper and 40 to 20 per cent zinc.

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.

Enamelling these before being used for cooking purposes therefore protects the utensils and the food.

The traditional method for this is to coat the alloy surface by deposition of the metal tin on it.

The metal surface is cleaned thoroughly, it is the heated with a little ammonium chloride, a small amount of tin is applied to the alloy surface, the molten tin is now spread on whole of the surface with cotton and the alloy is washed thoroughly with water.

A bright white coating of tin protects the metal from its reaction with organic acids of the foodstuff.

Dr. S.K. Aggarwal
Prof. and Head, Applied Sciences
Amritsar College of Engg and Technology
Amritsar

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