How to Test Tea Leaves for Adulteration (Spent Tea Leaves, Iron Filings, Coal Tar Dyes)

Tea is often adulterated with "spent" (already used and dried) leaves, which are then dyed with toxic coal tar colors to look fresh. Iron filings are also added to increase weight.

1. The Filter Paper Test (Dyes):
Spread a teaspoon of tea leaves on a wet white filter paper or a damp white cloth. Rub the leaves gently. If the paper/cloth turns yellow, orange, or red immediately, it indicates the presence of Coal Tar Dyes. Pure tea only leaches color slowly when heated.

2. The Magnet Test (Iron Filings):
Run a strong magnet over a spread of tea leaves. If tiny black particles cling to the magnet, it confirms the presence of Iron Filings, which can cause serious internal injury.

3. The Cold Water Test:
Add a spoonful of tea leaves to a glass of cold water. Pure tea will not leach any color into cold water. If the water turns reddish-brown immediately, the tea has been artificially colored.

4. The Friction Test (Used Leaves):
Rub the dry tea leaves between your fingers. If they feel extremely soft or crumble like paper without any natural 'grain' or aroma, they may be spent tea leaves that have been reprocessed.