Ash insoluble in water, not over 3 per cent.
Ash insoluble in acid ranges between 0·3 and 0·8 per cent.
Extract[8] ranges between 32 and 50 per cent.
Insoluble leaf ranges between 43 and 58 per cent.
The table below may prove useful as indicating the requirements to be exacted when the chemist is asked to give an opinion concerning the presence of facing admixtures, or of exhausted or foreign leaves in a sample of tea.
Total ash should not be under 4·5 per cent. or above 7 per cent.
Ash soluble in water should not be under 40 per cent. of total ash.
Ash insoluble in water should not be over 3·25 per cent.
Ash insoluble in acid should not be over 1 per cent.