Food Adulteration and Its Detection / With photomicrographic plates and a bibliographical appendix

by Jesse P. Battershall

Extract (excepting in poor varieties of Congou tea) should not be under 30 per cent.

Insoluble Leaf should not be over 60 per cent.

The British Society of Public Analysts adopt:—

Total ash (dry basis), not over 8 per cent. (at least 3 per cent. should be soluble in water).

Extract (tea as sold), not under 30 per cent.

Below are the proportions of total ash, ash soluble in water, and extract found in 850 samples of tea (mostly inferior and faced), examined under the direction of the author in the U.S. Laboratory:—

Total Ash.

Range	5 to 5½ per cent.	5½ to 6 per cent.	6 to 6½ per cent.	6½ to 7 per cent.	7 to 8 per cent.	8 per cent. and over.
Number	21	76	102	194	421	36
Per cent.	2·47	8·94	12·00	21·64	49·53	4·23

Ash Soluble in Water.

Range	Under 2 per cent.	2 to 3 per cent.	3 to 3½ per cent.	3½ per cent. and over.
Number	25	649	157	19
Per cent.	2·94	76·35	18·70	2·23