Analysis of Tea by Dr. Hassall.
| Black. | Green. | |
|---|---|---|
| Water | 11.56 | 9.37 |
| Tannin | 15.24 | 18.69 |
| Gum | 5.70 | 5.89 |
| Albuminous matter | 15.55 | 24.39 |
| Theine | 2.53 | 2.79 |
| Ash | 5.82 | 5.38 |
| Chlorophyle, etc. | 5.24 | 1.83 |
| Cellulose and other matter insoluble in water | 38.36 | 31.66 |
| —————— | —————— | |
| 100.00 | 100.00 |
The aroma and commercial value of tea are due to a small quantity, (from 1/4 to 1 per cent.) of a volatile oil which it contains. This oil, as in coffee, is developed by roasting, the fresh picked leaves having neither an astringent, aromatic, nor bitter taste. But the effects of tea are due to its theine and tannin. Theine is present in all kinds of tea, as well as in coffee and cocoa, but it has no flavor. Tannin forms from a fifth to a seventh of the weight of the dried tea leaf, and is the more completely extracted the longer the tea is infused, or “draws.” Its precise effect upon the system is not fully known. Black tea contains less theine, essential oil, and tannin, than green tea.
The Chinese pour hot water upon their tea, and drink it clear, and in Russia a squeeze of lemon takes the place of our cream. The Chinese sometimes flavor their fine teas with the cowslip colored blossoms of the sweet-scented olive and other odoriferous plants; and they also adulterate them with foreign or exhausted tea leaves, or with tea dust, called “Lie tea.” But good authorities declare that fair grades of tea are not now much or necessarily adulterated, and that the old idea that green teas are colored or faced with copper is erroneous; at least experts have not been able to detect even traces of it.