Natural History of the Tea Tree
The tea tree (Polyandria Monogynia) is a native of China, Japan, and Tonquin, it has never been found growing wild in any other country. Linnæus says, that there are two species of this plant, the Bohe´a, or black, and the Vir´idis, or green tea. The green has much longer leaves than the black, it is a more hardy plant; and, with very little protection, bears the severity of our winters. The tea is planted in China round borders of fields, without regard to the soil.
The tree attains the height of ten or twelve feet, and is an evergreen: the leaves, which are the only valuable part of it, are about an inch and a half long, and resemble those of sweet brier. The flowers are something like the wild white-rose; the seeds are round, and blackish, about the size of a large pea.
As tea is a most important article of commerce to the Chinese, they bestow the greatest possible care upon its cultivation.
The people of China and Japan take as much pains to procure tea, of excellent quality, as the Europeans do to obtain good wine; they generally keep it a year before they use it.
Tea is propagated by seeds, which are put into holes about five inches deep, at regular distances from each other; from six to twelve being sown together, as it is supposed that only a small number grow.
When the tree is three years old, the leaves are fit to be gathered; and the men who collect them wear gloves that the flavour may not be injured. They do not pull them by handfuls, but pick them off one by one, taking great care not to break the leaves, and although this appears to be a very tedious process, each person gathers from ten to fifteen pounds a day. The tea leaves are collected at three different seasons: what are first procured, while the leaves are very young, are called imperial tea, being generally reserved for the court and people of rank, because they are considered as of the finest quality. The last gathering, when the leaves have attained their full growth, is the coarsest tea of all, and is used by the common people.
The leaves are first exposed to the steam of boiling water, after which they are put on plates of copper, and held over a fire until they become dry and shriveled; they are then taken off the plates with a shovel, and spread upon mats, some of the labourers taking a small quantity at a time in their hands, which they roll in one direction, while others are continually employed in stirring those on the mats, in order that they may cool the sooner, and retain their shriveled appearance. The adulteration of tea38 has been practised in this country to an enormous extent.
OBSERVATIONS ON THE ART OF MAKING TEA, AND SINGULAR EFFECTS OF DIFFERENT KINDS OF TEA POTS, ON THE INFUSION OF TEA.
It has been long observed, that the infusion of tea, made in silver or polished metal tea-pots, is stronger than that which is produced in black, or other kinds of earthenware pots. This remark is explained on the principles, that polished surfaces retain heat much better than dark rough surfaces, and that, consequently, the caloric being confined in the former case, must act more powerfully than in the latter. It is further certain, that the silver or metal pot, when filled a second time, produces worse tea than the earthenware vessel; and that it is advisable to use the earthenware pot, unless a silver or metal one can be procured sufficiently large to contain, at once, all that may be required. These facts are readily explained, by considering that the action of heat, retained by the silver vessel, so far exhausts the herb, as to leave very little soluble substance for a second infusion; whereas, the reduced temperature of the water in the earthenware pot, by extracting only a small portion at first, leaves some soluble matter for the action of a subsequent infusion.
The reason for pouring boiling water into the teapot, before the infusion of the tea is made, is, that the vessel, being previously warm, may abstract less heat from the mixture, and thus admit a more powerful action. Neither is it difficult to explain the fact, why the infusion of tea is stronger if only a small quantity of boiling water be first used, and more be added some time afterwards, for if we consider that only the water immediately in contact with the herb can act upon it, and that it cools very rapidly, especially in earthenware vessels, it is clear that the effect will be greater where the heat is kept up by additions of boiling water, than where the vessel is filled at once, and the fluid suffered gradually to cool. When the infusion has once been completed, it is found that any further addition of the herb only affords a very small increase in the strength, the water having cooled much below the boiling point, and consequently acting very slightly.
Notes
38 Adulteration of Food and Culinary Poisons, and Methods of Detecting them.—See article Tea.—1821.