Culinary Chemistry / The Scientific Principles of Cookery, with Concise Instructions for Preparing Good and Wholesome Pickles, Vinegar, Conserves, Fruit Jellies, Marmalades, and Various Other Alimentary Substances Employed in Domestic Economy, with Observations on the Chemical Constitution and Nutritive Qualities of Different Kinds of Food.

by Friedrich Christian Accum

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.