Green & Black Tea Benefits
Posted by admin in Green tea benefits, Tea fermentation on June 24th, 2009
Tea is a preparation made from the leaves of an evergreen plant known as Thea. It is grown in China, Japan, India, Ceylon, and in North Carolina. There are many varieties of the plant, and the flavor of tea varies with its source and the variety of the plant. There are two great classes of teas, the green and the black, the distinction between the two being due to the method of preparation. Several times during the year the plant sends out young shoots, which are picked as often as they appear. Black tea is prepared by exposing the fresh leaves to the rays of the sun; after they have become withered the constituents are liberated by rolling and breaking up the fibers and cells of the leaf. The broken-up leaves are then collected and allowed to ferment while still moist; during this process the tannic acid is rendered less soluble while the essential oils are increased. After again exposing them to the sun the leaves are dried in an oven. In the process of preparing green tea the Chinese “wither” the leaves in pans at a temperature of 160° F.; the Japanese steam them. The fluid principles are then liberated by breaking up the leaves; finally they are again withered, sweated in bags, and slowly roasted. The chief difference between black and green tea lies in the fact that black tea is fermented while green is not. As in the process of fermentation the tannic acid becomes less soluble, black tea contains much less tannic acid than green tea. The following table, from Bannister,1 gives the composition of black and of green tea:
Black tea. Green tea.
Water 8.20 5.96
Caffein 3.24 2.33
Albumin (insoluble) 17.20 16.83
Albumin (soluble) 0.70 0.80
Alcoholic extract 6.79 7.05
Dextrin 0.50
Pectin and pectic acid 2.60 3.22
Tannic acid 16.40 27.14
Chlorophyll and resin 4.60 4.20
Cellulose 34.00 25.90
Ash 6.27 6.07
Tea has practically no nutrient-ingredients. Its principal constituents are caffeine and tannic acid, and its special aroma is due to a volatile oil. It owes its stimulating effect to the presence of caffeine. As the action of tannic acid is detrimental to the process of digestion, tea should be so prepared as to contain as large a proportion of caffeine as possible and the smallest possible amount of tannic acid.
When the leaves are placed in boiling water, caffeine is extracted very rapidly. Tannic acid, however, is much less soluble; it follows, therefore, that in order to have as little tannic acid in the tea as possible, the leaves should be boiled in water for as short a time as practicable. To prepare the infusion pour boiling water on the tea- leaves and allow the mixture to stand where it will keep hot, though not boil, for from three to five minutes. Water used in preparing tea should not be hard or stale.
When the tannic acid which tea contains occurs in large quantities, the pepsin of the gastric juice is precipitated; in weaker solutions tea retards digestion. For these reasons tea is not a suitable beverage for persons suffering from gastric disturbances. Among the more prominent symptoms of excessive tea-drinkmg are gastric disorders, cardiac distress, and a variety of nervous symptoms, such as excitability, sleeplessness, and muscular incoordination.
Citation: pgs 176 - 180;
Diet in health and disease
By Julius Friedenwald, John Ruhräh
Green Tea & Energy
Posted by admin in Green tea benefits on June 2nd, 2009
Tea is a very favorite beverage, but it affords no direct nutriment; the sugar and cream or milk usually taken with it yield the nutritious elements. But though yielding no absolute aliment, tea, when taken in moderation, exhilarates, restores nervous energy, conserves force, retards the waste of tissues, enabling the food to go further in its nutritive action, and facilitates the transformation of other food, and particularly of fatty and farinaceous matters ; the body is revived, the mind is stimulated, wakefulness is promoted, and hunger is better borne. When consumed in large quantities, tea acts prejudicial on the nervous system. It then promotes nervous agitation, muscular tremors, prostration, and palpitation ; it may also cause nausea, derangement of the stomach, and abdominal pains. Green tea, even when genuine, is stronger than black, possesses more active properties, and is therefore to be used with more caution. Both kinds, when adulterated, are more or less injurious.
“To express in a few words the advantages derivable from the use of tea, it may be said that it forms an agreeable, refreshing, and wholesome beverage, and thereby constitutes a useful medium for the introduction of a portion of the fluid we require into the system. It secures that the water consumed is rendered safe for drinking by the boiling which is necessitated as a preliminary operation in making tea. It cools the body when hot, probably by promoting the action of the skin; and warms it when cold, by virtue, it would seem, of the warm liquid consumed. In a negative way it may prove beneficial to health by taking the place of a less wholesome liquid. Through the milk and sugar usually consumed with it in England it affords the means of supplying a certain amount, and not by any means an insignificant amount, viewed in its entirety, of alimentary matter to the system. Experience shows that it often affords comfort and relief to persons suffering from nervous headache. It also tends to allay the excitement from, and counteract the states induced by, the use of alcoholic stimulants; and further, on account of its anti-soporific properties, like coffee, is useful as an antidote in poisoning by opium.” (Pavy.)
Tea, then, is hurtful,—i. To those of spare habit and the underfed. 2. To the young, who are provided with the full amount of vital activity. 3. To those who perspire too freely. 4. Early in the day, for it is then apt to increase tissue waste. 5. To nervous, hysterical subjects, or to those whose hearts’ action is very weak.
On the other hand, it is beneficial,—i. For the overfed and sedentary, for they require increased vital action. 2. For the old, whose vital activity is deficient. 3. For those who have a non-perspiring skin. 4. During the after part of the day, when the system is full of partly digested food, for then the process of digestion requires to be quickened. 5. During excessive heat, in order to relax the skin and relieve internal congestion. 6. For those whose nervous systems are firmly braced up.
As commonly prepared, tea is often the cause of much Dyspepsia, particularly when drunk in excessive quantities, or too frequently, that is, as a rule, more than once a day. In some nervous and gastric disorders tea and other hot beverages are better discontinued, at least for a time. In this way intractable cases have often been cured. Dyspeptics, suffering from flatulent indigestion, should take tea in very moderate quantities only, as an excess of fluid increases the gaseous distention of the abdomen. Dispensary patients, especially poor women, often drink tea at every meal, and much ill-health is the consequence. When tea causes loss of appetite, palpitation of the heart, mental excitement, or sleeplessness, obviously its use should be relinquished. Tea should never be given to children, even though largely diluted. The common practice of adding a small quantity to milk-and-water begets a relish for it, leading to its use at an age when the nervous and muscular systems require no such aid.
Tea taken with animal food—” tea-dinners,” or ” meat-teas,” as they are called—is more liable to produce indigestion than when the meal consists chiefly of bread and butter. Two or three hours after dinner, when digestion has proceeded too far to be much interfered with, the habit of taking one or two small cups of tea is usually unobjectionable; but tea is always better avoided at bedtime.
In the preparation of tea three principles are extracted; one aromatic (oil), another nitrogenous (theine), the other astringent and bitter (tannin). The last, the cause of gastric disorder, is only given off after prolonged infusion; whereas the aromatic oil and theine are completely extracted in about two minutes. Hence to make tea, especially for the dyspeptic, it should be made by pouring boiling water (not water that has boiled) on the leaves, and allowing it to stand for two minutes. It may then be poured off into a heated teapot, so as to separate it from the leaves. Thus prepared, tea is not so likely to cause flatulence; but it is less economic than the ordinary method, much more tea being required to give flavour. If the tea be good the infusion will be fragrant, not very deep in colour, not harsh nor bitter to the taste. The leaves should not be boiled, otherwise the peculiar volatile aromatic principle is dissipated; nor, for the same reason, should the infusion stand long; in this case also too much roughness and bitterness are added to the flavour by the extraction of tannin. This tannin, though it makes the tea look strong, is worse than useless, inasmuch as it renders the food taken with the tea insoluble and indigestible. The finest teas colour the water the least. In an ordinary infusion the first cup of tea is also the best, having more of the choice flavour and aroma, and less of the astringency and colour. River water makes the best tea; soft water is to be preferred to hard; but soda should not be used, for it only extracts the astringent tannin. The water should only boil once, immediately before using it, and not for hours, as is sometimes the case; the teapot should be quite dry, as well as hot, when the leaves are put into it, and the infusion, as before stated, not allowed to exceed two minutes.
Teapots that retain the heat are better than those that allow it to pass off readily; hence unglazed earthenware teapots should not be used; but well- glazed earthenware, or porcelain, are suitable; and brightly polished silver teapots are the best, for they radiate much less heat than any other material.
The Chinese drink their tea without any admixture; the Russians add lemon-juice; the English, sugar and cream or milk.
The use of sugar in tea.—Except in small quantity, tea should be given up by persons who have a tendency to become corpulent. According to some tastes, the flavor of tea is improved by substituting lemon for cream or milk,—pouring the hot tea over a slice of lemon cut with the rind upon it. Besides being more palatable, the lemon-juice more effectually allays thirst, and is especially valuable at those seasons of the year when fruits and fresh vegetables are not generally to be obtained.
” The best tea is that which is pleasantest to the taste of the educated customer, and which contains most of the characteristic sedative principles. The sedative principles in the leaf consist of an essential oil—which may be smelt strongest in the finest teas, weakest in the inferior sorts, entirely absent in fictitious teas—and of the alkaloid theine, which may be demonstrated by heating some tea, dry, in a silver pot, when the salt will appear as a white bloom on the metal. If there is any bouquet at all, or any theine at all, in the specimen examined, it is worth something.”
” The shortest way to test the comparative value of different specimens is to put a teaspoonful of each in one of the little china teapots or cups with covers, here used as ornaments, but originally intended for this very purpose, which has been previously made quite hot; shake the tea about in the hot pot a few seconds and then pour on, quite boiling, a small half- cup of water on each. Cover them up quickly and let them stand by the fire about a minute. Taste them immediately, without milk or sugar, and choose that which has most aroma.”—Dr. Chambers.
Coffee contains the same principle as tea, and hence has an analogous influence on the system. It is, however, more heating and stimulating, heavier and more oppressive to the digestive organs, and decidedly increases the force and frequency of the pulse. Its effect upon the mental faculties, quickening their energies and causing wakefulness, is not so marked as in the use of tea. It, however, relieves hunger and fatigue, and thus enables soldiers on heavy marches to undergo arduous exertion; it appears to have a staying power, lessening the amount of waste, and thus economizing other food. It is laxative to some and constipating to others, and is serviceable in warming the body in cold weather; it is also cooling in warm weather by stimulating the action of the skin, though COFFEE. 107
not so much so as tea. It has been found beneficial to those weary from traveling in the heat and suffering from want of food, also in diarrhea from overwork with anxiety. If taken in excess it produces feverishness, palpitation, anxiety, deranged vision, headache, wakefulness and nervous excitement. It is employed as a therapeutic by the new school of medicine. It thus relieves headache, soothes nervous excitability, and when given strong counteracts the effect of alcohol….
Citation: pgs. 100-104
Tea, “the Drink of Health”
Posted by admin in Green tea benefits on May 30th, 2009
The benefits derived from the use of Tea can be fairly estimated, it may be said, in the language of an eminent statesman : ” What was first regarded as a luxury, has now become, if not an absolute necessity, at least one of our accustomed daily wants, the loss of which would cause more suffering and excite more regret than would the deprivation of many things which once were counted as necessaries of life.” Consumed by all classes, serving not simply as an article of diet, but as a refreshing and invigorating beverage, Tea cannot be too highly estimated. The wisdom of successive financiers, and the enterprise of generations of merchants, have combined to deliver Tea in this country at a price which brings it within the reach of every individual, making it, perhaps, the only real luxury which is common to rich and poor alike.
In noticing Dr. Johnston’s work, entitled “The Chemistry of Common Life,” the Edinburgh Revieir thus emphatically attests the great boon which Tea confers upon the people. It remarks : ” By her fireside, in her humble cottage, the lonely widow sits ; the kettle simmers over the ruddy embers, and the blackened tea-pot on the hot brick prepares her evening drink. Her crust of bread is scanty, yet as she sips the warm beverage—little sweetened, it may be, with the produce of the sugar-cane—genial thoughts awaken in her mind; her cottage grows less dark and lonely, and comfort seems to enliven the ill-furnished cabin. When our suffering and wounded soldiers were brought down frozen and bleeding from the trenches before Sebastopol to the port of Bulaklava, the most welcome relief to their sufferings was a pint of hot Tea, which was happily provided for them. Whence this great solace to the weary and worn ? Why out of scanty earnings does the ill-fed and
Along one cheerfully pay for the seemingly un-nourishing weekly allowance of Tea ? From what ever-open fountain does the daily comfort flow which the tea-cup gently brings to the care-worn and the weak?”
Anon, referring to the chemical action of two important agents present in Tea—theine and volatile oil—the same excellent authority gives the following account of their operations on the human organism : ” The theine is a substance possessing tonic or strengthening qualities, but distinguished particularly by the property of retarding the natural waste of the animal body. Most people are now aware that the chief necessity for food arises from the gradual and constant wearing away of the tissues and solid parts of the body. To repair and restore the worn and wasted parts, food must be constantly eaten and digested. And the faster the waste, the larger the quantity of food which must daily be consumed, to make up for the loss which this waste occasions. Now, the introduction of a certain quantity of theine into the stomach lessens the amount of waste which in similar circumstances would otherwise naturally take place. It makes the ordinary food consumed along
with it, go farther, therefore, or, more correctly, lessens the quantity of food necessary to be eaten in a given time. A similar effect, in a somewhat less degree, is produced by the volatile oil, and, therefore, the infusion of Tea, in which both these ingredients of the leaf are contained, affects the rapidity of the natural waste in the Tea drinker, in a very marked manner.
” As age creeps on, the powers of digestion diminish with the failing of the general vigour, till the stomach is no longer able to digest and appropriate new food as fast as the body wears away. When such is the case, to lessen the waste is to aid the digestive powers in maintaining the strength and bulk of the weakening frame. ‘ It is no longer wonderful, therefore,’ says our author, ‘ that Tea should be the favorite on the one hand, with the poor whose supplies of substantial food are scanty; and, on the other, with the aged and infirm, especially of the feebler sex, whose powers of digestion, and whose bodily substance have together begun to fail.’ Nor is it surprising that the aged female whose earnings are barely sufficient to buy what are called the common necessaries of life, should yet spare a portion of her small gains in procuring this grateful indulgence. She can sustain her strength with less common food when she takes her Tea along with it; while she, at the same time, feels lighter in spirits, more cheerful, and fitter for this dull work of life, because of this little indulgence.”*
Such an indispensable article as Tea has now become, ought to be trebly guarded against all adulteration. While the Government is unable to protect the public against the machinations of unscrupulous Chinese merchants, let the public at least endeavor to protect itself. And this it can readily accomplish. Let it but bestow its custom on a trader upon whose integrity and technical knowledge it can implicitly rely. Let it insist upon having both its black and green Teas of the natural hue, without the addition of ” face,” ” glaze,” or artificial color, which but detract from its character and value. How such a discreet selection can be effected has already been pointed out. Houses of repute—such, for example, as that of Messrs. Horniman and Co.—do not conceal their names behind a retailer, but boldly give their own, coupled with a, guarantee to every purchaser, however modest his purchase. Hence, consumers may feel assured that in buying indirectly from them, the commodity they obtain will not only be free from adulteration and artificial color, but will be so carefully selected from the choicest growths, commensurate with the price demanded, as to be “always good alike.”
Citation: pg 70-77;
Infusions With Green Tea
Posted by admin in Green tea benefits on May 28th, 2009
There is no subject connected with diet, that has been more frequently discussed, or concerning which a greater variety of opinions have been entertained, than the use of tea, which, by some, is decried as a poison, and is by others extolled as a medicine, and a useful addition to our food.
Tea was originally imported into Europe for medicinal, rather than dietetic, purposes. It was first used in Britain about the year 1666 ; and became a fashionable beverage at court, owing to the example of Katherinc, the queen of Charles II. who had been accustomed to it in Portugal. But it would not probably have come into general use, had not an idea prevailed among medical men, when tea was first introduced into Europe, that health could not be more effectually promoted, than by increasing the fluidity of the blood ; and it was contended, that the infusion of Indian tea was the best means of obtaining that object. It was in the year 1678, that Bontekoe, a Dutch physician, published his celebrated treatise in favor of leaf, to whose authority, its general use in so many parts of Europe, is much to be attributed.
The arguments in favor of tea are many. It is hardly possible to suppose, that such an article as tea, should for ages have been made use of by so many millions of people, as those who are addicted to this beverage in various parts of Asia; and that, notwithstanding the most violent attacks made upon it, from the most respectable authorities that modern medicine can produce J, the practice should be perpetually extended in Europe, unless it were found at least an innocent, and in some respects even an useful article.
The virtues which have been ascribed to tea, are as follow :
1. It is said to be a grateful and useful beverage to persons in health, to take with their solid food; (which is the view with which decorations of it arc used in China); and, in the opinion of many, it ought, for such purposes^ to be preferred to fermented liquors, so general in Europe.
2. There can be no doubt, that it has the property of correcting the pernicious qualities which some wa-» ters possess *.
3. The drinking of tea is said to have the effect of increasing the digestive action of the stomach, an/1 hence is particularly useful in cases of surfeit and indigestion.
4. It also tends to exhilarate the spirits; though this, like every other stimulus, by constant use, loses its effect.
5. The use of tea has been found salutary in medicine. The simple infusion, without sugar or milk, is an excellent diluent and sedative, in ardent fevers; and, as it promotes perspiration, and other secretions, it is frequently drank with advantage in colds, coughs, rheumatism, headaches, &c.
6. Since the introduction of tea, also, complaints of a gravelly nature have greatly diminished.
7. The introduction of tea has certainly done more to promote sobriety, especially among the higher ranks,” than almost any other circumstance. The temptation of the fragrant cup, prepared by a fair hand, induces many to remove to the drawing-room, who would otherwise have remained in the parlor, with their bottle companions.
8. The pleasing occupation which the tea-table furnishes, the beauty of the manufacture in which this preparation of liquid cookery is carried on and circulated, the cheerfulness and lightness of the meal, compared to the solemnity and business-like appearance of a substantial dinner, all tend to make those meals.
The objections which have been urged against the use of tea, are various. It is said, in the first place:
- That the tea-leaf, when fresh from the tree, is of a poisonous nature; and though it loses some of its acrimony, by its being steeped, and afterwords dried, yet, even in the state in which it is sent to this country, it retains much of its narcotic or stupefying qualities.
- There is an astringency in tea, which renders it extremely injurious to the constitution ; and the immoderate use of such an article, must ultimately relax and debilitate *.
- The manner in which it is prepared, by being dried either on iron or on copper plates, must ultimately be extremely injurious. The corrosion of copper are undoubtedly pernicious; those of iron may not perhaps be equally so, yet the effluvia of any steaming metal cannot be favorable to health.
- The manner, also, in which the teas are conveyed to Europe, closely packed up in slight wooden chests, lined with a composition of lead and tin, and exposed to be affected by the corrosion of those two metals, must render the article here much more unwholesome than even in China.
- Not only is the tea itself a pernicious article, but it is often mixed, both in Asia and in Europe, with a variety of other substances of a deleterious quality, with a view, it is said, to improve its color or flavor. Lastly, It is said, that the very mode in which it is consumed in Britain, is more pernicious than in China. According to the eastern method, a small quantity of leaves are boiled in a kettle, with all the water or milk put into-it at once, which is intended to be used at that time. This makes the beverage of an equal strength, and weak at the same time, consequently less injurious: but by our mode of infusing the leaves, with smaller proportions of boiling1 water, the infusion at first is stronger, and its pernicious qualities are increased.
There can be no doubt that tea, if taken in too great a quantity, is a pernicious plant. Perhaps the use of it has partly contributed to the weak bodies, and enervated minds of the Chinese; and it has also tended to injure the general health, and to weaken the strength of those who are tod much addicted to it in Europe f. But as the use of it can
hardly now be abandoned, and as in moderation it may be rendered innocent, as well as palatable, it may be useful to ascertain those rules which ought to be observed in the consumption of this article.
The first rule to be adopted is, to avoid the high-priced and high-flavored teas, which generally owe their flavor to pernicious ingredients, and abound most with those active principles, whence the noxious effects of the article arises, a;>d to prefer those which have been prepared in a simpler manner. The green teas owe their color and flavor, either to the leaves being plucked when young, or to some noxious mode of preparation ; for they disagree with numbers of people, and even a single cup will occasion sickness and other unpleasant symptoms. In a view to wholesome diet, those sorts of tea, the infusions of which are of a dark, and not of a green color, and which go under the general name, of Bohea, are certainly to be preferred ; and if a small quantity of green tea is put in for the? sake of the flavor, by far the greater proportion ought to consist of Bohea, for the sake of health. 2. ft is also of great importance to make the infusion properly; the water should be of the best quality, and in a boiling state when the infusion is made. 3. Only a moderate quantity of tea should be infused. 4. There is nothing more essential, than to have the tea mixed with such ingredients as arc most likely to correct its noxious qualities, particularly with sugar, and a greater proportion of milk or cream used. 5. Tea should be considered, merely as calculated for the purpose of diluting our solid food, and assisting in its digestion. If it were never taken but either with solid nourishment, or soon after it, there is every reason to suppose, that its pernicious effects would, in a great measure, be prevented. But when taken, as it is too often, without solid nourishment, it cannot fail, greatly to injure the tone of the stomach, to undermine the health, and to justify the arguments which have been urged against it.
It is certainly injurious to health, that the first meal we take to recruit the body, after it has long wanted sustenance, when it has suffered by the loss it must have sustained, in consequence of the insensible perspiration of the preceding night; and when it is necessary to prepare for the labours of the succeeding day, should, in general, depend almost entirely upon tea, with a small portion of solid nourishment, more especially if the hour of dinner is distant, and nothing is taken in the interval. Doctor Johnson, therefore, was right in saying, that wherever he dined or slipped, he would choose to breakfast in Scotland; for the Scotch plan, Of eating meat) eggsj and other nourishing substances at breakfast, or what the French call Le dejeuner (i la four* chftte, or fork-breakfast, is a rational system, and ought to be generally adopted, where tea is taken at breakfast.
Citation: pgs 79-80;
Green tea fermentation
Posted by admin in Tea fermentation on May 27th, 2009
For the production of green tea, the fresh leaves are withered in hot pans at a temperature of 160° F. (Chinese method), or steamed (Japanese method); then rolled to break them up and liberate their juices; then ‘fired.’
It will be observed that the chief difference between black and green tea is that the former is fermented, while the latter is not; and one of the main results of fermentation seems to be to render the tannic acid less soluble, so that, as we shall shortly see, an infusion of green tea contains more tannin than an infusion of black.
In former days a good deal of so-called green tea was really made in the same way as black, and subsequently ‘ faced’ with Prussian blue or indigo to give it the proper color; but I am informed that this does not take place now to any important extent.
We have seen that the quality of teas varies with the age of the leaf from which they are prepared, the younger leaves yielding the finest tea. Apart from this cause of variation, teas show marked differences according to the country and district in which they are produced.
Chinese teas have the most delicate flavor of any, but are rather lacking in ‘ body’; they are also devoid of any marked astringency.
Indian teas, and especially those produced in Assam, have the greatest degree of ‘ body’ and astringency. This makes them powerful teas, suited rather for blending with milder varieties than for drinking alone.
Ceylon teas have plenty of body, and a rich and peculiar flavor, but have not so much strength or pungency as the Indian varieties.
According to the district in which they are produced, Chinese black teas may be divided into:
- Monings, from North China, with a small and delicate leaf and a peculiar malty flavor.
- Kaisows, from South China, the so-called red-leaf teas, because the original teas grown in this district had a reddish leaf.
- Oolongs, from Formosa, pungent and slightly bitter, yielding a pale infusion, and chiefly used for purposes of blending.
- Scented orange Pekoe and scented Caper come from the Canton district, and yield a pale, strong infusion with an aromatic flavor, for which reason they are used to give bouquet to blends. Caper is really an un-fermented tea, highly fired, and standing intermediate between the black and green varieties.
Citation: pg 315;