COFFEE

The seeds or berries of the Coffea arabica (Linn.) or coffee plant; a shrub of the natural order Cinch on aceæ, sub-order Coffeæ, indigenous in the low mountainous districts of Arabia Felix, and largely cultivated in various other parts of the world. About 40 millions of pounds of coffee are annually consumed in this country, and the consumption for the whole world has been estimated at about 600 millions of pounds. The seeds are roasted and ground, and used in the form of a decoction or infusion. The term coffee is applied to the prepared beverage as well as to the seeds. The valuable properties of coffee are mainly due to the presence of the alkaloid CAFFEIA or CAFFEINE . Payen gives the following as the composition of the coffee-berry:— | Water | 12·000 | | Woody ti ue | 34·000 | | Fixed fatty matters | 10 to 13·000 | | Gum, sugar, and vegetable acids | 15·500 | | Nitrogenous matter allied to legumin (vegetable casein) | 13·000 | | Free caffein | 0·800 | | Compound of caffein with potash | 3.5 to 5·000 | | Solid fatty e ence | 0·002 | | Aromatic e ential oil | 0·001 | | Saline matters | 6·697 | | ———— | | 100·000 | Prep., . The finest kind of coffee is that called mocha, from Aden, but that in common use is principally supplied from the British plantations in the West Indies. The selection being made, the berries are carefully roasted in revolving cylinders by a gradually applied heat, until the aroma is well developed and the toughne destroyed. Too much heat is avoided, as the volatile and aromatic properties of the coffee, and, consequently, the flavour, are thereby injured; whilst, on the other hand, if the berries are roasted too little, they produce a beverage with a raw, green taste, very liable to induce sickne and vomiting. When properly roasted, coffee has a lively chocolate-brown colour, and should not have lost more than 18% of its weight by the proce . If the lo exceeds 20%, the flavour suffers in proportion. The roasted coffee should be placed in a very dry situation, and excluded from the air as soon as po ible. It loses flavour by keeping, and also powerfully absorbs moisture from the atmosphere by reason of its hygrometric power. Qual., . Coffee promotes digestion, and exhilarates the spirits, and when strong, generally occasions watchfulne , but in some phlegmatic constitutions induces sleep. Drunk in moderation, especially if combined with sugar and milk, it is perhaps the most wholesome beverage known. The various qualities that have been ascribed to it by some persons such as dispelling or causing flatulency, removing dizzine of the head, attenuating the blood, causing biliousne , ., appear to be wholly imaginary. In a medical point of view it has been regarded as a cerebral stimulant and anti-soporific, and as a corrector of opium. As a medicine it should be strong, and is best taken only lukewarm. Adult., . The principal substances used for the purposes of adulteration are caramel, roasted chicory, roasted locust beans, roasted corn, . Chicory being now charged with the same amount of duty as coffee, is not considered in a revenue point of view an adulteration; neverthele , when we contrast coffee with chicory, we at once see the vast superiority of the former over the latter, thus:— Coffee is the fruit of a tree, whilst chicory is the root of an herbaceous plant, and it is well known that more virtues exist in fruits and seeds than in roots. Coffee contains three active principles, viz. an e ential oil, caffeia, and tannic acid, and these exercise a powerful influence on the system, retarding the waste of the ti ues of the body, exciting the brain to increased activity, and exhilarating without intoxicating. Chicory contains none of these constituents. Coffee exerts on the system highly beneficial physiological effects; chicory po e es medicinal properties, which are not desirable in an article of food. Chicory, therefore, is very objectionable, and when a dealer sells a mixture of coffee and chicory for pure coffee, as is almost invariably the case, he is guilty of selling an adulterated article, and ought to be punished accordingly. The adulteration with caramel or chicory may readily be detected as follows:— 1. A spoonful of pure coffee placed gently on the surface of a gla of cold water will float for some time, and scarcely colour the liquid; if it contains caramel or chicory, it will rapidly absorb the water, and, sinking to the bottom of the gla , communicate a reddish-brown tint as it falls. Another method of applying this test is by expertly shaking a spoonful of the suspected coffee with a wine-gla ful of cold water, and then placing the gla upon the table. If it is pure, it will rise to the surface, and scarcely colour the liquid; but if caramel or chicory is present, it will sink to the bottom, and the water will be tinged of a deep red as before. 2. The brown colour of decoction or infusion of roasted coffee becomes greenish when treated with a per-salt of iron; and a brownish-green, flocculent precipitate is formed. The colour of chicory is only deepened, but not otherwise altered, and no precipitate is formed, under the same treatment. A mixture of chicory and coffee retains a brownish-yellow colour after the precipitate has subsided, and the liquid appears brownish yellow by refracted light. The addition of a little weak ammonia water aids the subsidence of the precipitate. IMG:596405606043057898_i498-2.png: 3. Under the microscope (see Chicory ) the presence of chicory may be readily detected by the size, form, and ready separation of the cells of the cellular ti ue, and by the presence and abundance of the pitted ti ue or dotted ducts, which are absent from coffee, and by the size of the spiral ve els, which are very small in coffee. The most characteristic structure, however, and that by which chicory can be easily identified, is the lactiferous ti ue. Roasted corn, and other amylaceous substances, may also be detected, in the same way, by the peculiar size and character of their starch grains. Under the microscope the berry is seen to consist of a hard, tough ti ue, that resists even long soaking. The testa covering the berry is made of lengthened cells with oblique markings resting on a thin membrane, almost structurele . These oblique markings of the cells are so characteristic as to render the cells distinguishable from every other ti ue. The substance of the berry consists of angular cells, each one of which contains minute drops of oil. This oil is in some measure driven off during the proce of roasting, which, however, leaves the structure unimpaired where it is not charred. IMG:596405606043057898_i498-1.png: Roasted corn, beans, ., may be detected by the cold decoction striking a blue colour with tincture of iodine. Pure coffee is merely deepened a little in colour by this substance. 4. (A. H. Allen.) The amount of ash in genuine coffee does not exceed 4·5 per cent.; chicory yields 5 per cent. The silica in coffee ash never exceeds 1 per cent., while in chicory it varies from 10-36 per cent. The average soluble ash in coffee is 3·24, while in chicory it is 1·74 per cent. By determining the soluble ash S, the per-centage of pure coffee C may be calculated thus:— (100 S - 174) C = 2 —————— 3 The density of coffee-infusion is determined by heating the powder with 10 times its weight of cold water, raising the liquid to the boiling point, filtering, and taking the gravity at 15·5° C. Taking the density of pure coffee-infusion at 1008·6, and that of chicory at 1020·6, the per-centage of pure coffee C in the sample may be calculated from the equation 100(1020 - D) C = —————— 12 where D represents the density of the infused sample. The relative tinctorial power of an infusion of a sample of coffee is determined by boiling a given weight with 20 c. c. of water for a few minutes, filtering, and again boiling the residue until thoroughly exhausted. An equal weight of a standard mixture of equal weights of pure coffee and chicory is treated in a precisely similar manner. The standard solution is made up to 200 c. c., that of the sample to 100 c. c.; 10 c. c. of the latter are put into a narrow burette, and some of the standard into a test tube of exactly equal bore. If the tints are exactly the same, the sample consisted of pure coffee; if chicory is present, water must be added to the sample until the tints are the same. Each c. c. of water represents 5 per cent. of chicory. The presence of leguminous seeds or cereals may be detected by boiling the sample with animal charcoal and water, filtering, and testing for starch in the cold liquid with iodine. Neither coffee nor chicory contains starch. Obs. A few years ago the attention of the scientific world was drawn to the value of roasted coffee leaves, as furnishing materials for a beverage unexcelled in excellence by the coffee berry itself. It appears that the leaves, prepared for use, may be purchased for 1 1 ⁄ 2 d. per lb., or packed ready for export at 2d. per lb. “That this preparation contains a considerable amount of the nutritious principles of coffee is evident from the analysis; but as the leaves can only be collected in a good state at the expense of the coffee-bush, it is doubtful whether the coffees is the best.” (Jury Report, Exhibition, 1851.) Coffee for the table is best prepared with the aid of a French cafetière, or coffee biggin, furnished with a percolator or strainer, which will permit a moderately rapid filtration. To produce this beverage in perfection, it is nece ary to employ the best materials in its preparation—fresh roasted and fresh ground. “At least 1 oz. of coffee should be used to make 3 common-sized coffee-cupfuls, with 1 teaspoonful of freshly roasted and ground chicory. If desired strong, the quantity of both should be doubled.” (Cooley.) Many habitual coffee drinkers cannot tolerate the use of chicory, which is a doubtful improver of coffee. The prevailing fault of the coffee made in England is its want of strength and flavour. The coffee-pot should be heated previously to putting in the coffee, which may be done by means of a little boiling water. The common practice of boiling coffee is quite unnece ary, for all its flavour and aroma is readily extracted by boiling hot water. Indeed, all the “useful and agreeable matter in coffee is very soluble, it comes off with the first waters of infusion, and needs no boiling.” (Ure.) Should prejudice, however, induce the housewife or cook to boil her coffee, it should be only just simmered for a minute, as long or violent boiling injures it considerably. When coffee is prepared in a common pot, the latter being first made hot, the boiling water should be poured over the powder, and not, as is commonly the plan, put in first. It should then be kept stirred for 4 or 5 minutes, when a cup should be poured out and returned again, and this operation repeated 3 or 4 times, after which, if allowed to repose for a few minutes, it will generally become fine of itself. In all cases, where a percolator is not used, the liquor should be well stirred up several times before finally covering it up to settle for use. Amongst the various descriptions of coffee pots in use we may mention those of French make, consisting of two cylindrical ve els, the upper having a metal strainer, on which the ground coffee is placed, and through which the clear infusion runs into the lower one; Loysell’s—an apparatus making very good coffee, and as one of the latest, an ingenious and inexpensive coffee pot, known as the “Kaffee Kanne,” devised by Mr Ash, of Oxford Street. Ash’s “Kaffee Kanne” consists of an ordinary biggin, surrounded by a jacket containing boiling water. The coffee is made by percolation in the inner ve el, and being kept at the point of ebullition by the surrounding boiling water, yields a beverage of excellent flavour and aroma. Coffee is sometimes clarified by adding a shred of isingla , a small piece of clean eel or sole-skin, or a spoonful of white of egg. An excellent plan, common in France, is to place the ve el containing the made coffee upon the hearth, and to sprinkle over its surface half a cupful of cold water, which from its greater gravity descends, and carries the ‘foulne ’ with it. Another plan sometimes adopted is to wrap a cloth, previously dipped into cold water, round the coffee-pot. This method is commonly practised by the Arabians in the neighbourhood of Yemen and Moka, and rapidly clarifies the liquor, unle a very large quantity of chicory is present. It should be recollected that the use of isingla , white of egg, and all like artificial finings, remove much of the astringency and vivacity of the liquor. The French, who are remarkable for the superior quality of their coffee, generally allow an ounce to each large coffee-cupful of water, and they use the coffee both newly ground and freshly roasted. A shred of saffron, or a little vanilla, is frequently added, whilst the percolating coffee-pot is generally employed. When the Paris i an uses a common coffee-pot he generally divides the water into 2 parts. The first portion he pours on boiling hot, and allows it to infuse for 4 or 5 minutes; he then pours this off as clear as po ible, and boils the grounds for 2 or 3 minutes with the remaining half of the water. As soon as this has deposited the sediment it is decanted, and mixed with the infusion. The object of this proce is to obtain the whole of the strength as well as the flavour. The infusion is thought to contain the latter, and the decoction the former; a plausible, but erroneous idea, since both of them were carried off by the first water. A much better method, and one we can recommend from experience, is to divide the coffee into 2 parts. Boil the first portion in the coffee-pot for 4 or 5 minutes, then add the other portion, and allow it to infuse slowly for about 10 minutes, the coffee-pot lid being kept well closed. This gives a coffee po e ing a flavour which even the French cannot excel.