Popular Science Monthly/Volume 26/March 1885/The Chemistry of Cookery XXI
|THE CHEMISTRY OF COOKERY.|
THE reader will understand, from what has already been stated concerning the origin of the difference between natural sweet wines and natural dry wines, that the conversion of either one into the other is not a difficult problem. Wine is a fashionable beverage in this country, and fashions fluctuate. These fluctuations are not accompanied with a corresponding variation in the chemical composition of any particular class of grapes, but somehow the wine produced therefrom obeys the laws of supply and demand. For some years past the demand for dry sherry has dominated in this country, though, as I am informed, the weathercock of fashion is now on the turn.
One mode of satisfying this demand for dry wine is, of course, to select a grape which has less sugar and more albuminous matter, but in a given district this is not always possible. Another is to gather the grapes before they are fully ripened, but this involves a sacrifice in the yield of alcohol, and probably of flavor. Another method, obvious enough to the chemist, is to add as much albuminous or nitrogenous material as shall continue to feed the yeast-fungus until all, or nearly all, the sugar in the grape shall be converted into alcohol, thus supplying strength and dryness (or salinity) simultaneously. Should these be excessive, the remedy is simple and cheap wherever water abounds. It should be noted that the quantity of sugar naturally contained in the ripe grape varies from ten to thirty per cent—a very large range. The quantity of alcohol varies proportionally when the must is fermented to dryness. According to Pavy, "there are dry sherries to be met with that are free from sugar," while in other wines the quantity of remaining sugar amounts to as much as twenty per cent.
White of egg and gelatine are the most easily available and innocent forms of nitrogenous material that may be used for sustaining or renewing the fermentation of wines that are to be artificially dried. My inquiries in the trade lead me to conclude that this is not understood as well as it should be. Both white of egg and gelatine (in the form of isinglass or otherwise) are freely used for fining, and it is well enough known that wines that have been freely subjected to such fining keep better and become drier with age, but I have never yet met a wine-merchant who understood why, nor any sound explanation of the fact in the trade literature. When thus added to the wine already fermented, the effect is doubtless due to the promotion of a slow, secondary fermentation. The bulk of the gelatine or albumen is carried down with the sediment, but some remains in solution. There may be some doubt as to the albumen thus remaining, but none concerning the gelatine, which is freely soluble both in water and alcohol. The truly scientific mode of applying this principle would be to add the nitrogenous material to the must.
I dwell thus upon this, because, if fashion insists so imperatively upon dryness as to compel artificial drying, this method is the least objectionable, being a close imitation of natural drying, almost identical; while there are other methods of inducing fictitious dryness that are mischievous adulterations.
Generally described, these consist in producing an imitation of the natural salinity of the dry wine by the addition of factitious salts and fortifying with alcohol. The sugar remains, but is disguised thereby. It was a wine thus treated that first brought the subject of the sulphates, already referred to, under my notice. This, although sold to my friend at a good price, was a concoction of the character known in the trade as Hambro' sherry. It contained a considerable quantity of sugar, but was not perceptibly sweet. It was very strong and decidedly acid; contained free sulphuric acid and alum, which, as all who have tasted it know, gives a peculiar sense of dryness to the palate.
The sulphuring, plastering, and use of Spanish earth, described in my last, increase the dryness of a given wine by adding mineral acid, and mineral salts. In a paper recently read before the French Academy by L. Magnier de la Source ("Comptes Rendus," vol. xcviii, page 110), the author states that "plastering modifies the chemical characters of the coloring-matter of the wine, and not only does the calcium sulphate decompose the potassium hydrogen tartrate, with formation of calcium tartrate, potassium sulphate, and free tartaric acid, but it also decomposes the neutral organic compounds of potassium which exist in the juice of the grape." I quote from abstract in "Journal of of the Chemical Society" of May, 1884.
In the French "Journal of Pharmaceutical Chemistry," vol. vi, pp. 118-123 (1882), is another paper, by P. Carles, in which the chemical and hygienic results of plastering are discussed. His general conclusion is that the use of gypsum in clearing wines "renders them hurtful as beverages"; that the gypsum acts "on the potassium bitartrate in the juice of the grape, forming calcium tartrate, tartaric acid, and potassium sulphate, a large proportion of the last two bodies remaining in the wine." Unplastered wines contain about two grammes of free acid per litre; after plastering, they contain "double or treble that amount, and even more."
A German chemist, Griessmayer, and, more recently, another. Kaiser, have also studied this subject, and arrive at similar conclusions. Kaiser analyzed wines which were plastered by adding gypsum to the must, that is to the juice before fermentation, and also samples in which the gypsum was added to the "finished wine," i. e., for fining, so called. He found that "in the finished wine, by the addition of gypsum, the tartaric acid is replaced by sulphuric acid, and there is a perceptible increase in the calcium; the other constituents remain unaltered." His conclusion is, that the plastering of wine should be called adulteration, and treated accordingly, on the ground that the article in question is thereby deprived of its characteristic constituents, and others, not normally present, are introduced. This refers more especially to the plastering or gypsum fining of finished wines (Biedermann's "Centralblatt," 1881, pp. 632, 633).
In the paper above named, by P. Carles, we are told that, "owing to the injurious nature of the impurities of plastered wines, endeavors have been made to free them from these by a method called 'deplastering,' but the remedy proves worse than the defect." The samples analyzed by Carles contained barium salts, barium chloride having been used to remove the sulphuric acid. In some cases excess of the barium salt was found in the wine, and in others barium sulphate was held in suspension.
Closely following the abstract of this paper, in the "Journal of the Chemical Society, is another from the French "Journal of Pharmaceutical Chemistry," vol. v, pp. 581-583, to which I now refer, by the-way, for the instruction of claret-drinkers, who may not be aware of the fact that the phylloxera destroyed all the claret grapes in certain districts of France, without stopping the manufacture or diminishing the export of claret itself! In this paper, by J. Lefort, we are told, as a matter of course, that "owing to the ravages of the phylloxera among the vines, substitutes for grape-juice are being introduced for the manufacture of wines; of these, the author specially condemns the use of beet-root sugar, since, during its fermentation, besides ethyl, alcohol, and aldehyde, it yields propyl, butyl, and amyl alcohols, which have been shown by Dujardin and Audigé to act as poisons in very small quantities." In connection with this subject I may add that the French Government carefully protects its own citizens by rigid inspection and analysis of the wines offered for sale to French wine-drinkers; but does not feel bound to expend its funds and energies in hampering commerce by severe examination of the wines that are exported to "John Bull et son Île," especially as John Bull is known to have a robust constitution. Thus, vast quantities of brilliantly-colored liquid, flavored with orris-root, which would not be allowed to pass the barriers of Paris, but must go somewhere, is drunk in England at a cost of four times as much as the Frenchman pays for genuine grape-wine. The colored concoction being brighter, and skillfully cooked, and duly labeled to imitate the products of real or imaginary celebrated vineyards, is preferred by the English gourmet to anything that can be made from simple grape-juice.
I should add that a character somewhat similar to that of natural dryness is obtained by mixing with the grape-juice wine a secondary product, obtained by adding water to the marc—i. e., the residue of skins, etc., that remains after pressing out the must or juice; a minimum of sugar is dissolved in the water, and this liquor is fermented. The skins and seeds contain much tannic acid or astringent matter, and this roughness imposes upon many wine-drinkers, provided the price charged for the wine thus cheapened be sufficiently high. After this, according to Gardner (Churchill's "Technological Handbook," "The Brewer, Distiller, and Wine Manufacturer"), "the same marc is treated in a similar manner with a fresh quantity of sugar solution, and sometimes undergoes as many as three or four separate macerations, each successive infusion occupying a rather longer time. It will be easily understood that wine thus prepared costs less than very small Leer, though its retail selling price may be regulated by the "étiquette" or label (from which I suppose our word ticket is derived) that is finally pasted on the bottles.
The special bouquets and curious flavors demanded by connoisseurs can be more easily added to mixtures largely composed of these second and third runnings than to simple grape-juice having its own grape-flavor, just as the juniper-flavor is more easily added to "silent spirit" than to whisky or cognac. We may thus obtain a clew to the mysterious fact that the market is well supplied with wines bearing the names of celebrated vineyards, of which the whole produce is bought by special contract by certain Continental potentates. Many of these chateau vineyards are so small that they can not actually produce one tenth of the wine that is commercially derived from them.
Some years ago, while resident in Birmingham, an enterprising manufacturing druggist consulted me on a practical difficulty which he was unable to solve. lie had succeeded in producing a very tine claret (Château Digbeth, let us call it) by duly fortifying with silent spirit a solution of cream of tartar, and flavoring this with a small quantity of orris-root. Tasted in the dark, it was all that could be desired for introducing a new industry to Birmingham; but the wine was white, and every coloring material that he had tried, producing the required tint, marred the flavor and bouquet of the pure Château Digbeth. He might have used one of the magenta dyes, but as these were prepared by boiling aniline over dry arsenic acid, and my Birmingham friend was burdened with a conscience, he refrained from thus applying one of the recent triumphs of chemical science.
This was 1 magenta is sufficient to give the paper a violet shade, while a larger quantity produces a carmine red. "With genuine red wine the color produced is a grayish blue, which becomes lead-colored on drying. I copy the above from the "Quarterly Journal of Science" of April, 1877. The editor adds that the inventors of this paper have discovered a method of removing the magenta from wines without injuring their quality, "a fact of some importance, if it be true that several hundred thousand hectolitres of wine sophisticated with magenta are in the hands of the wine-merchants" (a hectolitre is equal to twenty-two gallons).to the invasion of France by the phylloxera. During the early period of that visitation, French enterprise being more powerfully stimulated and less scrupulous than that of Birmingham, made use of the aniline dyes for coloring spurious claret to such an extent that the French Government interfered, and a special test paper, named Œnokrine, was invented by MM. Lainville and Roy, and sold in Paris, for the purpose of detecting falsely-colored wines. The mode of using the Œnokrine was as follows: "A slip of the paper is steeped in pure wine for about five seconds, briskly shaken, in order to remove excess of liquid, and then placed on a sheet of white paper, to serve as a standard. A second slip of the test-paper is then steeped in the suspected wine in the same manner, and laid beside the former. It is asserted that
Another simple test, that was recommended at the time, was to immerse a small wisp of raw silk in the suspected wine, keeping it there at a boiling heat for a few minutes. Aniline colors dye the silk permanently; the natural color of the grape is easily washed out. I find, on referring to the "Chemical News," the "Journal of the Chemical Society," the "Comptes Rendus," and other scientific periodicals of the period of the phylloxera-plague, such a multitude of methods for testing false-coloring materials that I give up in despair my original intention of describing them in this paper. It would demand far more space than the subject deserves. I will, however, just name a few of the more harmless coloring adulterants that are stated to have been used, and for which special tests have been devised by French and German chemists.
Beet-root, peach-wood, elderberries, mulberries, logwood, privet-berries, litmus, ammoniacal cochineal, Fernambucca-wood, phytolacca, burned sugar, extract of rhatany, bilberries; "jerupiga" or "geropiga," a "compound of elder-juice, brown sugar, grape-juice, and crude Portuguese brandy" (for choice tawny port); "tincture of saffron, turmeric, or safflower" (for golden sherry); red poppies, mallow flowers, etc.
Those of my readers who have done anything in practical chemistry are well acquainted with blue and red litmus, and the general fact that such vegetable colors change from blue to red when exposed to an acid, and return to blue when the acid is overcome by an alkali. The coloring-matter of the grape is one of these. Mulder and Maumené have given it the name of œnocyan or wine-blue, as its color, when neutral, is blue; the red color of genuine wines is due to the presence of tartaric and acetic acid acting upon the wine-blue. There are a few purple wines, their color being due to unusual absence of acid. The original vintage, which gave celebrity to port wine, is an example of this.
The bouquet of wine is usually described as due to the presence of ether, œenanthic ether, which is naturally formed during the fermentation of grape-juice, and is itself a variable mixture of other ethers, such as caprilic, caproic, etc. The oil of the seed of the grape contributes to the bouquet. The fancy values of fancy wines are largely due, or, more properly speaking, were largely due, to peculiarities of bouquet. These peculiar wines became costly because their supply was limited, only a certain vineyard, in some cases of very small area, producing the whole crop of the fancy article. The high price once established, and the demand far exceeding the possibilities of supply from the original source, other and resembling wines are sold under the name of the celebrated locality, with the bouquet or a bouquet artificially introduced. It has thus come about, in the ordinary course of business, that the dearest wines of the choicest brands are those which are the most likely to be sophisticated. The flavoring of wine, the imparting of delicate bouquet, is a high art, and is costly. It is only upon high-priced wines that such costly operations can be practiced. Simple ordinary grape-juice—as I have already stated—is so cheap when and where its quality is the highest, i. e., in good seasons and suitable climates, that adulteration with anything but water renders the adulterated product more costly than the genuine. When there is a good vintage it does not pay even to add sugar and water to the marc or residue, and press this a second time. It is more profitable to use it for making inferior brandy, or wine-oil, huile de marc or even for fodder or manure.
This, however, only applies where the demand is for simple genuine wine, a demand almost unknown in England, where connoisseurs abound who pass their glasses horizontally under their noses, hold them up to the light to look for beeswings and absurd transparency, knowingly examine the brand on the cork, and otherwise offer themselves as willing dupes, to be pecuniarily immolated on the great high altar of the holy shrine of costly humbug.
Some years ago I was at Frankfort, on my way to the Tyrol and Venice, and there saw, at a few paces before me, an unquestionable Englishman, with an ill-slung knapsack. I spoke to him, earned his gratitude at once by showing him how to dispense with that knapsack abomination, the breast-strap. We chummed, and put up at a genuine German hostelry of my selection, the Gasthaus zum Schwanen. Here we supped with a multitude of natives, to the great amusement of my new friend, who had hitherto halted at hotels devised for Englishmen. The handmaiden served us with wine in tumblers, and we both pronounced it excellent. My new friend was enthusiastic; the bouquet was superior to anything he had ever met with before, and if it could only be fined—it was not by any means bright—it would be invaluable. He then took me into his confidence. He was in the wine-trade, assisting in his father's business; the "governor" had told him to look out in the course of his travels, as there were obscure vineyards here and there, producing very choice wines, that might be contracted for at very low prices. This was one of them; here was good business. If I would help him to learn all about it, presentation cases of wine should be poured upon me forever after.
I accordingly asked the handmaiden, "Was für Wein?" etc. Her answer was, "Apfel Wein." She was frightened at my burst of laughter, and the young wine-merchant also imagined that he had made acquaintance with a lunatic, until I translated the answer, and told him that we had been drinking cider. We called for more, and recognized the "curious" bouquet at once.
The manufacture of bouquets has made great progress of late, and they are much cheaper than formerly. Their chief source is coal-tar, the refuse from gas-works. That most easily produced is the essence of bitter-almonds, which supplies a "nutty" flavor and bouquet. An}-body may make it by simply adding benzole (the most volatile portion of the coal-tar), in small portions at a time, to warm, fuming nitric acid. On cooling and diluting the mixture, a yellow oil, which solidifies at a little above the freezing-point of water, is formed. It may be purified by washing first with water, and then with a weak solution of carbonate of soda to remove the excess of acid. It is now largely used in flavoring as essence of bitter-almonds. Its old perfumery name was essence of mirbane.
By more elaborate operations on the coal-tar product, a number of other essences and bouquets of curiously imitative character are produced; one of the most familiar of these is the essence of jargonelle pears, which flavors the "pear-drops" of the confectioner so cunningly; another is raspberry flavor, by the aid of which a mixture of fig-seeds and apple-pulp, duly colored, may be converted into a raspberry jam that would deceive our prime minister. I do not say that it now is so used, though I believe it has been, for the simple reason that wholesale jam-makers now grow their own fruit so cheaply that the genuine article costs no more than the sham. Raspberries can be grown and gathered at a cost of about twopence per pound.
With wine at sixty shillings to one hundred shillings per dozen the case is different. This price leaves an ample margin for the conversion of "Italian reds," Catalans, and other sound, ordinary wines into any fancy brands that may happen to be in fashion. Such being the case, the mere fact that certain emperors or potentates have bought up the whole produce of the château that is named on the labels does not interfere with the market supply, which is strictly regulated by the demand.
Visiting a friend in the trade, he offered me a glass of the wine that he drank himself when at home, and supplied to his own family. He asked my opinion of it. I told him that I thought it was genuine grape-juice, resembling that which I had been accustomed to drink at country inns in the Coté d'Or (Burgundy) and in Italy. He told me that he imported it directly from a district near to that I first named, and could supply it at twelve shillings per dozen, with a fair profit. Afterward, when calling at his place of business in the West End, he told me that one of his best customers had just been tasting the various dinner-wines then remaining on the table, some of them expensive, and that he had chosen the same as I had; but what was my friend to do? Had he quoted twelve shillings per dozen, he would have lost one of his best customers, and sacrificed his reputation as a high-class wine-merchant; therefore he quoted fifty-four shillings, and both buyer and seller were perfectly satisfied: the wine-merchant made a large profit, and the customer obtained what he demanded—a good wine at a "respectable price." He could not insult his friends by putting cheap twelve-shilling trash on his table!
Here arises an ethical question. Was the wine-merchant justified in making this charge under the circumstances; or, otherwise stated, who was to blame for the crookedness of the transaction? I say the customer; my verdict is, "him right!"
In reference to wines, and still more to cigars, and some other useless luxuries, the typical Englishman is a victim to a prevalent commercial superstition. He blindly assumes that price must necessarily represent quality, and therefore shuts his eyes and opens his mouth to swallow anything with complete satisfaction, provided that he pays a good price for it at a respectable establishment, i. e., one where only high-priced articles are sold.
If any reader thinks I speak too strongly, let him ascertain the market price per pound of the best Havana tobacco-leaves where they are grown, also the cost of twisting them into cigar-shape (a skillful workman can make a thousand in a day), then add to the sum of these the cost of packing, carriage, and duty. He will be rather astonished at the result of this arithmetical problem.
If these things were necessaries of life^ or contributed in any degree or manner to human welfare, I should protest indignantly; but seeing what they are, and what they do, I rather rejoice at the limitation of consumption effected by their fancy prices.
- The wine-trade has two rival magazines, both very high-priced, exclusively devoted to its interests, besides others that arc partially so.