CHAPTER XI. OVENS ANCIENT AND MODERN.
发布时间:2020-06-24 作者: 奈特英语
We have now got the loaf made, and the next thing is to bake it; for the home-baked loaf, the oven of a kitchener or gas stove will do very well, and the heat should be about 400 deg. Fahr. A baker’s oven is a thing per se. For hundreds of years they were made on the same old pattern, but now, except in many of the small underground bakeries, they are scientifically built, fitted with pyrometers, and with internal lamps. Mr. Austin writes thus of the oven:
‘The baker’s oven is generally a brick oven, heated thoroughly with coal or wood according to construction; if made for coal, the damper will be on the one side and the furnace on the other, so that the flames play all round the oven; if constructed for wood, it must be heated with a good solid heat, with wood burnt in the interior of the oven, and then well cleaned out with a scuffle. As to the degrees of heat of the oven the laborious explanations and number of them may be reduced to three—viz., sharp or “flash,” as named in recipes; the second degree, moderate or “solid,” as used for large or solid articles, as wedding cakes, &c.; then slack or cool.
‘The baker’s old-fashioned method of testing the temperature of his oven is instructive. He throws flour on the floor. If it blackens without taking fire137 the heat is sufficient. It might be supposed that this is too high a temperature, as the object is to cook the bread, not to burn it; but we must remember that the flour which has been prepared for baking is mixed with water, and the evaporation of this water will materially lower the temperature of the dough itself. Besides this, we must bear in mind that another object is to be attained. A hard shell or crust has been formed, which will so encase and support the lump of dough as to prevent it from subsiding when the further evolution, carbonic gas, shall cease, which will be the case some time before the cooking of the mass is completed. It will happen when the temperature reaches the point at which the yeast cells can no longer germinate, when the temperature is below the boiling point of water.
‘In spite of all this outside temperature, that of the inner part of the loaf is kept down to a little above 212 degrees by the evaporation of the water contained in the bread; the escape of this vapour and the expansion of carbonic acid bubbles by heat increasing the porosity of the loaf. The outside being heated considerably above the temperature of the inner part, this variation produces the difference between the crust and the crumb. The action of the high temperature indirectly converting some of the starch into dextrin will be understood from what is already stated, and also the partial conversion of this dextrin into caramel. Thus we have in the crust an excess of dextrin as compared with the crumb, and the addition of a variable quantity of caramel. In lightly baked bread, with the crust of uniform pale yellowish colour,138 the conversion of the dextrin into caramel has barely commenced, and the gummy character of the dextrin coating is well displayed. So much bread, especially the long staves of life common in France, appears as though they had been varnished, and their crust is partially soluble in water. This explains the apparent paradox that hard crust or dry toast is more easily digested than the soft crumb of bread, the cookery of the crumb not having been carried beyond the mere hydration of the gluten and the starch and such degree of dextrin formation as was due to the action of the diastaste of grain during the preliminary period of “rising.”’
A form of oven now much in vogue is borrowed from Vienna. It is built of stone or brick; the roof is very low, and the floor slopes upwards towards the far end. The effect of this form of construction is to drive the steam rising from the loaves down on to the top of them again, thereby giving them the glazed surface so much admired in foreign bread. Steam is sometimes driven in with the same object; being lighter than that rising from the bread, it drives the latter down. The ovens are heated from below. Loaves remain in for one and a half or two hours.
As in everything connected with baking, during the past few years great improvements have been made in bakers’ ovens. Science has been brought to bear upon them, and we now have them heated by gas or steam in addition to coal and coke, besides improved alterations in many ways.
Nor do modern improvements in baking appliances stop short at ovens. Most bakers doing a good139 business use kneading machines, of which there are many in the market. With one exception—that of the Adair mixer, which has no arms nor beaters, but simply rotates, and by this action the flour and water pass through the rods of iron, which are placed crosswise in the machine, and become perfectly and proportionately mixed—they are all, more or less, on the same principle, of revolving arms, blades, or knives by which the flour and water are properly mixed, and the position of the dough being perpetually changed, it is effectually kneaded without the objectionable intervention of manual labour.
The earliest kneading machine that I can find mentioned is in 1850, when the illustrious philosopher, Arago, presented and recommended to the Institute of France the kneading and baking apparatus of M. Rolland, then a humble baker of the Twelfth Arrondissement. The kneading machine was described as exceedingly simple, and capable of being worked, when under a full charge, by a young man from 15 to 20 years old, the necessity for horse labour or steam power being thus obviated; and it was claimed that in less than twenty minutes a sack of flour could be converted into a perfect homogeneous and a?rated dough altogether superior to any dough that could be obtained by manual kneading.
Another attempted improvement in the manufacture of bread was a?rating the dough without using any ferment, such as yeast, etc., and this has been accomplished by means of mixing hydrochloric acid and carbonate of soda with the dough, or using bicarbonate of ammonia, or forcing carbonic acid into140 the water with which the flour is mixed. The latter is called the Dauglish system, from its inventor, the late John Dauglish, M.D. (born 1824, died January 14, 1866), and it is now in full working operation.
By this system carbonic acid gas is generated as if for making soda water, and, supposing a sack of flour was to be converted into dough, the following would be the treatment: A lid at the top of the mixer is opened, and the flour passed down into it through a spout from the floor above. The lid of the mixer is then fitted tightly on, and the air within it exhausted by the pump. The requisite quantity of water, about 17 gallons, is drawn into the water vessel, and carbonic acid is forced into it till the pressure amounts to from 15lb. to 25lb. per square inch. The a?rated water is then passed into the mixer, and the mixing arms are set in motion, by which, in about seven minutes, the flour and water are incorporated into a perfectly uniform paste. At the lower end of the mixer a cavity is arranged, gauged to hold sufficient dough for a 2lb. loaf, and by a turn of a lever that quantity is dropped into a pan ready for at once depositing in the oven. The whole of the operations can be performed in less than half an hour.
The advantages of this system are absolute purity and cleanliness, but it is simply porous dough, and has not got the flavour of fermented bread. The plant, too, is very expensive, which renders it impossible for the ordinary baker to adopt it.
Certainly, machinery has been applied with very great advantage to the manufacture of another kind of bread, on which they that go down upon the sea141 in ships were wont to depend—namely, ship’s biscuits. Badly made of bad materials, and ofttimes full of weevils were they, so hard that they had to be soaked in some liquid before they could be eaten, or else broken up and boiled with the pea soup.
Up to the year 1833 the ships of the Royal Navy were supplied with biscuits made at Gosport by gangs of five men, severally named the furner, the mate, the driver, the brakeman, and the idleman. The driver made the dough in a trough with his naked arms. The rough dough was then placed on a wooden platform, to be worked by the brakeman, who kneaded it by riding and jumping on it. Then it was taken to a moulding board, cut into slips, moulded by hand, docked, or pierced full of holes, and pitched into the oven by the joint action of the gang. The nine ovens in the Royal Clarence Victualling Yard required the labour of 45 men to keep them in full operation, and the product was about 14cwt. of biscuit per hour, at a cost for labour and utensils of 1s. 7d. per cwt. This system was superseded by machinery, and biscuits have been for many years past produced with almost incredible rapidity, perfect in kneading, moulding, and baking, and at a cost for labour and utensils of less than a third of the old outlay.
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