FERMENTATION.
Chemical composition of flour. Yeast—modes of preparing it. Substitutes for it. Fermentation, and its products. Vinous, acetous and putrefactive fermentation.
Having procured good wheat, cleansed it thoroughly, and got it properly ground, and placed in the meal room, the next step is to take a portion of the meal and manufacture it into good bread. But in order that this may be done in the most certain and perfect manner, it is important that the properties of the meal and the principles concerned in bread-making should be well understood.
According to the statement of Prof. Thomson, of Edinburgh, one pound of good wheat meal contains ten ounces of farina or starch, three ounces of bran, six drams of gluten and two drams of sugar;—and it is because wheat contains such proportions of these substances thatit makes the very best loaf bread. The farina or starch is the principal nourishing property;—the saccharine matter or sugar is also highly nutrient; but in the process of making loaf bread, it serves mainly, by its vinous fermentation, to produce the gas or air by which the dough is raised and the bread made light. The gluten is likewise a very nutrient property, but in loaf bread, it principally serves, by its cohesiveness, like gum elastic, or India rubber, to prevent the gas or air formed by the fermentation of the sugar, from escaping or passing off;—and the gas being thus retained, inflates or puffs up the dough, and makes it porous and light. The bran, with its mucilaginous and other properties, not only adds to the nutritiousness of the bread, but eminently serves to increase its digestibility, and to invigorate the digestive organs, and preserve the general integrity of their functions.
The wheat which is raised in Virginia and the southern states generally, contains a larger proportion of gluten than that which is raised in the western part ofthe state of New York. Hence bakers are able to make a larger loaf of bread out of a pound of southern flour than they can out of a pound of western flour; and consequently some of them have endeavored to make their customers believe that the southern flour is the most profitable. It certainlyisthe most profitable for the baker; but it is not the most profitable for the consumer.
The next thing indispensably necessary to the making of good bread, is good lively sweet yeast, or leaven, to produce what is called the panary, or more properly, the vinous fermentation of the saccharine matter, or sugar.
Some bread-makers will do best with one kind of yeast or leaven, and some with another. I have generally found that people do best with those materials to which they have been most accustomed; but I am sorry to find so general a dependence on breweries for yeast. To say nothing of the impure and poisonous substances which brewers employ in the manufacture of beer, and which always affectthe quality of their yeast, I am confident that domestic yeast can be made of a far superior quality. However light and good in other respects that bread may be which is made with brewers yeast, I have rarely if ever seen any in which I could not at once detect the disagreeable properties of the yeast.
There are various ways of making domestic yeast. One of the simplest, and perhaps the best, is the following, which was communicated to me by one of the best bread-makers I ever saw:
“Put into one gallon of water a double handful of hops;—boil them fifteen or twenty minutes, then strain off the water while it is scalding hot;—stir in wheat flour or meal till it becomes a thick batter, so that it will hardly pour;—let it stand till it becomes about blood warm, then add a pint of good lively yeast, and stir it well; and then let it stand in a place where it will be kept at a temperature of about 70° F. till it becomes perfectly light, whether more or less time is required; and then it is fit for use;—or if it is desired to keep aportion of it, let it stand several hours and become cool; and then put it into a clean jug and cork it tight, and place it in the cellar where it will keep cool; and it may be preserved good, ten or twelve days, and even longer.”
Another way by which yeast when thus made may be preserved much longer, and perhaps more conveniently, is, to take it when it has become perfectly light, and stir in good Indian meal until it becomes a hard dough: then take this dough and make it into small thin cakes, and dry them perfectly, without baking or cooking them at all. These cakes, if kept perfectly dry, will be good for several weeks and even months.
When yeast is needed, take some of these cakes (more or less according to the quantity of bread desired) and break them fine and dissolve them in warm water, and then stir in some wheat flour till a batter is formed, which should be kept at a temperature of about 60° F. till the yeast becomes light and lively, and fitted for making bread.
Others, in making this yeast, originally put into the water with the hops, a double handful of good clean wheat bran, and boil them up together and strain off the water as above described: others again, boil up a quantity of wheat bran without the hops, and make their yeast in all other respects as above described.
The milk yeast is greatly preferred by many; and when it is well managed, it certainly makes very handsome bread. The way of making it is simple. Take a quart of milk fresh from the cow, (more or less according to the quantity of bread desired,)—a little salt is generally added, and some add about half a pint of water blood warm, but this is not essential;—then stir wheat flour or meal into the milk till it forms a moderately thick batter; and then cover it over, and place it where it will remain at a temperature of from 60° to 70° F. till it becomes perfectly light. It should then be used immediately: and let it be remembered that dough made with this yeast will sour sooner than that made with other yeast;and also that the bread after it is baked will become extremely dry andcrumblymuch sooner than bread made with other yeast. Yet this bread, when a day old, is exceedingly light and beautiful: albeit some dislike the animal smell and taste which it derives from the milk.
In all these preparations of yeast and dough, it should ever be recollected that “the process of fermentation cannot go on when the temperature is below 30° F., that it proceeds quite slowly at 50°, moderately at 60°, rapidly at 70°, and very rapidly at 80°.”
If, therefore, it is desired to have the yeast or dough stand several hours before it is used or baked, it should be kept at a temperature of about 50°. But in the ordinary way of making bread, a temperature varying from 60° to 70°, or about summer heat, is perhaps as near right as it can well be made.
Prof. Thomson gives the following directions for making yeast in large quantities:—“Add ten pounds of flour to two gallons of boiling water;—stir it well intoa paste, let this mixture stand for seven hours, and then add about a quart of good yeast. In about six or eight hours, this mixture, if kept in a warm place, will have fermented and produced as much yeast as will make 120 quartern loaves” (of 4 lbs. each.)
A much smaller quantity can be made by observing due proportions of the ingredients.
To raise bread in a very short time without yeast, Prof. Thomson gives the following recipe:
“Dissolve in water 2 ounces, 5 drams and 45 grains of common crystallized carbonate of soda, and mix the solution well with your dough, and then add 7 ounces, 2 drams and 22 grains of muriatic acid of the specific gravity of 1,121, and knead it as rapidly as possible with your dough;—it will rise immediately—fully as much, if not more than dough mixed with yeast—and when baked, will be a very light and excellent bread.” Smaller quantities would be required for small batches of bread.
A tea-spoonful or more (according to the quantity of dough or batter) of super-carbonate of soda dissolved in water, and flour stirred in till it becomes a batter, and then an equal quantity of tartaric acid dissolved and stirred in thoroughly, will in a few minutes make very light batter for griddle or pancakes; or if it be mixed into a thick dough, it will make light bread.
Good lively yeast, however, makes better bread than these alkalies and acids: howbeit these are very convenient in emergencies, when bread or cakes must be prepared in a very short time; or when the yeast has proved inefficient.
We see then that wheat meal consists of certain proportions of starch, gluten, sugar, bran, &c.; and that in making loaf bread, we add yeast or leaven, in order to produce that kind of fermentation peculiar to saccharine matter or sugar, which is called vinous, and by which the gas or air is formed that raises the dough. But the sugar is an incorporate part of every particle of the meal, and is therefore equally diffused throughout the whole mass; andhence if we would make the very best loaf bread, the fermentive principle or yeast must also be equally diffused throughout the whole mass, so that a suitable portion of yeast will be brought to act at the same time on every particle of saccharine matter in the mass.
But let us endeavor to understand this process of fermentation. To speak in the language of chemistry, sugar is composed of certain proportions of carbon, oxygen and hydrogen. The yeast, acting on the sugar, overcomes those affinities by which these substances are held in the constitutional arrangement of sugar, and the process of decay or decomposition of the sugar takes place, which is called vinous fermentation. By this process of decay, two other forms of matter are produced, of an essentially different nature from each other and from the sugar. One of them is called carbonic acid gas or air, being formed by a chemical combination of certain proportions of carbon and oxygen. The other is known by the name of alcohol, and consists of a chemical combination of certain proportions of carbon, oxygen, andhydrogen. Carbonic acid gas is also produced by animal respiration or breathing, by the combustion of wood, coal, &c. &c. and in other ways of nature and of art: but neither in nature nor in art is there any known way by which alcohol can be produced, except by that process of the decay or destruction of sugar called vinous fermentation.
The carbonic acid gas, produced in the manner I have stated, is the air which inflates or puffs up and swells out the bread, when there is sufficient gluten or other cohesive matter in the dough to prevent its escape.
If the dough be permitted to stand too long in a warm place, the fermentation, having destroyed most or all of the sugar, will begin to act on the starch and mucilage, and destroy their nature, and produce vinegar; and therefore this stage of it is called the acetous fermentation: and if it still be permitted to go on, it will next commence its work of destruction on the gluten; and this is called the putrefactive fermentation, because it in many respects resembles the putrefaction of animal matter.
The vinous fermentation, therefore, by which the dough is raised and made light, may be carried to all necessary extent, and still be limited in its action to the saccharine matter or sugar—leaving the starch and gluten, and other properties of the meal, uninjured; and this is the point at which the fermentation should be arrested by the heat that bakes the dough. If it be permitted to go beyond the sugar, and act on the mucilage and starch, and produce acidity, the excellence of the bread is in some degree irreparably destroyed. The acid may be neutralized by pearlash or soda, so that the bread shall not be sour; but still, something of the natural flavor of the bread is gone, and it is not possible by any earthly means to restore it; and this injury will always be in proportion to the extent to which the process of the acetous fermentation is permitted to go in destroying the nature of the starch, and the bread will be proportionably destitute of that natural sweetness and delicious richness essential to good bread. Yet it is almost universally true, both in public and domestic bread-making, that the acetousfermentation is allowed to take place; and saleratus, or soda, or some other chemical agent is employed to neutralize the acid. By this means we may have bread free from acidity, it is true, but it is also destitute of the best and most delicious properties of good bread; and generally, by the time it is twenty-four hours old—and this is particularly true of bakers’ bread—it is as dry and tasteless and unsavory as if it were made of plaster of Paris.
Many bread-makers mix their saleratus or soda with their yeast, or introduce it when they mix their dough, so that if the acetous fermentation does take place, the acid is neutralized by the alkali, and therefore, not being perceived, it is supposed never to have existed, and the bread is called sweet and good; especially if a small quantity of molasses be employed in making the dough. Others far more wisely withhold their alkali till the dough is raised enough to mould into the loaf, and then if it is found to be in any degree acid, a solution of saleratus or soda is worked into it, so as just to neutralize the acid, and no more. This is infinitely better that nohave sour bread, which, after all, is almost everywhere met with; yet the very best bread that can be made in this way is only second best. Happy are they who can make good light and sweet bread, without the use of molasses—without suffering the least degree of acetous fermentation to take place, and without employing saleratus, soda, or any other kind of alkali.
The third or putrefactive stage of fermentation rarely takes place in domestic bread-making; but it is by no means uncommon in public bakeries. Indeed it is thought necessary in the manufacture of certain kinds of crackers, in order to make them split open, and render them brittle, and cause them readily to become soft when dipped into water. But dyspepsia crackers, and all other kinds of bread made in this way are, to say the least of them, miserable stuff. For besides the fact that all the best qualities of the flour or meal have been destroyed by fermentation, the great quantity of alkali employed in neutralizing the acid, is necessarily injurious to the digestive organs.