M OTHER AMBROISINE was making bread. Standing in front of the kneading-trough, her cheeks glowing with the exercise, her sleeves rolled up to her elbows, alternately she thrust her closed fists into the mass of dough, which yielded with a dull flic-flac, then, lifting in both hands ponderous sheets of it, she let them fall back heavily into the trough. Marie, standing on a little stool so as to bring herself on a level with the trough, lent what aid she could in this rather arduous task. After sufficient kneading the dough was cut into a number of pieces, each of them destined to become a loaf of bread, and these were put into little straw baskets and covered with woolen cloths so that a gentle heat might finish the work already begun.
Before the loaves had risen enough for baking, Uncle Paul gathered the children around him and told them some interesting facts about bread-making.
"If the flour were merely mixed with water," he began, "and the dough were then put into the oven in that condition, the result would be nothing but a dense, heavy loaf, a sort of hard pancake, repulsive to the stomach on account of its indigestibility. Bread, to be easily digested, must be full of countless little holes, like a sponge; it must have those myriad eyes that help to crumble the loaf and aid the final process of subdivision which it is the stomach's part to perform. A prolonged diet of bread made simply of flour and water is so far from appetizing that it was imposed as a penance by the Israelites in one of their sacred festivals. When they set out from Egypt, led by Moses, they had not time in their hasty departure to prepare bread in the ordinary manner, and so they cooked in the ashes cakes called unleavened bread, that is to say bread without any leaven or yeast. In commemoration of this even the Jews of our own day eat unleavened bread at the celebration of their Feast of the Passover. This bread consists of thin cakes, compact and hard, of which a few mouthfuls are not unpleasant, but if one eats nothing else for several days the stomach is left unsatisfied. It is by a fermentation similar to that of must in wine-making that flour is made into bread, real bread, the most highly prized of all foods and the one we never tire of.
"Flour contains, as I have already told you, first starch and gluten, and then a small quantity of sugar as proved by the slightly sweet taste of a pinch of flour on the tongue. Now this tiny proportion of sugar is precisely the substance that causes fermentation in dough; that is to say, it decomposes and forms alcohol and carbonic acid gas, as in the making of wine."
"Bread and wine, then," said Marie, "are something alike in the way they are made."
"It is more than a likeness: it is a perfect sameness so far as concerns the decomposition of sugar into carbonic acid gas and alcohol; and it is, finally, a sameness in respect to fermentation. The dough of which bread is made ferments just as does the must that is to become wine.
"It remains for us to see how this fermentation started. Nothing is simpler: one has only to mix with the new dough a little of the old dough kept over from the last bread-making and called leaven or rising. This old dough has the peculiarity of making sugar ferment, of decomposing it into carbonic acid gas and alcohol. The noun 'rising' comes from the verb 'rise,' because by virtue of the rising mixed with it the dough rises, swollen by the carbonic acid gas that is generated.
"Rising, as I have just said, is fermented dough left over from the last bread-making. It is lukewarm to the touch on account of the process of decomposition going on within."
"Grape juice gets warm, too, when it ferments," remarked Claire.
"Furthermore," Uncle Paul went on, "rising is much swollen and very elastic on account of the gas imprisoned within its glutinous mass; and it has a pungent, winy odor from the alcohol formed by the decomposition of the sugar it contains. Such, then, is the indispensable ingredient called for, even though in only a small quantity, in order to make fresh dough capable of becoming bread such as we all like so much. To please the palate, salt is also added, but it performs no other office.
"The kneading done, what comes next? I will tell you. Acted upon by the rising that has been evenly mixed with the entire mass of dough, the sugar therein contained decomposes. The carbonic acid gas thus generated remains imprisoned, the gluten merely dilating under its pressure and forming a spongy mass of membranous tissue packed with innumerable tiny closed cavities. Thus the dough rises, swells, and becomes riddled with holes like a sponge. Baking increases this porosity, for the gas, finding itself restrained by elastic glutinous walls, expands still more with the heat and makes the already existing cavities larger. To its highly nutritive quality gluten adds another: by retaining the carbonic acid gas within its multitudinous cavities of all sizes it makes the bread very porous, very light, and consequently easy to digest. Hence it is that a flour poor in gluten, such as rye meal, makes only a compact bread, heavy for weak stomachs; and hence also a flour containing little or no gluten, such as the flour made from rice, from chestnuts, from potatoes, is totally unfit for making bread.
"For perfect fermentation a warm temperature is necessary. That explains why woolen coverings are put over the little baskets of dough to keep in the heat and shut out the cold. If you raise one of these covers and put your hand on the dough you will find it lukewarm and plump. It is warmed by fermentation and swollen by carbonic acid gas."
"Yes, it really is warm," Claire announced, after feeling of one of the unbaked loaves; "and when I press it, it goes in like a rubber ball and then swells out as soon as I take my hand away."
Toward evening the bread came out of the oven all golden-brown on the crust, and filled the house with a sweet smell. The children thought it tasted better than ever, now that they knew how it was made.