This section is from the book "A Treatise On Flour, Yeast, Fermentation And Baking Together With RecipesFor Bread And Cakes", by Julius Emil Wihlfahrt. Also available from Amazon: A treatise on flour, yeast, fermentation and baking, together with recipes for bread and cakes.
Large holes in bread are caused through irregular fermentation. All bread will contain some holes, and the difference in this respect constitutes the grain of the bread. A loaf made of a young dough will have a closer grain than one made of a stronger fermentation.
The grain and texture of a loaf, therefore, is partially regulated by the temperature of dough, length of fermentation and amount of salt used.
But there is a limit. As soon as a fermentation passes a certain point, the acid contents of the dough will affect the holes in the bread, sometimes cutting and softening parts of the gluten, and thus cause large holes. This, however, is not the only cause. Bad workmanship, and, as before stated, improper fermentation, often caused through poor yeast, defects in dough-making and moulding of loaves being among them.
The expansion of unevenly distributed gas and particles of undeveloped gluten is mostly the cause. The former is usually caused through poor moulding by inexperienced bakers, or a dough is too tightly moulded after having too much proof.
The undissolved gluten is caused by either a poor ferment, by the use of poor yeast or too high a temperature of dough, which causes too much acidity in the dough. The heat of the oven is also very important.
In sponge bread the large holes are most numerous and often caused through the sponge not being properly broken down and the dough being poorly mixed.
Again, some bakers dust too much flour during the process of moulding, and this often causes the ruin of loaves through large holes.
Again, by the use of moulding machines, which have been in use for a long time, so that the rollers were considerably worn, I have noticed that the loaves would not curl up properly, and have traced the cause of large holes to this source.
Flour that has been in damp storage, or flour that has been exposed too long to a temperature below the freezing point, may also be the cause of large holes in bread.
The salt is another important factor, as improperly dissolved particles can be the cause as well.
There exists many conflicting opinions, simply because it is a rather difficult matter to correct the evil of "large holes."
I would recommend a softer dough; in fact, as soft as it can be handled to advantage; a cool fermentation, 4 ounces of salt to the gallon of liquid and sufficient yeast to bring the dough in time to the bench without prolonging the process of fermentation, and finally more malt extract in place of sugar and a goodly quantity of a well-refined oil.