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.
Salt has a deterrent action upon fermentation, even when used in very small quantities. Its action is directly upon the yeast and is not dependent upon other ingredients in the dough.
Salt neutralizes the acidity of the dough, gives flavor to the bread and governs fermentation.
Salt, the same as cold, retards fermentation. Therefore, lightness of the loaf can be influenced by the quantity of the salt used.
From 1% to 2% of salt is used in proportion to the weight of flour made into bread; for milk-bread use 1-3 less salt than for water-breads, and for sweet-breads only one-third of the salt employed for water-bread.
Plenty of salt and a good strong fermentation make a good deal better loaf of bread, as a weak fermentation, assisted by using less salt, not only promotes the likelihood of sour bread, but also makes a loaf without flavor.