This section is from the book "Experimental Cookery From The Chemical And Physical Standpoint", by Belle Lowe. Also available from Amazon: Experimental cookery.
Volume of loaf, cc.
Spring in oven
Color of crumb
Salt. Fritz has reported that the amount of salt used by bakers averages from 1.5 to 2 per cent and varies from 1.35 to 2.12 per cent. The use of salt is important in bread making. If it is not added to the dough, fermentation takes place very rapidly and the bread is too porous. If too much is used, fermentation is slow and the bread is firmer and more compact.
Proportion of ingredients in bread dough. The committee on the standardization of experimental baking tests of the A.A.C.C. have suggested formulas for baking tests, which are given in the laboratory outline, Experiment 73.
Methods of mixing. Straight-dough process. Two processes are used in making bread. One is called the straight-dough process or quick method. In this process all the flour and other ingredients of the bread are mixed together in the dough for the whole fermentation period.
Sponge process. By this method the salt and a part of the flour are omitted during the first part of the fermentation period. Then the remainder of the flour and the salt are added to make a dough, and from this point the manner of mixing and treatment of dough are the same for the two processes. The sponge method is always used with dry yeast and may be used with compressed yeast.
Method of mixing ingredients. The committee on formula and method of mixing, Fitz chairman, have suggested the following procedure. "Thoroughly dissolve sugar and salt in a portion of the water, mix yeast in another. Use water at a temperature to bring dough out at approximately 30°C. Add the solution to the flour, rinsing with balance of water, then add shortening in melted form. Mix thoroughly to a smooth dough. This may require 3 to 10 minutes depending on type of mechanical mixer used. Remove the dough, fold into smooth dough ball and place in battery jar (6 by 8 inches), cover, and place in dough cabinet at 30°C. and let rise until ready to punch." See Experiment 73.
Effect of mechanical treatment on extensibility of dough. Bailey and Le Vesconte have reported that prolonged mixing may destroy the cohesiveness of the gluten.
The most extended experiments on the mechanical modification of gluten quality that have been reported are those of Swanson and Working. They devised a machine with a "pack-squeeze-pull-tear fashion." By mixing the dough for a longer time in this bread mixer they found that the bread could be baked at the end of the first fermentation period, thus decidedly shortening the total time for fermentation. The prolonged mixing altered the gluten quality so that less time was needed for fermentation. "The figures for volume, color and texture show a progressive improvement with the length of time of mixing." Dough mixed for 15 minutes produced a loaf better in every way than a loaf mixed 3 minutes and then fermented in the usual way. When the revolutions per minute were increased from 60 to 120, it was found that 7 minutes would produce as good bread as 15 minutes at the slower rate. The following table gives their results. The first figures are for the control fermented in the usual way after 3 minutes of mixing.