Rise Up
Natalia Aroca-Ouellette
Point Grey
Floor Location : J 118 P

The purpose of my experiment was to determine if the concentration of yeast affected the density of bread. My hypothesis was that the amount of yeast in the bread will make a difference because the more yeast you have, the more gas is produced during the bread making process therefore the less dense the bread should be. rnTo test my hypothesis, I made many batches of bread. Each recipe, took 5 hours to make and only one variable was altered in each recipe. Every vtach was divided into 2: one half was cooked in a loaf pan and the other on a flat pizza pan. The following parameters were measured for every bread; the crust thickness, the water loss, the volume and the samples were dried to constant mass. From this, the density was calculated. rnThe first dozen batches were all made with different quantities of yeast (2.5g, 5 g, 7g, 10g, 15g and 20g). My results indicated that there is a non linear relationship between the density of the bread and the amount of yeast. This is not consistent with the study of the amount of gas produced as a function of the concentration of yeast. My data suggests that there is a linear dependency of the gas produced on the amount of yeast outside of the bread making process. rnAfter researching the topic further, I hypothesized that the leavening of the bread might also be related to other factors such as amount of sugar and the rising time. When breads were made varying these variables, the least dense bread was made with double the sugar content. Doubling the rising time did reduce the density but not as much as doubling the sugar. rn In order to control the density of the bread, I experimented with different flours. The data, so far, suggests that there is a correlation between the density of bread and the amount of gluten. rnBased on the experiments I made with the crusts, one can conclude that the more yeast you put in the bread, the thicker the crust will be if you cook it on a pizza pan. But the thickness of the crust of the bread cooked in a loaf pan is not affected by the amount of yeast in the recipe.