Change in Height of Breads Baked by Different Type of Leavening Agents


  • Geun Jung Lee


Leavening is an inevitable and natural outcome in process of baking breads
regardless of having chemical agents in the dough or not. Leavening causes gas bubbles that
soften and rise the dough. The gas bubbles produced are mostly carbon dioxide or water
vapor. Leavening agents are largely classified into three categories: chemical, biological, and
mechanical. In this research five different leavening agents are tested throughout the baking
process of bread to find out which leavening agents rise the dough more. The five leavening
agents used in this experiment are air, baking soda, instant dry yeast, egg whites, and
sourdough starter. This baking experiment is done over one week with a hypothesis that if
five leavening agents are categorized into different characteristics of leavening process, then
there will also be certain differences in the change of the height of each leavening agent type.
Baking ingredients are limited to 400g of all-purpose flour, 240g water, and 8g salt to prevent
any possible variables that may affect the results. The results are recorded by measuring the
height of the dough center before and after the baking to obtain the change in height. Bread
baking processes are conducted twice per each leavening agent to get a mean value of the
change in height. In order to compare the height change of breads from five leavening agents
and test the hypothesis of statistically significant difference of the height change, one-way
ANOVA analysis is performed by GraphPad Prism 8. The result from a one-way ANOVA
shows a p-value<0.0001 (p<0.05), therefore it indicates that the results have statistically
significant difference in each group. Furthermore, a Tukey Test, post-hoc test, is performed to
find out whether these significant differences from the ANOVA results are mutual among
each group. According to the Tukey Test results, each leavening agent has statistically
significant differences amongst others except for sourdough vs instant yeast. Further research
may be required to test the leavening in more controlled and highly limitation-prevented
environment would show same results from multiple types of leavening agents.