Stressed Out Baker’s Yeast (Saccharomyces cerevisiae): Agitation and Fermentation

Abstract

The process of kneading dough when making bread is a technique used by bakers to increase the oxygen absorption in the dough, causing the bread to rise and expand when baked (Martin et al. 2004). This fact as well as the observation itself prompted curiosity as to the overall impact on yeast fermentation. In order to test this, we set up two falcon tubes with an equal amount of Saccharomyces cerevisiae (Baker’s Yeast), glucose, sodium phosphate, and deionized water. Once falcon tube was then placed on a Vernier stir station and a magnetic stir rod placed in the solution to induce agitation for the whole 60 minutes (experimental group), while the other tube remained undisturbed for the duration of the trial (control group). Two trials were conducted with samples taken from each every 20 minutes to evaluate the increase in cell density over time. Our results concluded that there was a significant correlation between the speed and amount of cell growth and agitation exposure over time. However, this conclusion requires further study into the types of agitation that promote fermentation success and the amount of time yeast can undergo such stress before it no longer becomes beneficial to the product.