Booze From a Stone: The Hard Numbers

The experiment described here pertains to a piece on brewing alcohol with Vegemite and science reporting more broadly, which can be found here

The experiment is quite simple in nature and aims, is the yeast in Vegemite still alive and able to proliferate? To establish this, two sets of media will be used to create four test conditions. YPD media inoculated with Vegemite, PD media inoculated with Vegemite (control for yeast extract exposure), YPD media inoculated with dry yeast (positive control), YPD media alone (negative control). Flow chart below:

The inoculated media was incubated for 12 hours at 37c (however I’m sure it’ll work just as well at room temperature away from sunlight). The results are clear both of the media inoculated with Vegemite and the Baker’s Yeast had significant yeast growth after only 12 hours. The negative control media was completely yeast free after this time (figure 1). While I have not tested for the presence of alcohol in the culture I would be extremely surprised if these cells were not fermenting the media.

Under microscopic inspection, the morphology of the Vegemite cultured yeast matched that of the Baker’s yeast. This lends even more evidence to the hypothesis that the yeast in Vegemite is not completely inactivated (Figure 2 and 3). To ensure this is not simply the inactivated remnants of yeast in vegemite I have taken a small sample of YPD Vegemite culture and inoculated more sterile YPD. These results plus the video of my method to follow!