Well, well, well. The results are in, and I’m a little surprised.
20 days ago, I started an experiment to see if Vegemite and sugar was enough to start a fermentation.
Why? Several weeks ago we saw many stories in Australia popup that Vegemite was being used to create alcohol.
The BBC (and many other media outlets)…
reported that Indigenous Affairs Minister Nigel Scullion said Vegemite was being bought in bulk to make moonshine, and that because “brewer’s yeast is a key ingredient in the spread”.
I said on Twitter, that hypothesis was that vegemite alone is not enough to cause fermentation, but is instead used (if at all) as a nutrient for the yeast.
It appears that I am wrong.
Vegemite and sugar water alone does appear to ferment, if left for long enough*.
(* please see notes/caveats at the end of the post)
This is a photo taken a few days ago, which appears to show some sort of chemical reaction taking place. I also noticed a week and a half ago, that the glad wrap around the top of the jar was puffed out - likely from the production of carbon dioxide. Both indicate that fermentation took place.
There’s also the fact of the sugar content readings, which I’ll discuss a little more in detail below.
Of the four jar, three underwent fermentation. The control was the only jar not to have any evidence of fermentation take place.
- Control (just sugar water) - no fermentation
- Sugar water + yeast - fermentation
- Sugar water + vegemite + yeast - fermentation
- Sugar water + vegemite - fermentation
In order to show how fermentation took place, I took a final “gravity reading” of each of the jars. The gravity reading shows the relative density of the water. We know that the starting solution was at 1.053.
These are the end readings:
- Control (just sugar water) - 1.053 (0% alcohol by volume estimate)
- Sugar water + yeast - 0.94 (14.8% alcohol by volume estimate)
- Sugar water + vegemite + yeast - 1.000 (6.96% alcohol by volume estimate)
- Sugar water + vegemite - 1.024 (3.81% alcohol by volume estimate)
The control didn’t move at all. This was expected.
What was surprising is that the “sugar water + vegemite” jar, did move. That is, there was a reduction in the gravity - heavily implying some sort of fermentation did take place.
This is also supported by observation. There was evidence of fermentation through fizzy solution, and the bulging of the glad wrap at the top of the jar. Gas, through fermentation, was being produced and was unable to escape.
The second part of my hypothesis also doesn’t stack up. I said the Vegemite, “is instead used (if at all) as a nutrient for the yeast.”
This also appears to be incorrect. If the vegemite was acting as a nutrient, we would have seen a similar result between the vegemite + yeast + sugar water and the yeast + sugar water. Instead the simple sugar water + yeast did best, by quite a wide margin.
So if someone was brewing for alcohol volume, it would appear to be a waste of resources to use vegemite. Simple yeast and sugar water will get a far better result for a much cheaper price. There is no need to add vegemite at all, if yeast is available. However, if yeast is unavailable, using vegemite may be useful to start the process of fermentation. But it’s slow and it’s also possible that wild yeast would be faster.
- The results show that vegemite and sugar water is enough to cause fermentation.
- Vegemite makes a poor nutrient when compared to just yeast and water. It appears better, if going for highest alcohol content, not to add it at all.
This is just one experiment. More experiments should be done to make sure.
There is the possibility that, by chance, the vegemite + sugar water jar was infected by a wild strain of yeast or was contaminated accidentally. It may have only received a very small amount of yeast as contamination, which is why it took so long to get going.
I’m also a little suss with the ABV of the sugar water + yeast. It’s rather high, and I was unaware brewers yeast could get to that level.
TL;DR - This is a guide and a home experiment. It’s just one shitty experiment done by me. Do it yourself to make sure and let me know of the results!