Refining the Efficiency of Alcohol Production During Fermentation.
Isobel Casey
Seycove Secondary Community
Floor Location : S 075 F

Ideally, the fermentation of sugars, by yeast, to produce ethanol (ethyl alcohol), is ultimately limited by the initial supply of sugars and the resulting toxic effect of the ethanol produced by the fermenting yeast cell. The starting liquor, "mash" in brewing or "style" in winemaking, varies widely due to the seasonal and geographical variances in the source sugars (the grapes and grains). Therefore it is essential to be able to quantitatively measure and adjust the biochemistry at this point prior to fermentation. The fermentation process is sensitive to environmental conditions within the starting liquor that includes the starting: pH, temperature, contamination with competitive organisms and the presence of essential minerals and vitamins for yeast cell health. If the fermentation starting liquor biochemistry can be optimally controlled, then the maximum ethanol production may be achieved.

When the process of fermentation stops and the yeast cells either dies or becomes inactive, this is called the "stall point". Any homebrewer or winemaker will attest that one or more of their fermentation vessels have prematurely stalled due to errors in their process. This results in low alcohol content, sweet and poor tasting end product. In industrial alcohol production, this costs millions of dollars. Optimizing fermentation efficiency has a major economic impact within this global industry being in the billions of dollars annually.

I plan to establish reproducible test conditions, that will allow fermentation to occur to its natural stall point for a variety of test conditions. The resulting time to stall point, end alcohol and end sugar concentration, for each test may be observed for comparison. So far, I have conducted a simple two starting liquor test condition pilot trial that produced successful fermentation runs. I have designed and constructed thirteen small 400 ml control vessels for fermentation. I will now conduct a multi-test vessel, simultaneous, test condition trial of thirteen different fermentation environments. Within these test vessels, there will be two pH points, three glucose concentrations, two nitrogen levels and two mineral/vitamin environments to compare. I hope to be able to demonstrate a difference between the test conditions to help define optimal starting liquor biochemical environment for the fermentation conversion from sugar to alcohol.

No exact data of this experiment has been collected yet. However, my hypothesis is that controlling the yeast environment with enough nutrients and within the optimal concentration will increase ethanol yield.