The Effects of Different Levels of Sugar in the Fermentate upon the Amount of Alcohol Produced After Distillation
by Lester L. Ramdawar Esquire & Jen Rubel
Introduction:
    In class, when we were learning about yeast, we had always used a set mixture for our fermentate. It was always 5 grams of yeast, with 100 grams of sugar, and enopugh water to make 500 mL of fermentate. When we distilled this mixture, we discovered that an amount of alcohol was produced. When time came to choose a lab topic, Jen and I picked one that had always troubled us: How would differences in the level of sugar in the fermentate affect the amount of alcohol produced after distillation? We thought that more sugar in the fermentate would lead to more alcohol, and, in the same vein, less sugar would lead to less alcohol. We felt that sugar was the fuel for the reaction that took place in the fermentate and produced the carbon dioxide. If we added more sugar, more ³fuel² to the mixture, we would have a bigger reaction and would thus lead to more alcohol, we thought. If we have less sugar, we would have less reaction and less alcohol production in the end. Our cohorts, Ari and Jaime, are varying the amount of yeast in the fermentate, to see how that will affect alcohol production.
Methods and Materials:

    First, we had to make a few bottles of fermentate each with different amounts of sugar in it. We chose to test with 50g, 100g, 150g, and 200g of sugar for this lab. We got our bottles and marked off the 500mL mark, which we found by first measuring out 500 mL of water in graduated cylanders and pouring the water into the bottle. Then we massed out 5g of yeast. To mass the yeast and the sugar a special method was used. We put a piece of paper on the scale, and pressed ³TARE² which would zero the scale again. Then we could pour on the yeast or the desired mass of sugar and get our mass, and pour it easily into a bottle. After we massed the yeast, we poured it into the bottle. Then we massed a desired amount of sugar and poured that into the bottle. Then we would fill the bottle up to the 500mL mark with water. We stuck in a rubber stopper with a hose attached to it, into the top of the bottle. The hose ran into a vial of water that we affixed onto the side of the bottle with tape. This vial was so that we could monitor the bubbling, a sign of CO2 production, in the bottle. We repeated this procedure for each bottle that we made. Once the fermentate stopped bubbling, it was ready to be distilled.

    Now we had to set up our distillation apparatus. We got our kits and set them up according to plan. We now had to wait to proceed. We had to wait until the reaction in the bottle was complete. We shook up the bottle and if no more bubbling occurred in the vial, then the reaction was over. If it was over, we would pour about half of the fermentate (250mL) into the flask of the distillation apparatus and turn the heating mantle on. Soon all the alcohol would be separated from the fermentate, and end up in an adjoining flask of the apparatus. This alcohol we then took and massed and figured out the volume of using graduated cylinders. Using the equation D=M/V, we found the density of the clear alcohol and looked on a chart to find the percent alcohol per weight. Next, we multiplied the percentage by two, and found the percent per 500 mL. rather than of the 250 mL that we used as a sample. We repeated this procedure for every trial we conducted. The 100g of sugar trials would be our control, since that was the one everyone used in class.

Results:
    We ran two trials for each sugar measurement, except for the 150g. of sugar. The first two trials of 150 g. were incorrect data, because the fermentat had not finished fermentating before the distillation process began, so the percentages were low.
Raw Data
    # Grams of Sugar Trial # Density % Alcohol 50 1 .967 g/mL 5.28 50 2 .903 g/mL 4.97 100 1 .944 g/mL 9.92 100 2 .954 g/mL 10.30 150* 1 .912 g/mL 9.86 150* 2 .907 g/mL 9.995 150 3 .864 g/mL 15.052 150 4 .860 g/mL 16.872 200 1 .942 g/mL 19.936 200 2 .943 g/mL 19.370 Averages- 50 g. = 5.125 % 100g. = 10.11% 150g. = 15.962% 200g. = 19.653%
Discussion:
    The data showed that the increases in percentage of alcohol were directly proportional to the amount of sugar that was used to make the fermentate. With each 50 grams of sugar that was added to the solution, another 5% of alcohol would be produced. First, when we doubled the amount of sugar from 50 to 100 grams, the percentage doubled from 5 to 10 percent, then, when I raised the amount of sugar again by half, the percentage rose again by half from 10 to 16 percent. The numbers are not exactly proportional, but there is a large margin of error due to the small number of trials that were done, however, the data that was recorded is sufficient to conclude that the amount of sugar in the fermentate does in fact affect, directly, the amount, or percentage, of alcohol in the distillate.

    Another direct proportion that we found was the amount of sugar used in the fermentate to the time of fermentation. The 200g. fermentate took approximately 14 days to ferment, as opposed to the 50 g. fermentate, which only took about 4 days to finish bubbling.

Conclusion:
    Lester and I found that our original hypothesis was correct: The more sugar that is used in fermentation, the larger the percent alcohol would be at the end of the distillation process. What we did not find out, however, is how much sugar can be added before it does not affect the percent alcohol any longer. We believe that there is a limit to the amount of sugar that can be added before the percent of alcohol stablizes at its maximum. The more sugar put into a 500 mL container, the less room there is for water. Therefore there must be a limit. If we had more time, we would continue with the experiment in the pattern that we have started, checking 250 grams of sugar, then 300 and 350.
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