Grow Yeast, Grow
Published on Mar 30, 2017
The objective: Many alcoholic drinks are made through yeast fermentation. Wineries have structures that mix the yeast and juice (like grape) and then send it throgh a series of other chemical reactions to produce the finally result of wine.
The purpose of this project is to find out which juice will cause yeast to ferment the fastest.
My hypothesis is that the yeast in the orange juice will ferment the fastest.
2. Brix Meter/Refractometer
6. Water, Orange, Grapefruit, Lemon, and Cranberry
7. Measuring Cup
8. Masking Tape and Pen
1. Label the bottles, using the tape and pen, Water, Orange, Grapefruit, Lemon, and Cranberry.
2. Pour 100 mL of water into the bottle labeled Water.
3. Repeat step 2 again for the orange, grapefruit, lemonade, and cranberry juice.
4. A pipet was used to collect a small sample of each liquid to place on the Brix meter.
5. The Brix meter was used to measure initial sugar content in each jar for each liquid.
6. The jars were warmed in the microwave for 30 seconds to about 30°Centigrade so yeast could be activated once it was placed in the jars.
7. One teaspoon of yeast was added into all of the jars and stirred for 30 seconds.
8. The jars were left open for one hour, and sugar content was measured every ten minutes with the Brix meter and pipet.
Ideally, the cranberry juice should ferment the fastest and have the greatest sugar loss because of its high sugar content. However, it was observed that the juices that contained some amounts of pulp fermented at a faster rate, like the orange juice which lost a total of about 3 grams of sugar.A thick and gooey substance formed at the both of all liquids. Also, each liquid had bubbles of carbon dioxide forming because the yeast was undergoing cellular respiration, using up the sugar of the juices. At about 30 minutes for each juice, a layer of foam formed on top of each liquid almost instantaneously.
In conclusion, my hypothesis was correct.
The orange juice fermented the fastest, decreasing by 3.08 grams in sugar content.
The Cranberry juice had a loss of 2.45 g of sugar.
The Grapefruit juice lost 1.02 g of sugar.
The Lemonade and water stayed about the same.
Science Fair Project by Veer Sheth