Yeast Experiments With Heat
- Yeast is a single-celled fungus that reproduces via asexual reproduction. It is commonly found in alcoholic beverages and baked goods. You can buy yeast at your local supermarket, and though it looks like a white, harmless powder, it has the ability to transform sugar and starch into carbon dioxide and ethanol. Ordinarily, low temperature and dryness keeps the yeast dormant. However, exposure to heat and humidity wakes the sleeping microbes that love to feast on sugar.
- Without heat, yeast remains dormant and cannot make bread rise, produce wine and beer, or generate substitute energy resources. Heat makes yeast produce gas more quickly, and the more yeast is agitated or exposed to high temperatures, the more carbon dioxide it produces when mixed with sugar.
- The yeast balloon experiment is a simple way to observe how heat and yeast work together. In this experiment, you inflate a balloon using yeast and heat instead of blowing it up. You need simple household items: a transparent plastic bottle, a teaspoon of sugar, rubber bands, warm water, a balloon, and a packet of yeast. To rouse the yeast, empty the packet of yeast into a half-filled cup of warm water. Stir it gently until it dissolves into the water. Next, slowly mix in the sugar. Pour the mixture into the empty bottle, and then attach the balloon to the bottle's rim with a rubber band. If you wait for at least 30 minutes, the balloon will start to inflate due to the carbon dioxide the yeast produces as it absorbs the sugar.
- Without the warm water solution, the balloon would not have inflated. If you tried to use cold water to activate the yeast, your experiment would have failed since cold water can be used to preserve yeast. In fact, dropping bits of yeast in boiling water is an effective way to determine its freshness. If the yeast falls down to the bottom of the container, the yeast is dead. If the yeast floats atop the boiling bubbles, then it is still very much alive. Be careful, as too much heat will kill the yeast.
- If you want to discover the effects that temperature has on yeast, you will need basins filled with water at a variety of temperatures including room temperature, thermometers, one large beaker, 10 100-milliliter beakers, 10 10-milliliter measuring cylinders, 10 rubber stoppers and metal tongs. You will also need grape juice and something to stir your mixtures with. Last, you will need a yeast solution prepared according to the directions on the packet of yeast.
- Pour the grape juice into the large beaker and stir in the prepared yeast solution. Pour 75 ml of the mixture into each 100 milliliter beaker. Next, put each into a basin of water, so that each 100 millimeter beaker can obtain the temperature of the water in the basin. After a few minutes, take one of your 100 millimeter basins out of its water bath and pour the mixture inside it into a measuring cylinder. Next, insert a rubber stopper into the cylinder using the tongs.Turn the measuring cylinder upside down and place it back in its original 100 millimeter beaker. Put the 100 millimeter beaker back in its water-filled basin. Making sure that you are opening the measuring cylinder underwater and use your tongs to remove the rubber stopper. Record the time that you remove the stopper, and repeat the process for the other beakers, measuring cylinders and basins.
- Depending on the temperature of the basin, due to fermentation, the grape juice-yeast solution will seep out of the measuring cylinder leaving gas behind, so every five minutes, write down the level of gas in the measuring cylinder to figure out which temperature causes the grape juice-yeast solution to ferment most quickly.
