Fermentation of Yeast & Sugar - The Sci Guys: Science at Home

The Sci Guys conclude the experiment, thanking viewers for watching. They encourage support through Patreon, suggest subscribing for future episodes, invite experiment suggestions in the comments, and ask viewers to like them on Facebook and follow on Twitter. They also invite questions about the episode or science in general.

Ryan and Teresa from The Sci Guys introduce an experiment on fermentation using sugar and yeast. They define fermentation as the chemical breakdown of substances by microorganisms, often producing gases and heat. This episode was a viewer-requested topic.

The materials needed for the experiment include multiple bottles (glass or plastic), sugar, yeast, balloons, a funnel, measuring utensils, and warm water. Although no hazardous materials are used, gloves, goggles, and an apron or lab coat are recommended for protection against spills.

The first step is to add one package (2.25 teaspoons) of yeast to each bottle using a funnel. Then, different amounts of sugar are added: no sugar to the first bottle, 1 teaspoon to the second, 2 teaspoons to the third, and 3 teaspoons to the fourth. Finally, 1 cup of warm water is added to each bottle, which is then gently mixed. A balloon is placed on the spout of each bottle, and they are left in a warm place for an hour or two.

Over the next hour or two, the balloons are expected to gradually grow in size. The bottle with the most sugar will show the largest balloon inflation, demonstrating a direct correlation between sugar content and gas production.

Yeast is a fungus, with approximately 160 known species. It feeds on sugars and starches, breaking them down for energy. During this process, yeast produces carbon dioxide gas and ethanol as waste products. The carbon dioxide gas causes bubbles and inflates the balloons. More sugar means more food for the yeast, leading to greater carbon dioxide production and larger balloon expansion. The chemical equation for this reaction shows sugar (sucrose) as the reactant, yielding ethanol and carbon dioxide.