Fermentation Of Yeast

• databot

• IOS/Android Smart Device

• Warm water (110°F / 43°C)

• Active dry yeast, sugar

• Small bowl and spoon

• Airtight container

Fermentation of Yeast

Fermentation is a biological process carried out by
microorganisms such as yeast and bacteria. During
fermentation, yeast breaks down sugar molecules to
release energy. In this process, carbon dioxide (CO₂)
and alcohol are produced as byproducts.

Yeast is a single-celled organism belonging to the
Fungi kingdom. When yeast is dry or cold, it remains
inactive (dormant). However, when placed in warm
water, it becomes active and begins feeding on
sugar. Warm temperature activates enzymes inside
yeast cells. Enzymes are special proteins that speed
up chemical reactions necessary for life.

Yeast produces energy through a process called
anaerobic respiration. “Anaerobic” means “without
oxygen.” Unlike humans, who primarily use oxygen to
release energy from food (aerobic respiration), yeast
can produce energy without oxygen when it is in a
sealed environment. In anaerobic respiration, yeast
breaks down sugar and releases:

• Carbon dioxide (CO₂)

• Alcohol (ethanol)

• Energy for the yeast cell

The more active the yeast, the more CO₂ it produces
— but is more sugar always better?

Overview

Background

What You Will Need/Prep

• Test your databot™ connection.

• You will be prompted to select
  and connect to databot™ each
  time you launch an experiment.

• If there are two or more
  databot™'s listed, the one
  closest to your device will be
  highlighted.

Have you ever wondered how bread rises or how
tiny organisms create bubbles in dough? Today, you
will learn about a microorganism called yeast and
explore how different amounts of sugar affect its
activity. By feeding yeast various sugar quantities,
you will measure the amount of carbon dioxide
(CO₂) it produces.

• Install Vizeey™ on your
  Smart device.

• Study the background
  information and terms and
  prepare to explore!

Grades: Middle School

Time: 45 Minutes

Subject: Life Science

Topics: Fermentation,
Microorganisms, CO₂ Production, Data
Collection and Analysis

• Scan the QR code to load
  the experiment.

Important Terms

Learning Objectives

In this investigation you will master the following knowledge and skills:

• Visualize, collect and analyze data

• Measure and record CO₂ levels in ppm.

• Understand fermentation as a biological process.

• Identify how sugar concentration affects yeast activity.

• Practice controlled experimental design.

• Use data to determine an optimal biological ratio.

Carbon Dioxide (CO₂): A gas produced during fermentation.

Fermentation: The chemical breakdown of sugar by microorganisms, producing CO₂ and
alcohol.

Microorganism: A microscopic living organism.

Parts per million - (ppm): Usually describes the concentration of something in air, water or
soil. The term ppm expresses the number of units (part) of a given substance that exists as
a portion of a greater substance comprised of one million parts.

Plateau: The point where CO₂ levels stop increasing significantly.

Yeast: A single-celled microorganism belonging to the fungi kingdom.

Too little sugar may limit fermentation because the yeast does not have enough food.
However, too much sugar can slow the process because high sugar concentrations can
draw water out of yeast cells, reducing their activity. This means there is an optimal
balance where fermentation works most efficiently.

At the end of this lesson, you will determine the optimal sugar-to-yeast ratio that results in
the highest CO₂ production. Using databot™, you will observe fermentation in real time and
collect scientific data to support your findings.

In order to work with the experiment you need to launch Vizeey application and click on + in
the upper right corner.

Then select “Add experiment from QR code” and scan the QR code prepared for this
experiment. Your experiment will appear in the list.

You are going to use the CO2 sensor in this exploration.
Let’s test to make sure everything is working properly!

• Bring your databot closer to your mouth and
  breathe on databot, you will see the CO2 levels
  elevate as you exhale CO2.

  • The CO2 is measured in ppm (parts per million).

Now clear your data using and proceed to the
experiment.

When you start the experiment you will be
immediately offered to connect to your databot. Make
sure that databot is enabled.

How to Recognize a Plateau on the Graph

As you observe the CO₂ graph in "The Yeast Beast" Vizeey
experiment, you will see the line begin to rise as yeast
produces carbon dioxide.

A plateau occurs when:

• The graph line stops rising quickly.

• The curve begins to level off.

• The CO₂ values increase very slowly or remain
  nearly constant.

• The graph looks almost flat for several seconds.

When you notice the graph leveling off and staying
nearly flat, that is your signal to stop the experiment
and record the highest CO₂ value displayed.

What do you think will happen when yeast is mixed with warm water and sugar inside a
sealed container? Write your thoughts below.

Predict how CO₂ levels will change as the amount of sugar increases.

• Will CO₂ production increase continuously?

• Is there a maximum point?

• Can yeast be “overfed”?

Write your prediction below.

Part 2: Hypothesis

Part 3: Experiment Procedure

Before starting the experiment, prepare the necessary materials.

You will need:

• • databot;

  • a sealed, airtight container large enough to hold bowl +
    databot;

  • Small bowl for the reaction to take place in;

  • Spoons to measure yeast and sugar

  • Warm water (110°F / 43°C) - ½ cup per trial;

  • Active dry yeast (1 teaspoon per trial);

  • Sugar (½ tsp, 1 tsp, 1.5 tsp, etc.)

  
  

Do you think more sugar will always produce more CO₂?

• Activate the Yeast:

  • Pour ½ cup warm water (110°F / 43°C) into a bowl.

  • Add 1 teaspoon of yeast.

  • Stir gently until fully dissolved.

• Feed the Yeast:

  • Add ½ teaspoon of sugar.

  • Stir until dissolved.

• Set Up the Chamber:

  • Place the open bowl inside the airtight container.

  • Place databot™ inside the same container.

  • Seal the container tightly to prevent ventilation.

• Open the Vizeey app on your smart device.

• Turn on databot (using the small button on the left side)

• Tap on "The Yeast Beast" in Vizeey to load the experiment.

• Start your experiment using: and watch the data!

  • As fermentation occurs, CO₂ levels will begin to rise. Continue observing until the
    graph reaches a plateau — this means the CO₂ level stops increasing significantly
    and begins to level off.

  • As soon as the graph reaches a plateau, stop the experiment using .

• Once you reach a plateau, note the highest CO2 level and time for the tested amount of
  sugar in the table below.

• Repeat the experiment with increased sugar:

  • Clear the previous data set in Vizeey™.

  • Prepare a new yeast mixture using the same amount of water and yeast.

  • Increase the sugar amount (for example: 1 teaspoon, then 1.5 teaspoons).

  • Repeat the experiment following the same procedure.

  • Stop each trial when the graph reaches a plateau and record the maximum CO₂
    value.

Note: Make sure all other variables remain constant (water temperature, yeast amount,
container size) so that sugar amount is the only changing variable.

1/2 cup of warm
water + yeast +
sugar and databot™
inside a container

Seal the container to
avoid ventilation that
may interfere with
your data!

Part 3: Experiment Procedure

Data Collection Tables

Part 4: Data Analysis

Data Collection Table

You will record the maximum CO₂ value at the plateau for each sugar amount tested.

• Create a bar graph to visually compare your results.

  • X-axis: Sugar Amount (tsp)

  • Y-axis: Maximum CO₂ (ppm)

Part 5: Concept Questions

1. Why does yeast need warm water to activate?

1. What gas is produced during fermentation?

Answer the question. Support your conclusion using evidence from your data.

• What is the best sugar-to-yeast ratio for maximum CO₂ production?

• Did you observe signs of “overfeeding” the yeast?

• What pattern do you notice between sugar amount and time to plateau?