The Fermentation Challenge!
Name:
By C. Kohn, Waterford WI
Hour
Date Assignment is due: Friday, March 30th
Day of Week
Date:
Why late?
Date
Score:
If your project was late, describe why
Overview: In this week-long lab, you will be hypothesizing, testing, and analyzing to determine unknown information
about the fermentation process. You will be using the Waterford Fermenters to test your hypothesis and collect your
data.
The lab will use the schedule below:
Monday: Introduce topics; hypothesize and discuss rationales.
Tuesday: Initial trial run of fermenters using standard protocol (p. 4); updates to hypotheses
Wednesday: Test hypotheses through experimental trials (designed on p.5, #8)
Thursday: Marketing Research
Friday: Analyze data and confirm or reject hypothesis; if time - class presentations and discussion
Your group will have access to two fermenters. You will decide on Monday what additional materials and feedstocks
you will need in order to run your experiments. All plans must be approved by your instructor prior to beginning. DO
NOT begin your experimental trials until your instructors has read your written plans (p. 5, #8).
Day 1: Review and Discussion
1. In the space below, write all of the things that are necessary for fermentation to occur:
2. In the space to the right, draw or label all components
of fermentation. Be sure to describe all aspects of
fermentation including those things that cannot be
seen (such as a lack of oxygen in the air).
3. What sorts of things would affect the amount of ethanol produced during fermentation? List 3 elements of
fermentation that could be changed and explain the impact of this change on fermentation.
Page | 1
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
4. If the spaces below, describe five things that you do not know about fermentation that you could test during
class this week. (Hint: you could focus on temperature, pH, pretreatment, hydrolysis, type of feedstock, etc.)
5. As a group, choose three topics that could be potential research questions for your work this week. Describe
them in detailed full sentences below:
6. Choose one of your 3 possible items above to work on this week (keep the others in mind in case this particular
item does not work for our classroom setup or is not adequate for experimentation). In the space below, turn
your selected item into a research question.
We wondered if…
7. Turn your research question into a hypothesis by phrasing it as a prediction:
We predict that
Page | 2
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
Experimental Setup
1. Please indicate the option you chose and briefly describe the experiment you intend to perform.
2. What is your independent variable (what you will be purposely changing; only one thing should be changed)?
Our independent variable is
3. What is your dependent variable (what you are measuring)? You can have more than one dependent variable.
Our dependent variable is/are
We will be measuring it in (list the units of measurement that you will be using)
4. Every experiment needs a control, or an untreated replicate, that we can compare to. What will serve as your
control in this particular experiment? Describe as fully as you can.
5. What is your group’s hypothesis? What do you expect to happen?
We predict that
6. What is your rationale? Why do you think your answer to #4 will happen?
We think this will happen because
7. Under what circumstances might the exact opposite of what you expect to happen occur? Describe the
circumstances that could cause your experiment to go in an unexpected direction:
Page | 3
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
Day 2: Fermentation Trial Run - courtesy of
Option 1: Basic Fermentation Recipe using Titration
1. Set up your Waterford Fermenter. DO NOT plug in the heater right away as the glass may crack if the heated
instrument is placed in room temperature water. Check that your fermenter has…
a. A heater
b. A stopper with thermometer and glass tube w/ sampling syringe
c. A plastic vial w/ double-bubble gas trap
d. A magnetic stir bar
e. NO cracks or deformities
f. Clean your fermenter if you see any residues
2. Add to the fermenter: 2 tsp. yeast, and 200 mL warm tap water.
3. Place on stirplate. Cover with lid, including heater. DO NOT plug heater in yet – just let it acclimate to the warm
tap water.
4. Allow mixture to incubate, stirring very fast (700 rpm) with NO heat for 8-10 minutes to activate the yeast.
5. While waiting, remove the plastic vial and add 10 ml of 1 M KOH solution.
a. To make 1 M KOH, dissolve 1.1 g KOH in 100 ml of water in an Erlenmeyer flask or beaker.
b. NOTE: there is a hole in this vial to allow gas exchange! Pour the KOH over the sink and avoid letting it
drip out the hole!
6. Replace the vial into the fermenter.
7. Add 2 tsp. sugar. Reduce stirring speed to medium (350 rpm). Plug in heater, set to lowest heat setting that will
maintain a water temperature of 38-40 degrees C.
a. The heaters are only on or off. If the orange light is on, the unit is heating. When you obtain the
temperature you need, set the heater so that it only turns on if it falls below that setting.
8. After 15 minutes or more, remove the plastic vial and (without dripping out the hole) pour the KOH solution into
a small graduated cylinder.
9. Add 2 ml 1 molar SrCl2.1
10. Add two drops of phenolthphalein. It should turn pink - see your instructor if it does not. Recap your
phenolthphalein bottle.
11. Take your graduated cylinder with your KOH solution to a sink.
12. Turn on the sink’s faucet and let it run at a low setting.
13. Add 37% hydrochloric acid drop by drop to the KOH solution over the sink. Gently swirl between drops.
a. NOTE: HCl acid is EXTREMELY dangerous!!!! Use extreme caution!
b. NEVER add water to acid. Always turn on the faucet and let it run before dumping your acid.
14. Count each drop until the solution turns clear and stays clear. Record the total number of drops below.
15. Wash your fermenter
a. Be careful NOT to lose your stir bar!!!! It will go down the drain if you do not remove it first!!!
b. Use soap and water – do not leave any residues!
c. Wipe your fermenter dry using paper towel and return it to your lab station.
1
1.6 g SrCl2 per 10 ml of water
Page | 4
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
Option 2: Basic Fermentation Recipe using Vernier Probes
1. Set up your Waterford Fermenter. DO NOT plug in the heater right away as the glass may crack if the heated
instrument is placed in room temperature water.
2. Add to the fermenter: 3 tsp. yeast, 300 mL warm tap water, small stir bar.
3. Place on stirplate. Cover with lid, including heater. DO NOT plug heater in yet – just let it acclimate to the warm tap
water.
4. Allow mixture to incubate, stirring very fast (700 rpm) with NO heat for 8-10 minutes to activate the yeast.
5. Add 3 tsp. sugar. Reduce stirring speed to medium (350 rpm). Plug in heater, set to lowest heat setting that will
maintain a water temperature of 38-40 degrees C.
6. After 15 minutes or more, compare the CO2 levels inside the fermenter to those of the room’s air. (Reminder that
CO2 levels are an indirect indicator of the production of ethanol – for every molecule of ethanol produced, one molecule
of CO2 is produced).
7. Repeat this experiment but change one thing (feedstock, temperature, stirring, etc.). Compare your CO2 readings
from the first trial to the second and answer the questions below.
1. Did your fermenter produce ethanol? How do you know?
2. What were your CO2 readings after the first trial run?
3. What did you change in the second trial run of your fermenter?
4. What did you expect to happen?
5. Did this actually happen? Explain:
6. What were your CO2 readings the second time?
7. Is there anything you need to change about your initial experimental plans from yesterday? Explain:
Page | 5
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
8. In as much detail as you can, explain how will you test your hypothesis. Describe your procedure step by step in
the space below. Then make predictions about the impact of your methods.
a. Write your methods like a recipe – include all details necessary to enable anyone to conduct your experiment as intended.
b. What is your expected outcome? Predict how your results will be different from the control and by how
much they will be different (i.e. if you think there will be a weight or height difference, how much of a
difference do you think there will be?)
Page | 6
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
Day 3: Data Collection
Use the spaces below to record all of your data and any relevant observations.
Did your experiment go as planned and as expected? Explain:
If you were to repeat this experiment, is there anything you would do differently to better test your hypothesis?
Explain:
Page | 7
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
Day 4: Data Analysis
1. Restate your hypothesis below:
We hypothesized that…
2. Did your data support your hypothesis?
Explain:
3. How would you explain your results? How was the fermentation process changed in your experiment and how
does this relate to the data you collected? Draft an explanation below and support it with specific data from
your experiment.
4. What have you learned from your work that could increase your production of ethanol in future experiments?
Describe any potential ideas you have at this time based on your work this week:
5. Are there any unanswered questions you still have about this process? List 3 related to your work this week:
Page | 8
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.
Day 5: Wrap-up and Discussion
In the space below, summarize the work, hypotheses, and outcomes of the other 5 experiments performed:
Group
Group
Group
Group
Group
Page | 9
Copyright 2012 by Craig Kohn, Agricultural Sciences, Waterford WI. This source may be freely used and distributed provided the author is cited.