Fuel-Grade Ethanol from Corn Mash

By Kevin Brasser

The unit that I have developed is producing fuel-grade ethanol from corn mash in a laboratory setting to demonstrate how it is accomplished at the industrial level. I feel that I have written a very good lab and it has been very successful for me and exciting to do. The details of the lab are discussed below, followed by descriptions of learning styles used, strategies used, and evaluation techniques:

Fossil fuels are becoming very scarce. Fossil fuels also produce toxic pollutants that contribute to Global Warming and Acid Rain. Ethanol is a fuel that can be produced quite simply from many forms of carbohydrate mash.(i.e. corn, wheat, rice, sugar cane, wood, etc.) Since corn is so very plentiful in the United States at the present time, and probably into the 21st Century, it only seems logical to convert our abundant supplies into fuel-grade ethanol. Furthermore, ethanol burns at high octane and burns clean. In this lab procedure, you will use ordinary corn and simple enzymes to produce real ethanol.

Lab Materials needed:

Corn Mash (20 mesh or finer) 200 g 1000mL+ beaker stoppers
Distilled Water--700mL Autoclave rubber hose
Calcium Carbonate Powder pipettes ring stands
Celsius and Fahrenheit thermometers cooling bath pH paper
*Alpha Amylase cheesecloth pH meter
*Glucoamylase stirring rods HCl
Activated Dry Yeast Fractional Distiller Balance
beaker 50mL Plastic milk jug (gal.) hot plate
ring clamps Safety goggles heat mits

* Diastase of Malt can be substituted, but is not as efficient.

This lab procedure takes approxiamately 2 hours to complete. Please plan ahead according to your teacher's instructions.

  1. Obtain 200 grams of fresh corn mash**--20 mesh or finer.
  2. Add 700 mL of distilled water and stir in 1000mL+ beaker.
  3. Using Calcium Carbonate or HCL adjust pH of "mash" to 5.8.
  4. Add 4mL of Alpha Amylase and stir.(4g of Diastase can be sub.)
  5. Autoclave at 225 F for a minimum of 20 minutes.
  6. Remove from autoclave and cool to 190 F and add 3 more mL of Alpha Amylase, and stir thoroughly. Stir occasionally for 1 hour.
  7. At the end of 1 hour, cool to 90 F and lower pH to 4.2 by adding drops of HCl very slowly. If your mash is in a lump, start over with fresh enzyme.
  8. Add 4mL of Glucoamylase to the mash. Then immediately add 3-4g of yeast that has been activated in warm water.
  9. Transfer the mixture to a stoppered gallon milk jug that has a pipette rubber hose attached to the top. Stopper the jug and place the hose end in a beaker of water to witness CO2 production. Ferment for 48 hours at 88 F or until all visible CO2 production has ceased. Continue to stir occasionally.
  10. Separate the "beer" from the mash by filtering through cheesecloth or a multiple tiered soil sieve into an Ehrlemeyer Flask suitable for distillation.
  11. Distill the "beer" at a temp. that does not exceed 90 C, or water will contaminate your ethanol sample.
  12. Test your ethanol sample with a lit splint--you should see a blue flame. CONGRATULATIONS!!!
  13. You can dry your leftover mash into real distiller's grain--a high fat, high protein hog and cattle feed.

** Materials and some statistics used with the cooperation of ADM Processing, Cedar Rapids, IA 52409

** Corn mash can be obtained in most parts of the United States at local feed mills and stores. It is simply powdered corn, about the consistency of coarse sand. Cracked corn does not work real well because there is not enough surface area for efficient enzyme action. Other materials can be substituted in place of corn mash; things like corn flour, corn meal, rice, other grains, breakfast cereals, bread, pastas, sport drinks, fruit, and anything that is has a good carbohydrate base to it. Be sure that whatever material is used, that it is ground or powdered to a fine mesh of #20 or smaller.

Teaching strategies used included hands-on lab preparations, library research, in-class presentations, laboratory tests, class demonstrations, written updates, research, and conclusion papers, including political ramifications. Students learned that fossil fuels are precious and will not last too much longer; furthermore, they pollute; and that since corn is so inexpensive at this time, that national, even world-wide ethanol production is vital. This lab activity showed that fuel ethanol can be made quite easily and efficiently.

My students were graded on their effort in all the aspects of the project including deadlines for different stages. Grading also included their attitude, work ethic, attendence, accuracy of data, safety procedures used, and their finished paper on the entire project.

The success of this project is because of the hours of "hands-on" activity in the lab, the research involved, the relevance of the real-life application to actually using ethanol as an alternate energy source, and finally, the simple fact that major lab study is fun for most students, and when things are fun, learning takes place.

**E-Mail me if you have any other questions!!! My kids also made ethanol from macaroni, strawberries, cornflakes, soda (pop), maple syrup, etc.! AEKBrasser@aol.com

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