Making Ginger Beer in the Science Classroom

Fermentation is a type of anaerobic respiration (respiration in the absence of oxygen) carried out by yeasts and other living cells to produce energy for growth and metabolism. In this process, glucose is converted into carbon dioxide, ethanol and energy according to the following equation:

glucose → ethanol + carbon dioxide + energy

When yeast is provided with a source of sugar, water and ginger, it will begin to ferment to produce a bubbly mixture generally incorrectly referred to as a ginger beer "plant" (yeast is a type of fungus). This mixture is supplied with ginger and sugar over several days and is then diluted and bottled. The bottled liquid is then allowed to mature for around one week before it is opened.

The History of Ginger Beer

Ginger beer was first manufactured in Great Britain in the mid 1700s and was introduced to North America by British colonists towards the end of the 18th Century. The original brew had an alcohol content of around 11%, but this was reduced to a much lower percentage during the Prohibition years in America in the 1930s. By 1935 there were around 3000 breweries in Britain, 1000 in Canada and 300 in the U.S.A. The British developed specially glazed stoneware bottles that could effectively transport the ginger beer to countries throughout the British Empire. These included the Ionian islands, Kenya and Tanzania.

Making Ginger Beer – Materials and Teaching Method

Step 1 – Making the Ginger Beer Plant

The following materials and equipment are required per group of around four students:

•                ½ teaspoon dried yeast

•                1 rounded teaspoon ground ginger

•                1 rounded teaspoon sugar

•                1 cup lukewarm water

•                old stocking

•                glass jar

•                rubber band

Students should be instructed to copy down the following directions, which could be followed by a teacher-led explanation.

•                Mix all ingredients together in a jar, cover with a piece of stocking and secure with a rubber band.

•                Each day for the next week, add 1 teaspoon sugar and 1 teaspoon ground ginger.

Step 2 – Making Up the Ginger Beer

To make up the ginger beer, each group requires the following materials:

•                2 cups of sugar

•                2.5 litres of warm water

•                1/4 cup strained lemon juice

•                2 empty 1.25 litre soft drink bottles with lids

•                A clean bucket or other plastic container

Students could also copy down the following directions:

•                Rinse the bottles with boiling water to sterilise them.

•                Add the sugar, water and lemon jiuce to the bucket to make a base syrup.

•                Strain the ginger beer plant through the stocking.

•                Pour the resulting liquid into the syrup and mix well.

•                Bottle and seal. The ginger beer should be consumed within one week.

Making Ginger Beer – Further Investigations

Note that because the ginger beer contains live yeast it has a short shelf life. Students could investigate ways of removing the yeast before bottling as a means of extending the life of the drink. They could also do some research to discover why ginger beer has such a low alcohol content (this is partly because it is only allowed to ferment for a limited period, but also because the added sugar creates an osmotic effect that dehydrates the yeast cells).

References

Madden, Dean. "Ginger Beer- A traditional Fermented Low Alcohol Drink." scienceinschool.org, 2008

Yates, Donald. "Root Beer and Ginger Beer Heritage." The Federation of Historical Bottle Collectors, fohbc.com, 2003.