Fermentation has been used by mankind for thousands of years for raising bread, fermenting wine and brewing beer. The products of the fermentation of sugar by baker’s yeast Saccharomyces cerevisiae (a fungus) are ethyl alcohol and carbon dioxide. (Here is a page on the chemical reactions involved in glycolysis and fermentation.) Carbon dioxide causes bread to rise and gives effervescent drinks their bubbles. This action of yeast on sugar is used to ‘carbonate’ beverages, as in the addition of bubbles to champagne).
We will set up a fermentation in a closed system and capture the generated carbon dioxide to carbonate our home made ginger ale. You may of course adjust the quantities of sugar and/or extract to taste. Note that the lemon called for in step eight is optional. And if you want a spicier drink, you can increase the amount of grated ginger. As with any yeast fermentation, there is a small amount of alcohol generated in the beverage (about 0.4%).
- Clean 2 liter plastic soft drink bottle with cap (not glass: explosions are dangerous.)
- Grater (preferably with fine “cutting” teeth
- 1 cup measuring cup
- 1/4 tsp and 1 Tbl measuring spoons
- Cane (table) sugar [sucrose] (1 cup)
- Freshly grated ginger root (1 1/2-2 tablespoons)
- Juice of one lemon
- Fresh granular baker’s yeast (1/4 teaspoon)
- Cold fresh pure water
Once the bottle feels hard to a forceful squeeze, usually only 24-48 hours, place in the refrigerator. Before opening, refrigerate at least overnight to thoroughly chill. Crack the lid of the thoroughly chilled ginger ale just a little to release the pressure slowly. You do not want a ginger ale fountain!
Do not leave the finished ginger ale in a warm place any longer than the time it takes for the bottle to feel hard. Leaving it at room temperature longer than two days, especially in the summer when the temperature is high, can generate enough pressure to explode the bottle! (Speaking from experience here…) Once it is thoroughly chilled, there is little danger of explosion.
Filter the ginger ale through a strainer if you find floating pieces of ginger objectionable. These are found in the first glass or two poured, and, since most of the ginger sinks to the bottom, the last glass or so may require filtering too. Rinse the bottle out immediately after serving the last of the batch.
There will be a sediment of grated ginger and yeast at the bottom of the bottle, so that the last bit of ginger ale will be carry ginger fibers. Decant carefully if you wish to avoid this sediment.
The gas will develop faster in ginger ale than in home made root beer, presumably because there are more nutrients in it than in root beer extract.