Photo by Reese Lloyd.

The following recipe is from the book The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from Around the World. Read more from the author, Sandor Katz, here.

Ginger beer is a classic flavor of homemade soda. It can be made lightly gingered, like most commercial ginger ale, or as spicy as you can take it, using lots of ginger. A ginger bug is a simple ginger beer starter (it can also be used as a starter for other beverages) made from ginger, sugar, and water. Ginger beer can also be made with many different types of starters.

Ginger beer and ginger bug recipe

1. A ginger bug could not be easier to start: Grate a bit of ginger (with skin) into a small jar, add some water and sugar, and stir.

2. Stir frequently, and add a little more grated ginger and sugar each day for a few days, until the mixture is vigorously bubbly. Gingerroots are rich in yeasts and lactic acid bacteria, so ginger bugs usually get bubbly quickly. However, many people have reported that their ginger bugs never get bubbly. My theory is that most of the ginger imported into the United States has undergone irradiation, thus destroying its bacteria and yeast. Foods marketed as organic cannot be irradiated (according to the U.S. Department of Agriculture’s organic standards), so for best results make ginger bug with organic ginger, or ginger from a known, non-irradiated source.

3. Once your bug is vigorously bubbly (or you have one of the other starters), prepare a ginger decoction that will become your ginger beer. I like to make a concentrated decoction that cools to body temperature as it is later diluted with cold water. To make such a concentrate, fill a cooking pot with water measuring about half the volume of ginger beer you wish to make. Add finely sliced or grated ginger, using two to six inches of gingerroot (or more) for each gallon of ginger beer you are making (though only half this volume is in the pot).