Wash your glass jar thoroughly with hot soapy water and rinse well to remove any soap residue. Chop or grate 2 tablespoons of fresh ginger with the skin on, keeping the pieces small to maximize surface area for the wild yeasts.

Add the chopped ginger and 2 tablespoons of sugar to your clean jar, then pour in 2 cups of filtered water. Stir vigorously with a non-metal spoon until the sugar completely dissolves into the water.

Cover the jar with a breathable cloth, coffee filter, or paper towel secured with a rubber band. Place the jar in a warm spot in your kitchen, ideally between 68 to 78 degrees Fahrenheit, away from direct sunlight.

Starting on day two, add 1 tablespoon each of freshly chopped ginger and sugar to the jar. Stir well with your non-metal spoon, then re-cover and return to its warm spot.

Continue the daily feeding for five to seven days total, watching for signs of active fermentation. You should start seeing small bubbles forming around the ginger pieces by day three or four, with more vigorous bubbling by day five.

Your ginger bug is ready when it bubbles actively within a few minutes of stirring and has a noticeably fizzy, tangy smell. Pour a small amount into a glass and listen for a slight fizzing sound, similar to opening a soft drink.

Once active, strain out the amount you need for your recipe through a fine mesh strainer. Use about 1/4 to 1/2 cup of strained liquid per quart of soda or beverage you're fermenting. The strained ginger pieces go back into your jar to maintain the culture.

After using some bug for a recipe, continue feeding the remaining culture every one to three days if kept at room temperature. When you feed it, add equal parts ginger and sugar, usually 1 tablespoon of each. If your bug gets too full of ginger pieces, strain out and discard about half before feeding.