Combine 1 cup filtered water, 2 tablespoons grated ginger, and 2 tablespoons sugar in a quart jar and stir until the sugar is fully dissolved.

Cover the jar with cheesecloth or a breathable cloth and secure it with a rubber band to allow airflow while keeping out debris.

Place the jar in a warm (70°F–85°F), dark spot in your kitchen to encourage fermentation.

Every day for the next 5–7 days, add 2 tablespoons grated fresh ginger and 2 tablespoons sugar to the jar, stirring well to feed the culture.

Watch for bubbles forming on the surface and along the sides of the jar as a sign of active fermentation.

After about 7 days, taste a small amount; it should be tangy and slightly fizzy, indicating readiness.

Strain out the solids using a fine mesh sieve or cheesecloth to obtain the liquid ginger bug culture.

Use the liquid immediately in homemade sodas or store it in the refrigerator; feed weekly to maintain the culture.