Before starting, you will need an active ginger bug to kickstart the fermentation. If you don’t have a ginger bug on hand, it takes about 3-5 days to make a new one. (Ginger bug recipe)
Mix the water, yarrow leaves, and brown sugar in a large pot. Bring the solution to a boil and let it boil for 30 minutes. For more flavor and aromatic qualities, add the yarrow flowers during the last 5 minutes of boiling.
Remove the pot from the heat and add the lemons. Allow the solution to cool to room temperature or 70° F (21° C) then strain into a gallon jar.
To speed up the cooling process, you can place the pot in a large bowl filled with ice water. Keep the pot covered to prevent contamination while the solution is cooling.
Add the fresh strawberries, rose petals, and ginger bug. Add more water as needed to fill the gallon jar to the top, leaving about 2 inches of headspace. Mix well to incorporate with a clean spoon and cover the jar with an airlock or tightly woven cloth to keep small bugs out.
Ferment at room temperature for 2 to 3 days. Use a clean spoon to stir the brew several times a day and watch for bubbles to appear when you mix. Taste the brew with a straw and add more sugar as needed to maintain the sweetness level you prefer. Add up to ¼ lb. more sugar.
With a ginger bug, the fermentation is typically very active by day 2. Keep an eye on the strawberries and strain them out before they become mushy and start to smell spoiled.
Strain the soda into a clean container and bottle it, or place it in a clean fermentation vessel with an airlock for a higher alcohol level. See options 1 and 2 for bottling in the notes below.
Notes
Bottling Option 1: For a low-alcohol fizzy soda, bottle the brew immediately into flip-top bottles. Let them sit at room temperature for an additional 8 hours to build pressure. Just remember to burp the bottles to release the pressure every 8 hours or so. Refrigerate the soda once you are happy with the fizziness to slow down the fermentation. Enjoy within a week or so!
Bottling Option 2: For a boozier soda, strain the soda into a glass carboy and top with an airlock. Ferment for an additional 2 or 3 days before bottling. Add a ¼ tsp sugar to each bottle for carbonation. Follow the same steps as above for building carbonation, then refrigerate.
Note: The soda will contain a small amount of alcohol due to the fermentation.
If it’s really warm out, you may want to “burp” your bottles once or twice by opening and then resealing them to release the pressure. This wild fermented soda can really produce a lot of bubbles, so you want to make sure that your bottles don’t explode!