Begin by thoroughly washing the rhubarb and chopping it into small pieces, about half an inch thick.

In your clean fermentation vessel, mix the chopped rhubarb with sugar, lemon juice, and apple cider vinegar.

Pour in the water to create a balanced mixture and stir gently until the sugar dissolves.

Cover the fermentation vessel with a clean cloth or lid, leaving it slightly ajar. Let sit at room temperature for about 3 days.

After fermentation, strain the mixture using a fine mesh sieve to transfer only the liquid into bottles.

Store the sealed bottles in a cool, dark place for approximately 3 weeks to develop flavors.

After aging, chill the bottles in the refrigerator for a few hours before serving.