Chop the beetroot into 1cm chunks and place in a large 1-litre glass bottle or mason jar.
Place the water, salt and kefir starter or any other starter you are using in a jug and stir until fully dissolved.
Pour the prepared water into the bottle over the beetroot chunks and seal the lid. Place the sealed bottle on the kitchen counter for 48 to 72 hours. Once fully fermented place the bottle in the fridge where it will keep for several months.