Slice off the beet greens and save them for another purpose (beet greens are loaded with nutrients and can be prepared like chard or kale).
Slice off the bottom of the beet and thoroughly scrub and peel. Coarsely chop the beets and place in a tall glass container.
Add the filtered water, sea salt, and whey and stir to combine. Cover securely and keep at room temperature for 2 days, stirring a few times.
After 2 days, strain out the beets and discard, transfer the liquid to mason jars and store in the refrigerator.
*Don’t use tap water if it is chlorinated because chlorine will inhibit the fermentation process.