Sterilize 1 liter mason jar and utensils in boiling water or by running under very hot water.
Wash and dice beets into 1 cm chunks and place in the mason jar.
Add in salt, whey, lemon and water. Leave a 1 inch gap at the top of the jar.
Leave the jar on the counter top at room temperature for 4-7 days.
Test this beet kvass recipe after 4 days to see if it has fermented enough and has the desired tang. Fermenting longer will result in more tang and fizziness. Store in the fridge when desired taste and fermentation has been reached.