Use a mandoline to cut the beets into thin rounds.
Place beets, garlic, basil and black peppercorns into a quart-sized wide-mouth mason jar.
Add water and salt (brine) leaving about 2 inches of headroom.
Add whey (optional).
Using a glass weight (pickle pebble) and an airlock, allow to ferment for 3-4 days or until it is bubbling.
Store in the refrigerator for 6-9 months.