For this recipe, I used a mix of apple cider vinegar and distilled white vinegar. I don’t normally like distilled white vinegar in shrubs, as it can overwhelm delicate berries and stone fruits. But beets are gutsy, and they can handle the stronger flavor.
If you have a favorite recipe for pickled beets, try adding spices from that recipe to this one. For example, if you like bay leaves and mustard seeds in your pickled beets, they’ll work well in this shrub, too. Add them along with—or instead of—the peppercorns and kosher salt.