Rinse and pick out any soft berries. Roughly chop them by hand or pulse a few times in a food processor. You're aiming for a coarse relish, not a paste.

Stir in the orange zest. Add honey or maple if you like a sweeter, more traditional flavor.

Place the chopped cranberries in a bowl. Add just enough filtered water to cover. Weigh the mixture and calculate 2% salt. Sprinkle the salt over the mixture and stir well until dissolved. (If using whey or kombucha, add it now.)

Spoon the mixture into your mason jar, pressing gently so the juices rise. Add a splash of filtered water if needed to keep everything submerged.

Place a fermentation weight on top to keep the fruit under the brine. Screw on a loose lid or an airlock.

Let the jar sit at room temperature for 3–5 days (longer if your kitchen is cold). Look for bubbles and a lightly tangy scent.

Once the relish tastes bright and pleasantly tart, tighten the lid and move it to the fridge. It keeps 3–4 weeks.