Prep the cabbage: Remove the outer leaves from the red cabbage and cut it in half. Set one half aside for another recipe (or double this batch!). Slice the other half into quarters, cut out the core, and finely shred using a sharp knife or mandoline. Thin slices help everything ferment more evenly.
Massage with salt: Place the shredded cabbage into a large bowl. Sprinkle with fine sea salt (about 1 tablespoon per pound of cabbage) and massage it with clean hands for a few minutes until it softens. Then, let it rest for 10–15 minutes. You’ll start seeing some liquid pooling at the bottom—this is your natural brine!
OPTIONAL step. Add spices: Toss in any whole spices you’re using like caraway seeds, mustard seeds, or black pepper. Keep bay leaves whole and set them aside to add directly to the jar—this helps prevent too much bitterness.
Pack the jar: Scoop the cabbage into a clean mason jar, packing it down firmly with a tamper or wooden spoon as you go. You want to press out air bubbles and encourage the liquid to rise. Keep packing until the jar is nearly full, but leave 1–2 inches of space at the top.
Top it off: If the cabbage isn’t fully submerged in its own juices, add a bit of 2% brine (1 tablespoon salt dissolved in 4 cups non-chlorinated water). You can wedge in a piece of the cabbage core or use a glass weight to keep the cabbage under the liquid.
Cover: Use a fermentation lid or cover the jar with a clean cloth and secure it with a rubber band. Place the jar on a small plate or dish in case it bubbles over.
Ferment: Let your jar sit at room temperature (out of direct sunlight) for at least 5-7 days. Check it daily to make sure the cabbage stays submerged. You can “burp” the jar by gently opening the lid to release gas if needed.
Taste and store: After a week, give your cabbage a taste. If you like it more tangy, let it go another few days or even 2 weeks total. Once it tastes just right, remove the weight and bay leaves, seal with a regular lid, and transfer the jar to the fridge.