Thoroughly clean and sterilize a one-quart wide-mouth jar and lid. Ensure all surfaces are free of soap residue.

Finely shred the cabbage using a mandoline or sharp knife. Place the shredded cabbage in a large, clean mixing bowl.

Add the sea salt and caraway seeds (if using) to the cabbage. Begin to massage the salt into the cabbage with clean hands. This process should take about 5-10 minutes, until the cabbage softens and releases a significant amount of liquid.

Pack the cabbage and its released liquid tightly into the sterilized jar. Use a tamper or your fist to press down firmly, eliminating air pockets. Ensure the cabbage is fully submerged under its own brine. If not enough brine, you can add a small amount of non-chlorinated water mixed with a pinch of salt.

Place a smaller jar or a fermentation weight on top of the cabbage to keep it submerged. Secure the lid loosely or use an airlock if you have one.

Place the jar at room temperature (around 65-75°F or 18-24°C) for 3-7 days. Check daily to ensure the cabbage remains submerged. You may see bubbles forming, which indicates active fermentation.

Taste the cabbage after 3 days. Once it reaches your desired level of tanginess and crunch, remove the weight and refrigerate. Enjoy as a side dish, topping, or ingredient in other recipes.