In clean, non-metallic bowl, mix the cabbage, juniper berries, caraway seeds, mustard seeds and salt. Stir the cabbage to release the juices. Let rest 10 minutes, then mix again. You may let it rest longer (1-2 hours) if needed.
Sterilize the jar and lid by boiling for several minutes in water and draining on a clean dishcloth.
Pack the cabbage mixture into the sterilized quart jar, pushing down with a wooden mallet or clean hands. Add filtered or non-chlorinated salt water (1 tsp salt per cup of water) to the rim of the jar. Make sure all the cabbage is covered by salt water.
Place jar on a tray to catch any overflowing juices. Keep jar between 65 – 72 degrees F for 2-3 weeks.
After the bubbling stops, check the jar and top off with more salt water (1 tsp per 1 cup of water) if needed. Skim any (harmless) white spots or film from the top, close the jar tightly and store in the refrigerator. It will keep for many months.
