Start with a clean surface including hands and all equipment you are using.
Remove the outer leaves of the cabbage. DO NOT WASH THE CABBAGE. The beneficial bacteria is in the cabbage, don't wash it all away. I prefer to use organic cabbage as to avoid pesticide exposure.
Slice the cabbage by first slicing in half, then in quarters. Remove the core and slice the cabbage lengthwise into thin ribbons
Place the cabbage into a large bowl and sprinkle with salt. Using clean hands, massage the salt into the cabbage. Continue to massage and squeeze the cabbage for several minutes. This requires putting a little muscle into it. Gradually the cabbage will become watery and limp. This should take 5-10 minutes.
Your cabbage should begin to look like this once you've properly given it a good rub down.
If you are using caraway seeds or any other spice add it now.
Pack the cabbage into your wide mouth mason jars. Really punch the cabbage down with your fist to attempt to pack the cabbage in and allow the liquid to rise to the surface. Ideally you want the cabbage to be fully immersed in liquid (the liquid that you have produced by rubbing the salt into the leaves). Pour any additional liquid from the bowl into the jars with cabbage. Fill the jars a little more than 3/4 full.
Optional - Use one of the larger reserved outer cabbage leaves over the surface of the sliced cabbage. This will help to keep the cabbage submerged.
Once all of the cabbage has been placed into jars, use either a pickle pebble or another smaller mason jar filled with pebbles or dried beans to weigh down the cabbage and allow the cabbage to remain submerged in liquid.
Cover the mouth of the jar with cheesecloth and a rubberband or twine. This will allow air to pass in and out of the jar while still keeping creepy crawlers out.
For the first 24 hours of fermentation you will need to open the jars and press the cabbage down every so often. I call this step "punch the cabbage". This is to ensure that the cabbage stays submerged and over time the cabbage will become more limp and compact and the liquid will rise to the surface.
If after 24 hours you find that there isn't enough liquid, dissolve 1 tsp salt into 1 cup of water and add more liquid to the cabbage.
Ferment the cabbage for 3-10 days. After 3 days taste the cabbage, I tend to like cabbage at the 7 day mark, but if you like a milder ferment you can stop the fermentation process at 3 days. Keep in mind that you reach peak nutrition around day 7.While the cabbage is fermenting you may see bubbles rise to the surface, this is ok! That is fermentation working. If you see scum rise to the surface you can skim that off and if any mold begins to appear remove it and do not eat that bit.
Once you have reached your desired level of fermentation, remove the cheesecloth, and weights from the jar and close with regular mason jar lid. Store in fridge for 2 months or longer. My rule of thumb is as long as it still tastes good, it's good to eat.
Type of cabbage - you can use napa cabbage, red cabbage, green cabbage, or really any kind of cabbage. They all work!
Temperature - try to keep your sauerkraut at a relatively cool room temperature while its fermenting. I just leave mine on my kitchen shelf away from sunlight or any direct heat source.