I personally like my kimchi pretty fresh, almost under-ripe. Some prefer a more sour and fully fermented flavor. When the kimchi is to your liking, its ready to place in the fridge.
I've read things on the internet about mold, but I've never encountered any problems with any of my batches, even as I have experimented with various veggies, salt balance, chili blend, etc. If you do encounter mold on the surface of your jars, consult the internet, but it seems to me that the suggested solution is just to scrape off the affected area. Again, I haven't encountered any problems and I don't sterilize my jars or anything special.
The best part of making kimchi is opening the jar for the first time and hearing the suction of the air, followed by the bubbling of the freshly fermenting cabbage. Sometimes it bubbles like a popped bottle of prosecco!
I started making my own kimchi because I adore it and found out that most traditional kimchi isn't vegan. (Sad face.) So, I started making it at home on my own. It is actually very easy on the scale of homemade fermented foods, I've made dozens of batches, its very forgiving and other than one batch coming out a little too salty (my roommate loved that salty batch) I've had nothing but success!
In the very first batch of kimchi I made, I would eat a bite or two here and there; within a few days I realized that my overall mood was elevated, perhaps because of the probiotics.
Kimchi is traditionally made in the spring/early summer and is a great source of natural probiotic, and the ginger/garlic/chili are a natural defense against the bad microbes! Also cabbage is high in vitamin C.
I love kimchi as a relish served with other Asian noodles and stir fry, or even just on its own.
1 Napa Cabbage
1 small daikon radish
2-3 small carrots
4-5 scallions about 1" cube ginger
3-4 cloves garlic
1/3 cup korean red chili flakes (can be acquired at a quality asian grocery or use about half the amount crushed red pepper)
2 tbs sea salt
Rinse the outside of the cabbage (no soap) -- the bacteria that does the magic is on the cabbage, so overwashing could dampen the process.
Coarsely chop the cabbage and scallion, slice the radish and carrot thinly (i use a mandolin). Place in large bowl.
Grind the ginger, garlic, salt, and chili together.
Take the chili mixture and massage it into the veggies. (If you have sensitive skin, use gloves for this part.)
Loosely cover the mixture and let sit for 2-3 hours to start the fermentation. Pack into 2-3 quart mason jars. Push the kimchi down with your fist until there is a layer of liquid that covers the mixture. Leave about 1 inch or more of space between the mixture and the top of the jar as the fermentation will create pressure.
Close the lids loosely, place jars in a dark/cool place for 3-5 days to taste and then place in the refrigerator to slow fermentation.
To read more from Jessica Stickler, read her blog here.