If tightly sealed, they can explode! What a smell you get after one does that BOOM!

You haven't lived until you make kimchee. :D

Reminds of when my children were small. There job was to do the dishes. One day they decided to stick the soup pot uncleaned in the cabinet. I smelled yuck for weeks and couldn't locate it. When I found the pot, I called my Mommy. I was clueless on how to clean such a pot and live.

I chased down that very smell you are talking about!LOL It took a few days to track it down!(We thought it was milk that my son spilled and didn't tell us about) but, my kraut was in a crock, and it was time to bag it and freeze it! It tastes good, but it isn't as sour as I like!
we love to make it. We have an old crock, I'm sure it may have lead paint, so we lined it with a huge glad bag, called the company to make sure they were food grade, and they are plus they sent me coupons to buy more!!
Lining the crock worked well and I sealed it with a big bowl, and filled bags of water, so it they leaked it would leak in the bowl, and not in the kraut! I had little scum, so I was happy about that!
Brenda

There is mention of culture you can use for making kraut, in another thread.

I also had a strange, elusive smell last summer..... fermenting peppers. ;-)