We started a batch of sauerkraut about a month ago. We used the outer leaves of the cabbage to cover the shredded cabbage below. The cabbage was brined with adequate salt (about 2 tsp per pound). The brine level was well above the surface of the cabbage, which was displaced even more by a plastic bag filled with additional brine.
We last checked it about a week and a half ago, but the brine was at the same approximate level.
Today we checked it, and the brine level was below the surface of the cabbage. The top leaves smelled musty, so I removed them, as well as the 2 or so inches of cabbage below them. At that point, the cabbage smelled exactly as it should - salty, lactic-acidy. It also tastes excellent.
Most recipes I find simply note that if the brine level drops below the surface, just add more brine. My concern is that I don't know how long the brine has been below the surface.
I know most toxins can't survive in a lactic-acid/salt-rich environment, so are we ok? I am planning to hot pack and can today just to be safe, but it seems to be passing all visual/taste/smell tests. My biggest concern would be botulism, but botulism can't survive with that amount of salt.
Am I ok? Or should I err on the side of caution?