other people's homemade kraut is tart and delicious. why does my first batch smell like farts? i know the fermentation process is smelly, but the end product isn't supposed to be. maybe i should have let it ferment longer -- i couldn't wait more than a week. the only other things in there are kosher salt, nigella seeds and mustard seeds. it tastes good but smells so yucky. why why why why why?