Sauerkraut going bad - any ideas?

[Guest guest]

My first couple of batches of sauerkraut were tasty and fine. The last

got a horrible ammonia type smell after just two days of sitting on the

pantry shelf (70 degrees F.) and was much more bubbly. The cabbage rose

above the top of the liquid despite me pushing it down a few times with

a spoon from all the increased effervescence. I made them all the same

way and am conscious of being clean about it. Does this just happen

sometimes? Does anyone use an acidophilus capsule emptied out in it as

a starter perhaps to avoid this?

Experienced krauters feedback welcomed.

Best, M