Ideally, you want to ferment sauerkraut at room temperature with the right amount of salt for 21 to 28 days. Not only does fermentation preserve food, but it also improves food. Sauerkraut lactic acid fermentation occurs when bacteria break down compounds in sliced cabbage under controlled anaerobic conditions. These lactic acid bacteria produce acids and make minerals, vitamins, and nutrients more bioavailable. Homemade sauerkraut health benefits increase with fermentation time.