Apple cider vinegar is made through a two-step process. First, yeast is added to apple juice to break down the sugars and turn them into alcohol. Then, bacteria is added, which converts the alcohol into acetic acid. The "mother" is the gelatinous and opaque substance that forms in raw, unpasteurized vinegar, and it is often regarded as the most nutritious part of the vinegar. It consists of dozens of strains of good bacteria, which are known as probiotics and are beneficial for the digestive system and the immune system. Many store-bought apple cider vinegars have the mother removed because it gives the vinegar a cloudy appearance, but the mother is actually the healthiest part. When purchasing apple cider vinegar, it's recommended to look for raw, unfiltered vinegar that still contains the mother to get the most health benefits