The acetic acid in vinegar counteracts the low stomach acid. Acetic acid makes up 5–6% of apple cider vinegar. So, apple cider vinegar, rich in acetic acid, stimulates production of hydrochloric acid, which helps the digestive process.
It can also help balance pH levels, reducing the occasional burn triggered by the backflow from the stomach into the esophagus. Acid reflux occurs when acid from the stomach flows upward. This causes a sour taste in the mouth and a burning sensation in the chest. And apple cider vinegar is a great way to maintain a proper digestive system.