Heartburn (pyrosis of the stomach) is an unpleasant, burning pain caused by too much stomach acid. The longer the coffee has been roasted, the less stomach-irritating chlorogenic acid it contains.
Sparkling wine with a lot of carbon dioxide and white wine with increased acidity at a pH value of 2.8 to 3 can stimulate the reflux of increased gastric juice. Heartburn is also commonly equated with the term reflux, which is an oppositely flowing movement of body fluids.