(1696) Cause of sour taste .Now when the clotted Milk , or Curd , had stood for two days in a small glass with a little water that had been poured thereon , its Odour had become so sour as if we had held our noses over sour churned milk .If we now see , as related hereinbefore , that some parts of the clotted milk can remain for more than twenty - four hours in the intestine of a calf , why then should we not think that this may also take place in our stomachs and that such milk or other food that has remained there may become sour , which sourness may brought to our mouths when we bring up wind ? But when we now and then perceive some sourness in the mouth or taste some bile , we will not conclude as soon as we experience some trouble that it is due to too much acid in the stomach , or too much bile .