Black coffee is basically alkaline. Star Bucks coffee is alkaline, i.e., it does not cause acid reflex, even when some sugar and nutmeg are added.
Adding sugar and cream or Half and Half dairy cream which is essentially powdered milk makes coffee acidic.
Try drinking coffee black. It is healthier.
The same applies to chocolate. Dark bitter chocolate is good for you. Dark bitter chocolate is alkaline. Milk chocolate is acidic because of the “milk” and the high sugar content.