What would cause a muffin to have a soapy or bitter taste?

Question

Quizplus · Accepted Answer

Both options A and B can lead to a soapy or bitter taste in muffins. If the chemical leaveners (such as baking soda or baking powder) are not mixed properly into the batter, they can leave behind an unpleasant taste. Similarly, if too much baking soda is used, it can also result in a bitter taste. Using old batter can also affect the taste of the muffins, but it is not specifically related to a soapy or bitter taste.

What Would Cause a Muffin to Have a Soapy or Bitter