Bitter pit means bitterness from chemicals such as caffeine or tannin found naturally within some fruits like grapefruit citrus etc. . It also means bitterness from artificial chemicals like aspartame which are used by many food manufacturers today because they are cheaper than natural sources such as stevia leaves etc. . Bitter pits can cause stomach problems if consumed too much at one time especially if taken with alcohol. It can also cause headaches, dry mouth, nausea, dizziness, vomiting.