Why is stewed eel bitter?

Eel stew is bitter. Maybe the fish gall is broken or the seasoning is wrong.

The correct way to stew eel;

Ingredients: eel, celery, ginger, onion, salt, monosodium glutamate, pepper, yellow wine and corn flour.

Practice steps:

One: the eel is boned and cut into strips, and pickled with onion, ginger, yellow wine, a little salt and monosodium glutamate.

Two: pat the salted fish with raw flour.

Three: put the base oil in the pot, put the onion and ginger in the wok, stir-fry the eel bones a little, add a little yellow wine and cook for two or three minutes.

Four: eat eel meat and run away. Add celery. Turn off the heat until the soup turns white, and then turn off the heat after seasoning.

Five: Sprinkle some pepper before serving.