Benoît Tavaria

Bitterness can also be a sign of spoilage or rot. Avocados are susceptible to various fungi that can cause internal decay. This might not always be obvious from the outside. The skin might look fine, but inside, the flesh can have brown or black stringy bits or spots that taste very bitter and unpleasant. This is different from the harmless brown oxidation that happens when the cut avocado is exposed to air. Rot-related bitterness is often accompanied by an off-putting smell and a mushy, uneven texture. If your avocado tastes bitter and has any other signs of spoilage, it's best to err on the side of caution and discard it. Don't try to salvage it.