Should one prefer olives that are not bitter?

Answer

Not always. The bitter taste of olives comes from phenolic compounds that occur naturally in the fruit, above all oleuropein; an olive can contain more than twenty different phenolic compounds. Freshly picked olives are far too bitter to eat, so processing reduces part of these compounds and makes the fruit edible. Phenolic compounds are part of the natural structure of the olive and are associated with antioxidant properties, which means olives with a slight bitterness may retain more of them. The absence of bitterness therefore does not on its own indicate higher quality; taste and personal preference are decisive when choosing olives.