Protein & Nutrition Blog – Marmels

Bar chart of bitter compounds in a dried cocoa bean by weight: polyphenols 12 to 18 percent, theobromine 1 to 3 percent and caffeine about 0.2 percent

Protein & Nutrition Blog – Marmels

Why Is Dark Chocolate Bitter? The Compounds Behind It

by Mo Mandegar, PhD on Aug 22 2026
Somewhere between 70 and 85 percent, chocolate stops being a treat for a lot of people and starts being a test. The bitterness is not a flaw in the bar, though. It is a fairly precise readout of the cocoa bean's chemistry: polyphenols at 12 to 18 percent of dry weight, plus theobromine and caffeine. Here is what each compound contributes, and why a more bitter bar is not automatically a more antioxidant-rich one.