Sulfur

Appears in
Professional Cooking: 10th Edition
Professional Cooking

By Wayne Gisslen

Published 2025

  • About
The familiar green ring you often see in hard-cooked eggs is caused by cooking at high temperatures or cooking too long. The same green color appears in scrambled eggs that are overcooked or held too long in the steam table.

This ring results when the sulfur in the egg whites reacts with the iron in the yolk to form iron sulfide, a compound that has a green color and a strong odor and flavor. The best way to avoid green eggs is to use low temperatures and short cooking and holding times.

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