Why does poaching eggs require gentle simmering not boiling?

Boiling water creates vigorous turbulence that tears apart the delicate egg white before it has a chance to set around the yolk. The aggressive bubbles physically shred the proteins as they try to coagulate, leaving you with ragged, wispy strands floating through the water rather than a cohesive white. Gentle simmering, around 180 to 190 degrees Fahrenheit, provides enough heat to denature and set the egg proteins quickly while keeping the water calm enough to cradle the egg. The soft movement actually helps wrap the white around the yolk. Adding a splash of vinegar also helps by accelerating protein coagulation, giving the white a better chance to hold together before the water motion can disperse it.