The chalaza is a pair of twisted, rope-like strands of egg white that anchor the yolk in the center of the egg. If you’ve ever cracked an egg and noticed white, stringy bits clinging to the yolk, that’s exactly what you were looking at. Far from being a defect or sign of contamination, the chalaza serves a critical structural role, and its prominence is actually a sign of freshness.
How the Chalaza Keeps the Yolk in Place
Each egg has two chalazae, one extending toward the top of the egg and the other toward the bottom. They work like small anchors, attaching the yolk’s outer membrane to the membrane lining the inside of the eggshell. This suspension system holds the yolk in the center of the egg white, preventing it from pressing against the shell wall.
This positioning matters most in fertilized eggs. The developing embryo sits on top of the yolk on a small spot called the germinal disc. By keeping the yolk centered and stable, the chalazae ensure that this disc stays oriented upward, close to the hen’s body heat during incubation. Without this anchoring, the yolk could drift and press against the shell, cutting off warmth and nutrients to the developing embryo. Even in the unfertilized eggs you buy at the grocery store, the chalazae still perform this centering function, which helps protect the yolk’s integrity during handling and transport.
How the Chalaza Forms Inside the Hen
The chalaza doesn’t develop inside the egg after it’s laid. It forms inside the hen’s oviduct, the long tube where an egg is assembled over roughly 24 to 26 hours. As the yolk travels down the oviduct, layers of egg white are deposited around it. During this process, the yolk naturally rotates. That turning motion twists the surrounding egg white into the tight, coiled strands that become the chalazae. This is why they have that distinctive spiral, rope-like appearance rather than looking like ordinary egg white.
What the Chalaza Is Made Of
The chalaza is composed of the same basic protein as the rest of the egg white (albumen), but in a much denser, more structured form. Its primary building block is ovomucin, a glycoprotein that gives egg white its thick, gel-like quality. Research published in Poultry Science found that two specific components of ovomucin are far more concentrated in the chalaza than in regular egg white: one at over four times the concentration, the other at nearly seven times. These proteins are heavily decorated with sugar molecules, which likely contribute to the chalaza’s tough, fibrous texture and help it maintain its structural integrity as a suspension cord.
The chalaza also contains lysozyme, an enzyme with natural antimicrobial properties found throughout egg white. Together, these proteins form a dense, resilient fiber that can hold the yolk in place throughout the egg’s shelf life.
Freshness Indicator
A thick, clearly visible chalaza is one of the easiest ways to tell an egg is fresh. Over time, the proteins in the chalaza break down and the strands become thinner, less noticeable, and eventually almost invisible. So if you crack open an egg and see prominent white cords attached to the yolk, that’s a good sign. An older egg will have faint or nearly absent chalazae, along with a thinner, more watery white that spreads out more in the pan.
Eating and Cooking With the Chalaza
The chalaza is completely safe to eat. It’s nutritious egg white in a slightly different form, and there’s no reason to remove it for most cooking. Scrambled eggs, fried eggs, omelets, baking: the chalaza disappears into the dish without affecting flavor or texture.
The one exception is recipes where a perfectly smooth, silky texture matters. Custards, curds, and some cream-based sauces can end up with tiny lumps if the chalaza isn’t removed. The fix is simple. Either pass your beaten eggs through a fine-mesh strainer before combining them with your other ingredients, or use a fork to fish out the strands from the raw egg. For everything else, you can ignore them entirely.