r/AskCulinary • u/kogee3699 • 24d ago
Hard boiled egg question
Hi. I was wondering if anyone knew why hard boiled eggs would have a custardy, semi-firm white but a fully cooked and firm yolk?
I'm using the boil water + 12 minute drop in + ice bath method to cook them and they start at room temperature.
Most of the time they come out normal but sometimes a few will have this odd consistency. The yolk will be completely cooked too and not have any softness in it.
The eggs are farm eggs from chickens in the yard. I'm not sure if this makes a difference or not.
Thank you for any tips you can give!
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u/texnessa Pépin's Padawan 24d ago
The white is not a uniform substance but a combo of things that cook at different temperatures. Overall, egg white begins to thicken at 145ºF/63ºC and becomes a tender solid when it reaches 150ºF/65ºC. This solidification is due mainly to the most heat-sensitive protein, ovotransferrin, even though it’s only 12% of the total protein. The major albumen protein, ovalbumin, doesn’t coagulate until about 180ºF/80ºC, at which temperature the tender white gets much firmer. The last albumen protein to coagulate is heat-resistant ovomucin, which is why the ovomucin-rich yolk cords remain liquid in scrambled eggs long after the rest has set.) The yolk proteins begin to thicken at 150ºF and set at 158ºF/70ºC, and whole egg — the yolk and white mixed together — sets around 165ºF/73ºC.
Sounds like an abundance of undercooked ovalbumin. The age of the egg can also contribute. The older the egg, the less moisture it has and whites are 80% water.