Gently drop an egg in a glass of water. If it lies on its side at the bottom of the glass, then it's fresh. If it stands up, the egg is still good to eat, but might be better for hard boiling. If it floats, then toss it.

Why do my poached eggs sink to the bottom?

If your egg isn't that fresh, you can strain the egg so the thin part of the egg falls out. Add a splash of white vinegar to your water, and while we were split on adding on salt, it seems like salty water leads to an egg that floats in the water, rather than one that sinks to the bottom of the pan.

How do you tell when poached eggs are done?

To check whether they're done, remove one carefully from the pan with a slotted spoon and give it a gentle push with a teaspoon. If it feels too soft (use your instincts), put it back and give the eggs a minute or two more in the water to firm up.