Hard-Boiled Eggs

Hard-boiled eggs keep one week refrigerated, peeled or unpeeled, and they should go back in the fridge within two hours of cooking.

Leave them in the shell if you can. The shell is not the barrier it was — boiling washes away what remained of the protective cuticle — but it still limits moisture loss and keeps the white from picking up refrigerator odors.

Peeled eggs dry out and turn rubbery fast. Store them in a covered container with a damp paper towel over them, or submerged in cold water changed daily.

Do not freeze hard-boiled eggs. The white turns tough, watery, and unpleasantly rubbery. Cooked yolks alone freeze acceptably if you have a use for them.

Easter eggs that sat out for a hunt are a different case: if they were unrefrigerated for more than two hours, discard them rather than eating them.

A hard-boiled egg keeps for one week where a raw egg keeps for five — an enormous reduction, and the reason is that boiling strips away the egg's defenses.

Cooking removes whatever remained of the cuticle sealing the shell's pores, and it denatures lysozyme, an antimicrobial enzyme naturally present in egg white that inhibits bacterial growth. The result is a moist, neutral-pH, high-protein food with no remaining barriers — close to an ideal bacterial medium. Any organism that reaches it after cooking grows without competition.

That is why the two-hour rule matters as much for boiled eggs as for cooked chicken, and why the window is a week rather than a month.

The green-gray ring around a yolk is not spoilage. It is iron sulfide, formed when iron in the yolk reacts with sulfur in the white during prolonged cooking. It is harmless, indicates overcooking, and is avoided by shorter boiling and an immediate ice bath.

Genuine spoilage smells sulfurous and unmistakably rotten — the classic bad-egg smell that no one needs help identifying. A slimy or chalky shell surface is also a discard.