It seems like you experienced a cooking anomaly where the yolk of your boiled egg became hard while the egg white remained runny. This can happen due to a few reasons:
Freshness of the Egg: Fresher eggs tend to have yolks that are more centered and less likely to overcook. If the egg you boiled was very fresh, it could contribute to the uneven cooking.
Temperature and Timing: Boiling eggs requires precise timing and temperature control. If the egg was boiled at too high a temperature or for too long, the yolk can become hard before the egg white is fully set. It's possible that the heat applied during boiling was not evenly distributed, causing this discrepancy.
Size of the Egg: Different-sized eggs can require slightly adjusted cooking times to achieve consistent results. If the eggs used in the batch varied in size, it might explain the difference in the yolk and egg white consistency.
To ensure more consistent results next time, you can try the following tips:
- Start with room temperature eggs, as they tend to cook more evenly.
- Place the eggs in a single layer in a saucepan and add enough water to cover them by about an inch.
- Bring the water to a boil, then reduce the heat to a gentle simmer.
- Cook for around 9-12 minutes for a large egg, adjusting the time slightly for smaller or larger eggs.
- After cooking, transfer the eggs to an ice bath or run them under cold water to stop the cooking process.
These guidelines should help you achieve a more uniform consistency in both the yolk and the egg white.