What key combination defined Nicolas Appert's revolutionary food preservation technique?

Hermetic sealing combined with heat

Nicolas Appert’s breakthrough method, which paved the way for modern canning, relied fundamentally on two integrated steps. First, the food, placed in glass bottles, had to be sealed securely using a cork and wire or string to create an airtight or hermetic seal. Second, these sealed containers were submerged in boiling water for a precise duration. This heating process was crucial as it drove out the air trapped inside the container and stabilized the contents against spoilage. While older methods like salting or drying focused solely on water removal or hostile environments, Appert's innovation was the combination of sealing out new contaminants while applying heat to neutralize existing agents within the container.