Ball jars, commonly used for home canning, preserve food by creating a vacuum seal that prevents spoilage.
The Canning Process Explained
Working with Ball canning jars goes just one step beyond cooking. It involves a specific process to make food shelf-stable using heat and the jar's design.
Here's how it works:
- Preparation: Food is placed into clean glass Ball® canning jars, typically with specific lids and rings.
- Processing with Heat: The jars, now filled with food and closed, are subjected to high temperatures. This usually occurs in a water bath canner or a pressure canner, depending on the type of food being preserved.
- Destroying Spoilage Agents: This heat is crucial because it interrupts natural spoilage by destroying food contaminants such as bacteria, molds, and yeasts that could otherwise cause the food to spoil.
- Removing Air: Simultaneously, the heat causes the air inside the canning jars to expand and be expelled. This step removes air from the canning jars, which is essential for creating a strong vacuum.
- Cooling and Sealing: As the jars cool down after processing, the remaining air (now with less internal pressure) contracts. This contraction, combined with the flexible lid design and the pressure difference between the inside and outside of the jar, pulls the lid down tightly against the rim.
- Forming the Vacuum Seal: This cooling process forms a powerful vacuum seal. You can often hear a distinct "pop" sound as the lid seals firmly.
- Preventing Recontamination: The resulting vacuum seal forms to prevent recontamination by keeping any new microorganisms or air from entering the jar, thus preserving the food safely for long-term storage.
In essence, the process uses heat to sterilize the food and the jar's interior, removes the air, and then uses the cooling process to create a vacuum seal that keeps the food safe from further spoilage.
