Jar sealing is a method used to preserve food in glass jars by creating a vacuum seal. This process involves filling the jar with food, leaving some space at the top, and then placing a lid on it. When heated, the air inside the jar expands and escapes, creating a vacuum as it cools, which helps to keep the food fresh and safe from bacteria. The sealing process is commonly used in home canning, where fruits, vegetables, and sauces are stored for long-term use. Proper jar sealing ensures that the contents remain edible for months or even years, making it a popular technique among home cooks and food preservation enthusiasts.