The state of negative pressure in properly heat-processed jars of home-canned foods. When a jar is closed at room temperature, the atmospheric pressure is the same inside and outside the jar. When the jar is heated, the air and food inside expand, forcing air out and decreasing the internal pressure. As the jar cools and the contents shrink, a partial vacuum forms. The sealing compound found on the underside of fresh preserving lids prevents air from re-entering.

1.) Forcing air to escape from a closed jar by applying heat. As a food or liquid is heated, it expands upward and forces air from the jar through pressure buildup in the headspace. 2.) Permitting air to escape from a pressure canner, also called exhausting.

A type of vinegar derived from apples that is light golden in color and has a tart fruit flavor. Cider vinegar has a milder flavor than distilled white vinegar. Because it has color, it may darken white or light-colored fruits and vegetables. In fresh preserving, use 5% acidity (50 grain).

The standard form of vinegar. It is a clear, colorless acidic liquid derived from grain alcohol that possesses a sharp, pungent flavor. Unlike apple cider vinegar or malt vinegar, distilled white vinegar does not compete with the distinctive flavors of herbs and spices in brine. Because it is clear, it does not change the color of white or light-colored fruits and vegetables. In fresh preserving, use 5% acidity (50 grain).

A type of vinegar derived from wine. The flavor reflects the source of the wine.