Common methods for preserving grape jam include "water bath canning," freezing and refrigeration: in order of efficiency and duration. Because grape jam is an acidic food, it can be safely water bath canned, a technique that involves placing the mixture into sterile jars, sealing, and processing with hot water.
As a high-acid food, grapes contain a naturally occurring quantity of pectin that is sufficient enough to ensure proper gelling and resistance to mold. The addition of extra pectin is optional with grape jam, but does assist in its preservation. If the water bath canning method is chosen, depending upon elevation, levels of pectin, and the sterility of the cans being used; processing times will vary by several minutes. Refrigeration can provide up to three weeks of preservation, while freezing may sustain the mixture for a year.