Canning at High Altitudes

The following information about canning at high altitudes is provided courtesy of Bernardin Ltd.

In most home canning recipes, recommended processing times for boiling water and pressure canners are stated for use at elevations of 0 (sea level) to 1,000 ft (305 m). Because air is thinner at higher elevations, water boils at temperatures lower than 212°F (100°C) and pressure levels are reached at lower temperatures. Lower temperatures are less effective in destroying microorganisms, so adjustments must be made to assure the safety of home canned foods preserved at higher altitudes.

When using a boiling water canner at altitudes higher than 1,000 ft (305 m), processing times must be extended.

When using a pressure canner at altitudes above 1,000 ft (305 m), the pressure level is increased but the recommended processing time remains constant. The type of pressure canner used determines the pressure adjustment.

Most local elevations or "altitude" can be determined by looking at a local map. Or, refer to the chart below.