Adjustments for High-Altitude Canning
Home cooks who live at high altitudes may be used to adjusting recipes; high-altitude adjustments apply to home canning, as well. Canning food safely requires your filled jars to be processed at a specified temperature or pressure level for a specified amount of time. If you live at altitudes higher than 1,000 or 2,000 feet above sea level, adjust your canning recipes for food safety.
Water-bath canning: Generally, recipes are written for water bath canning at altitudes less than 1000 feet. If you live higher than 1,000 feet above sea level, follow these guidelines:
For processing times of less than 20 minutes: Add 1 additional minute for each additional 1000 feet of altitude.
For processing times of more than 20 minutes: Add 2 additional minutes for each 1000 feet of altitude.
Pressure Canning: Pressure canning recipes are generally written for altitudes of less than 2000 feet. If you live higher than 2000 feet above sea level, make this adjustment: Increase pounds of pressure by 1/2 pound for each additional 1,000 feet.