As altitude increases, water boils at a lower temperature. The timings listed are for altitudes up to 1,000 feet. (If you don't know your altitude, call your county extension office.) For higher altitudes, make the following changes:
Boiling-water canning: Use a longer processing time. Call your county extension office for detailed instructions.
Jellies and jams: Add one minute to the processing time for each additional 1,000 feet of altitude.
Pickles and relishes: Processing times vary; call your county extension office for detailed instructions.
Pressure canning: Times remain the same, but different pressures must be used. Call your county extension office for detailed instructions.
Sterilizing jars: Boil one additional minute for each additional 1,000 feet.
Pie fillings: At higher altitudes use these processing times for quarts (in minutes):
Apple: 30 Blueberry: 35 Cherry: 35 Peach: 35
Apple: 35 Blueberry: 40 Cherry: 40 Peach: 40
Over 6000 feet
Apple: 40 Blueberry: 45 Cherry: 45 Peach: 45