HOME CANNING · ALTITUDE
Water boils at a lower temperature as elevation rises. Safe canning compensates by increasing boiling-water processing time or pressure-canner pressure according to the tested recipe.
Find your elevation first
- Use a reliable local government, mapping, or Extension source for the elevation of the kitchen where you are processing.
- Do not rely on a citywide average in hilly or mountainous areas.
- Record the number with your canning notes so every batch begins with the same verified input.
Boiling-water and steam processes
At elevations of 1,000 feet or more, sea-level processing may be inadequate. Increase the processing time exactly as the tested recipe’s elevation table directs. Atmospheric steam canning uses the same time adjustment as the approved boiling-water process and remains subject to its separate 45-minute maximum adjusted process time.
Pressure canning
Altitude adjustments depend on both the tested recipe and whether the canner uses a dial gauge or weighted gauge. Use the table for that gauge type. Do not substitute one gauge’s pressure schedule for the other, and do not change processing time to compensate for incorrect pressure.
Keep the adjustment attached to the recipe
- Mark the correct elevation row before starting.
- Confirm the gauge type and required pressure.
- Start timing only at the required boil or pressure.
- If pressure drops below the required level, return to pressure and restart the full processing time.
- Recheck your elevation after moving or canning in another location.
Sources and further reading
Use a tested process
Use a current tested recipe from NCHFP, USDA, or a university Extension source. Follow its jar size, headspace, preparation method, process, time, pressure, and altitude adjustment exactly.