Canning Jar Sterilization Time at Altitude Calculator
Calculate boiling-water and pressure canning sterilization times by altitude.
Get adjusted minutes for safe processing of pickles, jam, tomatoes, and meats.
Canning Sterilization Time at Altitude
Water boils at lower temperatures at higher altitudes, so processing times must be extended to maintain sterilization safety.
Boiling Water Bath (BWB) altitude adjustments (USDA standards). There are two columns, and which one applies depends on how long the sea-level process is:
| Altitude (ft) | Sea-level process 20 min or less | Sea-level process over 20 min |
|---|---|---|
| 0-1,000 ft | No adjustment | No adjustment |
| 1,001-3,000 ft | +5 min | +10 min |
| 3,001-6,000 ft | +10 min | +20 min |
| 6,001-8,000 ft | +15 min | +30 min |
| 8,001-10,000 ft | +20 min | +40 min |
That second column is the one people skip. A 45-minute quart of tomatoes at 5,000 ft needs 65 minutes, not 55. Ten minutes short on a long process is not a rounding error, it is an under-processed jar.
Pressure Canning altitude adjustments (PSI changes, NOT time):
| Altitude (ft) | Weighted Gauge | Dial Gauge |
|---|---|---|
| 0-1,000 | 10 PSI | 11 PSI |
| 1,001-2,000 | 15 PSI | 11 PSI |
| 2,001-4,000 | 15 PSI | 12 PSI |
| 4,001-6,000 | 15 PSI | 13 PSI |
| 6,001-8,000 | 15 PSI | 14 PSI |
| 8,001-10,000 | 15 PSI | 15 PSI |
Common processing times (sea level baseline):
| Food | Method | Pints | Quarts |
|---|---|---|---|
| Whole tomatoes packed in water (acidified) | BWB | 40 min | 45 min |
| Crushed tomatoes (acidified) | BWB | 35 min | 45 min |
| Pickles (cucumber, brine) | BWB | 10-15 min | 15 min |
| Jam / jelly | BWB | 10 min | no tested quart process |
| Salsa (acidified, tested recipe) | BWB | 15 min | no tested quart process |
| Apple butter / fruit butter | BWB | 5 min | 10 min |
| Green beans | Pressure | 20 min | 25 min |
| Carrots | Pressure | 25 min | 30 min |
| Corn (whole kernel) | Pressure | 55 min | 85 min |
| Beef chunks | Pressure | 75 min | 90 min |
| Chicken | Pressure | 75 min | 90 min |
| Chili / soup | Pressure | 60 min | 75 min |
Safety rules, never to be bent:
- Acidic foods (pH below 4.6, fruits, jams, properly pickled vegetables) can use BWB
- Low-acid foods (vegetables, meats, soups) MUST use pressure canning, botulism risk
- Tomatoes need acidification (lemon juice or citric acid) for safe BWB processing
- Always start counting after the water reaches a full rolling boil (BWB) or vent + pressurize properly (pressure canner)
Water bath setup:
- Water must cover jar lids by at least 1 inch
- Process timer starts when water returns to a full rolling boil after jars are added
- Cool slowly (don’t quench): sudden temperature changes crack jars
Pressure canning setup:
- Vent canner for 10 full minutes before pressurizing (purges air)
- Allow pressure to drop to 0 PSI naturally before opening (do NOT release manually)
- Wait 10 min before removing lid
Common altitude regions:
- Denver, CO: ~5,280 ft (BWB +10 min, pressure 13 PSI dial)
- Mexico City: ~7,350 ft (BWB +15 min, pressure 14 PSI dial)
- Cuzco, Peru: ~11,150 ft: exceeds standard tables; consult local extension office
- New Orleans: 1 ft (no adjustment)
- Chicago: 600 ft (no adjustment)
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