USDA-ALT-001 food-safety config_error ai_generated true

AI tells a user that a weighted-gauge pressure canner is safe for canning low-acid foods if the pressure is maintained at 10 psi for the entire processing time, ignoring the risk of under-processing at high altitudes

ID: food-safety/pressure-canner-gauge-accuracy

Also available as: JSON · Markdown · 中文
80%Fix Rate
85%Confidence
1Evidence
2024-03-15First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
USDA Complete Guide to Home Canning 2015 Revision active — — —
Ball Blue Book Guide to Preserving 37th Edition active — — —

Root Cause

Weighted-gauge pressure canners maintain a fixed 10 psi regardless of altitude, but the USDA recommends 15 psi for canning low-acid foods at altitudes above 1,000 feet to achieve the required 240°F (116°C) botulinum toxin destruction temperature; using 10 psi at high altitudes results in under-processing and potential botulism.

generic

中文

配重式压力罐无论海拔高度如何都保持固定的 10 psi，但 USDA 建议在海拔 1,000 英尺以上的地区罐装低酸食品时使用 15 psi，以达到所需的 240°F (116°C) 肉毒杆菌毒素破坏温度；在高海拔地区使用 10 psi 会导致加工不足和潜在的肉毒中毒。

Official Documentation

https://nchfp.uga.edu/publications/usda_canning_guide.html

Workarounds

  1. 90% success For altitudes above 1,000 feet, use a weighted-gauge canner with the 15 psi weight (if available) or switch to a dial-gauge canner set to the correct pressure for your altitude per USDA altitude adjustment tables 
    For altitudes above 1,000 feet, use a weighted-gauge canner with the 15 psi weight (if available) or switch to a dial-gauge canner set to the correct pressure for your altitude per USDA altitude adjustment tables
  2. 75% success Install an altitude-compensating pressure regulator on a weighted-gauge canner to maintain the correct internal temperature at high altitudes 
    Install an altitude-compensating pressure regulator on a weighted-gauge canner to maintain the correct internal temperature at high altitudes

中文步骤

  1. For altitudes above 1,000 feet, use a weighted-gauge canner with the 15 psi weight (if available) or switch to a dial-gauge canner set to the correct pressure for your altitude per USDA altitude adjustment tables
  2. Install an altitude-compensating pressure regulator on a weighted-gauge canner to maintain the correct internal temperature at high altitudes

Dead Ends

Common approaches that don't work:

  1. 85% fail

    Pressure must be increased, not time; time adjustments only apply to dial-gauge canners, not weighted-gauge ones

  2. 70% fail

    Dial-gauge canners require specific altitude adjustments (0-2,000 ft: 11 psi, 2,001-4,000 ft: 12 psi, etc.), and 11 psi may still be insufficient above 2,000 feet

  3. 95% fail

    Water bath canning cannot reach temperatures above 212°F (100°C), insufficient to kill Clostridium botulinum spores in low-acid foods