Preserve food safely
Choose drying, freezing, fermentation or canning by food type—and know when not to improvise.
Critical caution: Low-acid canning errors can cause botulism without obvious smell or taste. Use only current tested recipes and correct equipment.
- Time
- Method dependent
- Difficulty
- High
- Outcome
- Extend food life without introducing botulism or other contamination
Survival lens: Back-to-basics preservation is valuable, but historical practice must be filtered through modern microbiology. Tradition informs what to preserve; tested processes determine how.
Before you begin
- Reject spoiled or flood-exposed food
- Confirm the recipe and equipment match the food
- Clean hands, surfaces and vessels
What you need
- Current tested recipe
- Food thermometer
- Accurate scales and measures
- Correct jars, lids or drying equipment
- Labels
Step-by-step procedure
- Match method to food. Drying, freezing, fermentation, water-bath canning and pressure canning are not interchangeable. Low-acid foods require an approved pressure process.
- Use an exact tested recipe. Do not change jar size, ingredient proportions, acidity, processing time or pressure unless the authority explicitly permits it.
- Prepare equipment. Inspect jars and lids, calibrate thermometers or pressure gauges as required, and keep the work area organised.
- Control the critical variable. Maintain the specified temperature, acidity, salt concentration, pressure and time. Adjust for altitude where the tested process directs.
- Cool and inspect. Follow the specified cooling method. Check seals without disturbing them prematurely. Label every batch.
- Store and discard safely. Keep cool, dark and dry. Discard leaking, bulging, spurting, unsealed or otherwise suspect containers without tasting.
How to check it is working
- Recipe is from a recognised current authority
- Correct canner and jar size were used
- Critical processing values were recorded
- Every container is labelled and inspected
Common mistakes
- Open-kettle, oven, microwave or dishwasher canning
- Adding extra starch or low-acid ingredients
- Using antique closures for canning
- Tasting to assess botulism risk
Sources and further reading
- USDA / NCHFP: Complete Guide to Home Canning (PDF)
- NCHFP: Equipment and methods not recommended
- NCHFP: Recommended canners
How this guide was checked
Official-source aligned: Aligned with USDA / NCHFP tested-process guidance
Independent specialist review: not yet completed. How review works.
Last updated: Nov 2026 · edition 1.0.
Open in the library to print or download · Suggest a correction · Kit planner