A Q and A on Safe Home Canning
Safe Home Canning: straight answers to the questions people actually ask, with the figures behind them.
Preserving food in jars at home using tested methods that destroy germs and seal the jar.
Key takeaways
- Low-acid foods: vegetables, meat, poultry and seafood must be processed in a pressure canner
- High-acid foods: most fruits, jams, pickles and properly acidified tomatoes can use a boiling-water canner
- Most useful single change: Use up-to-date tested recipes from the USDA or your local Cooperative Extension office.
- Commonest mistake: Oven canning, open-kettle canning or canning in a slow cooker or multicooker without a tested method.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
What is Safe Home Canning?
Preserving food in jars at home using tested methods that destroy germs and seal the jar.
Why does it matter?
Home-canned vegetables are the most common cause of foodborne botulism outbreaks in the US, and botulism is a rare but potentially fatal illness.
Low-acid foods for Safe Home Canning?
Vegetables, meat, poultry and seafood must be processed in a pressure canner.
High-acid foods for Safe Home Canning?
Most fruits, jams, pickles and properly acidified tomatoes can use a boiling-water canner.
Botulism toxin for Safe Home Canning?
Cannot be seen, smelled or tasted.
What is the single most useful thing to do?
Use up-to-date tested recipes from the USDA or your local Cooperative Extension office.
What is the most common mistake?
Oven canning, open-kettle canning or canning in a slow cooker or multicooker without a tested method.
When should I see a doctor?
Call Poison Control at 1-800-222-1222 or your doctor if you are worried about food from a jar that may not have been canned safely. Call 911 right away for double or blurred vision, drooping eyelids, slurred speech, trouble swallowing or breathing, or muscle weakness after eating home-canned food.
More questions, answered
Can I can vegetables in a boiling-water canner if I process them longer?
No. Boiling water cannot get hot enough to destroy botulism spores in low-acid foods, no matter how long you process. Vegetables, meat, poultry, seafood and soups must be processed in a pressure canner using a tested recipe.
Can I use my electric pressure cooker or multicooker for canning?
Most electric pressure cookers have not been tested for safe home canning, and their temperatures and heat-up and cool-down times may not match what tested recipes require. Use a stovetop pressure canner unless a specific appliance has been tested and approved for canning.
Is it safe to reuse jars and lids?
Canning jars can be reused if they have no cracks or chips. Flat lids are designed for one use, because the sealing compound may not seal reliably a second time. Screw bands can be reused if they are not rusted or bent.
Why do tomatoes need added acid?
Many tomato varieties are close to the line between high- and low-acid foods. Adding bottled lemon juice or citric acid ensures they are acidic enough for safe boiling-water processing. Bottled lemon juice is used because its acidity is consistent, unlike fresh lemons.
If a jar sealed, does that mean it is safe?
Not necessarily. A seal only shows that a vacuum formed. If the food was underprocessed, botulism spores can still survive and grow inside a sealed jar. Safety depends on using a tested recipe and the correct method, time and pressure.
Are freezer jams and refrigerator pickles safe?
Yes, when stored as directed. They are not processed for shelf storage, so they must be kept in the freezer or refrigerator and used within the time the recipe gives.
Related topics
- What the Guidance Really Says About Cooking Methods (Healthy Recipes)
- Food and Water Safety Abroad: Sorting the Evidence From the Noise (Travel Health)
- What the Guidance Really Says About Fruit and Vegetables (Nutrition)
- Foods to Avoid in Pregnancy: What the Evidence Actually Says (Pregnancy and Postpartum)
Where to go next
- Safe Home Canning: Just the Figures
- Safe Home Canning: Sorting the Evidence From the Noise
- Safe Home Canning — the reference entry
- Food Safety: The Complete Guide
- The Evidence on The Four Steps to Food Safety, Without the Hype
- Safe Internal Cooking Temperatures: What Published Guidance Supports
When to speak to a doctor
Call Poison Control at 1-800-222-1222 or your doctor if you are worried about food from a jar that may not have been canned safely. Call 911 right away for double or blurred vision, drooping eyelids, slurred speech, trouble swallowing or breathing, or muscle weakness after eating home-canned food.
Where this comes from
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.
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