Safe canning starts with research, tested recipes

As gardens begin producing strawberries, beans and other crops in the months ahead, many home gardeners start thinking about ways to preserve their harvest.

Canning is one of the most common methods, but food safety experts say it’s important to follow tested instructions rather than relying on memory or older techniques.

“Memorization is going to get you in trouble,” said Susan Hill, a regional food safety and quality extension agent with the Alabama Cooperative Extension System who works with residents across northwest Alabama, including Franklin County.

Hill said research over time has improved understanding of bacteria and food safety, leading to updated recommendations for home food preservation.

Because of that, she encourages home canners to consult reliable sources each time they prepare food for storage.

“Always read the instructions and always go to a reliable website and look,” Hill said. “Following the instructions is what’s going to get you safe food.”

Hill recommends the National Center for Home Food Preservation as a trusted source of research-based information.

The website — nchfp. uga.edu — provides tested instructions for canning, freezing and drying many types of food.

Understanding when to use a water bath canner versus a pressure canner is one of the most important concepts for beginners.

“If it is a jelly or a jam or a marmalade or you want to make a pickle, you can use a water bath canner,” Hill said. Fruit spreads and pickled foods are naturally acidic, which helps prevent the growth of harmful bacteria during processing.

Vegetables and other low-acid foods require a different approach.

“If you’re wanting to can green beans or vegetable soup or beans, you have to use a pressure canner,” Hill said.

Hill said botulism spores naturally occur in soil and can grow in lowacid foods sealed in jars without oxygen.

Botulism is a rare but serious illness caused by toxins produced by the bacterium Clostridium botulinum.

Pressure canners reach higher temperatures than boiling water and are necessary to destroy the bacteria in low-acid foods.

Improperly processed food can pose serious health risks.

“It can kill you,” Hill said.

She said the acidity of the food determines which canning method is safe.

Because of that difference, acidic foods like jams and jellies can safely be processed in boiling water, while vegetables require the higher heat of a pressure canner.

Proper jar preparation is another important step in safe canning.

Hill said canners should inspect jars for cracks or defects, wash them in hot soapy water and keep them warm until they are ready to be filled with hot food.

Keeping jars warm helps prevent breakage when hot food is added.

Hill also noted that modern canning lids no longer need to be boiled before use.

She said practices such as turning jars upside down to seal them were once common but are no longer considered safe.

For gardeners, preserving produce can be a practical way to store extra harvest.

Fruits such as strawberries and blueberries can be used to make jams or jellies, while vegetables like green beans can be safely preserved using pressure canning.

Hill said pressure canners that use dial gauges should also be checked regularly to ensure they are working correctly. Extension offices can often test gauges for accuracy.

Ultimately, she said safe canning comes down to following tested instructions every time. “Always read the instructions,” she said. “Never trust your memory.”