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Step-by-Step Guide to Water Bath Canning

Authored by Carol J. Alexander

An easy method of food preservation, water bath canning allows you to put up jars of homemade jam, pickles, and tomato sauce. Whether you garden or take advantage of deals at your local farmers market, water bath canning is a great way to lock in the freshness of summer’s bounty for the year to come.

History of water bath canning

Nicolas Appert, a French confectioner and brewer known as the Father of Food Science, developed the water bath canning method in 1809. The process involves heating a glass jar of food to 212 degrees Fahrenheit and allowing it to cool, which forms a vacuum seal that preserves the contents.

Foods you can process in a water bath canner

Only use the boiling water bath canning method to preserve high-acid foods with a pH of 4.6 or less. You can safely can fruit, tomatoes, pickles, jams, and jellies in a boiling water bath because they contain a high-enough acid content to prevent the growth of Clostridium botulinum spores. Tomatoes, however, are borderline between high and low acids. To be safe, add bottled lemon juice, citric acid, or 5% vinegar to jars of tomatoes when packing. 

What NOT to preserve in a water bath canner

Don't attempt to preserve meat, broth, or low-acid foods like vegetables using the boiling water bath canning method. To kill microorganisms that grow in these foods, you must process them at temperatures greater than 240 degrees Fahrenheit. Unfortunately, no matter how long you boil a water bath canner, it will not achieve temperatures above 212 degrees. To achieve higher temperatures, you need a pressure canner.

Supplies needed for water bath canning

The essentials to water bath canning include a water bath canner, rack, jars, and lids. Specially designed canning jars and lids withstand the high heat of the canning method and come in sizes ranging from a ¼-pint to ½-gallon. Recycled pickle or mayonnaise jars may break in the process. 

In addition, you’ll want a few items to make your canning experience safer and more enjoyable. They include a canning funnel, canning jar lifter, plastic knife or rubber spatula, a kitchen timer, a large spoon or ladle, and a pair of oven gloves. 

For an explanation of how to use each of these items and suggestions for alternatives, see our article Canning Supplies.

How to water bath can: step-by-step

Before processing in a water bath canner, follow these step-by-step instructions on preparing your equipment, gathering and preparing food, and packing the jars. Also, carefully read the recipe you’re using to make sure you understand each step.

  1. Fill your canner or stock pot about halfway with hot water, and turn the burner to medium to keep warm. 
  2. Pack the jars, leaving proper headspace as indicated in the recipe.
  3. Run a plastic knife, chopstick, or narrow rubber spatula around the inside of the jar to release any air trapped in the food.
  4. Wipe the rims of the jars with a clean cloth to remove any food particles.
  5. Apply the flat lid and screw on the band, but not too tightly. To form a vacuum, the air inside the jar needs to escape during processing.
  6. As you pack the jars, place them on the rack in the canner. 
  7. Once the canner is full, add or remove boiling water as needed so that the water rises an inch above the top of the jars.
  8. Place the lid on the canner and turn the burner to high to bring the water to a boil.
  9. Set the timer for the processing time when the water starts a rolling boil. Adjust the burner as needed to keep the water at a steady boil.
  10. When the timer signals the end of the processing time, turn off the stove and remove the lid. Once the water stops boiling, use the jar lifter to remove the jars.
  11. Place the jars, about an inch apart, on a cooling rack or dry towel. Setting a hot jar on a cold countertop could cause the jar to break.
  12. Allow the jars to sit undisturbed for 12 to 24 hours before moving them to long-term storage.

Water bath canning tips for beginners

  • If you have hard water, add a bit of white vinegar to the water bath to prevent calcium deposits on your jars. 
  • If you’re new to canning, ask someone with more experience to join you. Having a knowledgeable guide to demonstrate each step makes the process more fun. 
  • Always follow a tested recipe and use the proper canning method for the food. The National Center for Home Food Preservation is a trusted site for scientifically proven recipes.
  • To avoid disappointment with failed seals, purchase new lids. Jars and bands are reusable, but the flat lids aren’t. 
  • Schedule wisely. Canning is fun but time-consuming. So make sure you have enough time to complete the task before you begin. 

Find everything you need to preserve your harvest. Shop our latest canning equipment catalog so you can stock your kitchen with all the necessary supplies for putting food by to enjoy with friends and family.