How do you can food step by step?

Canning food is a method of preserving food in which the food contents are processed and sealed in an airtight container. This method allows food to be stored safely for long periods without refrigeration. Here’s a detailed guide on how to can food step by step, including preparation, equipment, and the canning process itself.

1. Understanding Canning Methods

There are two main methods of canning:

  • Water Bath Canning: Suitable for high-acid foods such as fruits, jams, jellies, pickles, and tomatoes with added acid (lemon juice or vinegar).
  • Pressure Canning: Required for low-acid foods such as vegetables, meats, poultry, seafood, and soups.

2. Gather Necessary Equipment

Basic Equipment:

  • Canning Jars: Glass jars specifically designed for canning, with two-piece lids (flat lid and screw band).
  • Water Bath Canner: A large pot with a rack and a lid for water bath canning.
  • Pressure Canner: A heavy-duty pot with a locking lid, a rack, and a pressure gauge for pressure canning.
  • Jar Lifter: To safely remove hot jars from the canner.
  • Lid Lifter: A magnetic tool to lift lids out of hot water.
  • Funnel: To fill jars without spilling.
  • Bubble Remover/Headspace Tool: To remove air bubbles and measure headspace.
  • Clean Towels: To wipe jar rims and for handling jars.

3. Prepare the Food

Selecting Ingredients: Choose fresh, high-quality produce. Wash and peel (if necessary) the fruits or vegetables.

Pre-Cooking: Some recipes require pre-cooking the food before canning. For example, tomatoes are often simmered before being canned.

4. Sterilize the Jars and Lids


  1. Wash: Clean the jars, lids, and bands in hot, soapy water. Rinse thoroughly.
  2. Sterilize: Place jars in a large pot of boiling water for 10 minutes to sterilize them. Keep them hot until ready to use. Lids should be heated in simmering water but not boiled to maintain the integrity of the sealing compound.

5. Fill the Jars

Packing the Food:

  1. Hot Pack: Food is pre-cooked before packing into jars. This method often helps remove air from the food.
  2. Raw Pack: Raw food is packed into jars, and hot liquid is poured over it.

Filling the Jars:

  1. Add Food: Use a funnel to pack the jars with food, leaving appropriate headspace (the space between the food and the rim of the jar) as specified in the recipe.
  2. Remove Air Bubbles: Slide a non-metallic spatula or bubble remover tool around the inside of the jar to release trapped air bubbles.
  3. Wipe Rims: Wipe the rims of the jars with a clean, damp cloth to remove any food residue.
  4. Apply Lids: Place the flat lids on the jars and screw the bands on fingertip-tight.

6. Process the Jars

Water Bath Canning:

  1. Prepare the Canner: Fill the water bath canner half-full with water and preheat to 140°F for raw-packed foods or 180°F for hot-packed foods.
  2. Load the Jars: Use a jar lifter to place the filled jars onto the canner rack. Ensure the jars are covered by 1-2 inches of water.
  3. Boil: Bring the water to a rolling boil. Start the processing time once the water reaches a full boil. Process for the time specified in your recipe.
  4. Cool the Jars: Once processing is complete, turn off the heat and let the jars sit in the canner for 5 minutes. Use a jar lifter to remove the jars and place them on a towel or rack to cool undisturbed for 12-24 hours.

Pressure Canning:

  1. Prepare the Canner: Add 2-3 inches of water to the pressure canner.
  2. Load the Jars: Place the filled jars on the rack inside the canner.
  3. Seal the Canner: Lock the lid in place. Allow steam to vent for 10 minutes to ensure even temperature distribution.
  4. Process: Apply the weight or close the vent according to the canner’s instructions. Bring the canner to the required pressure (as specified in your recipe) and start the processing time.
  5. Cool the Canner: Once processing is complete, turn off the heat and allow the canner to cool naturally to 0 pressure. Do not force-cool the canner. Once pressure is normalized, carefully remove the lid.
  6. Cool the Jars: Use a jar lifter to remove the jars and place them on a towel or rack to cool undisturbed for 12-24 hours.

7. Check the Seals and Store

Check Seals:

  1. After Cooling: After 12-24 hours, check the lids for a proper seal. The lids should not flex up and down when pressed.
  2. Reprocess or Refrigerate: If a jar hasn’t sealed properly, you can either reprocess it with a new lid within 24 hours or refrigerate and use it within a few days.

Label and Store:

  1. Label: Write the contents and date on the lid or jar.
  2. Store: Store the jars in a cool, dark, and dry place. Properly canned food can last up to a year or more.

Sample Recipe: Canned Tomato Sauce


  • 20 pounds of tomatoes
  • 1 cup chopped onions
  • 5 cloves garlic, minced
  • 1/4 cup olive oil
  • 1/4 cup lemon juice (for acidifying)
  • Salt to taste


  1. Prepare Tomatoes: Blanch, peel, core, and chop the tomatoes.
  2. Cook Sauce: In a large pot, sauté onions and garlic in olive oil until tender. Add tomatoes and simmer until the sauce thickens (about 1-2 hours). Season with salt.
  3. Sterilize Jars: Sterilize jars and lids as described above.
  4. Fill Jars: Add 1 tablespoon of lemon juice to each pint jar (2 tablespoons per quart). Ladle the hot sauce into jars, leaving 1/2 inch headspace. Remove air bubbles, wipe rims, and apply lids.
  5. Process Jars: Process in a boiling water bath canner for 35 minutes (adjust time for altitude).
  6. Cool and Store: Cool jars undisturbed for 12-24 hours. Check seals, label, and store.


Canning food is a time-honored method of preserving seasonal produce and enjoying it year-round. By understanding the different canning methods, preparing the necessary equipment, and following the proper steps, you can safely and effectively can a variety of foods. Consistency and attention to detail in each step—from selecting ingredients to processing jars—ensure the safety and quality of your canned goods. Happy canning!

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