Frequently Asked Questions About Home Canning

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Have a question about canning? Find the answer here:

What do I need to get started canning?

Here's a list of everything you need to get started canning.

Which foods can be water-bath canned?

According to current USDA guidelines, all high-acid foods can be water-bath canned. These include:

  • Fruits
  • Pickles
  • Sauerkrauts
  • Jams, jellies, marmalades and fruit butters
  • Tomatoes (with the addition of lemon juice or citric acid)

    Which foods need to be pressure canned?

    All low-acid foods need to be pressure canned. This includes:

    • Vegetables
    • Meats (poultry included)
    • Seafood
    • Beans
    • Stocks and broths
    • Milk

    Which canning methods are considered unsafe?

    Open kettle canning, inversion canning, dishwasher canning, oven canning, solar canning and aspirin/salicylic canning and wax-seal canning have all been deemed unsafe. You can learn more about these canning methods, and why they're no longer considered safe by going here.

    How do you sterilize canning jars?

    1. Place your jars in a canner right side up.

    2. Then, fill the canner with water, stopping an inch above the jars.

    3. Bring the water to a boil and continue boiling for 10 minutes.

    4. Reduce the heat; and keep the jars in the hot water until you're ready to fill them.

    If you live above 1,000 feet in altitude, add one minute of boiling time for each 1,000 foot increase in elevation.

    When do you need to sterilize canning jars?

    Canning jars need to be sterilized before they are filled, if they will be processed in a water bath canner for less than 10 minutes.

    They do not need to be pre-sterilized, if they will be processed in a pressure canner. Sterilization will occur during processing.

    What is headspace?

    Headspace is the unfilled space left between the food in a jar and the jar's lid. This space is purposely left unfilled to provide room for food to expand during processing and to allow a strong vacuum seal to form as the jars cool.

     Since different foods require different amounts of headspace, it's best to follow the instructions set forth in the recipe that you're using.

    How much headspace do I need to leave?

    According to current USDA home canning guidelines you should leave:

    • 1/4 inch for jams and jellies
    • 1/2 inch for fruits or tomatoes that have been processed in a water bath canner
    • 1 to 1­-1/4 inches for low-­acid foods processed in a pressure canner

    What is the cold-pack/raw-pack method?

    The cold­-pack method (also known as the raw­-pack method) refers to a form of canning in which jars are filled with raw (uncooked) foods, and then heat processed.

    What is the hot-pack method?

    The hot­-pack method refers to a form of canning in which jars are filled with hot, cooked foods and then heat processed.

    How do I know if my jars have sealed properly?

    Allow your jars to cool for 12-24 hours, before checking their seal. You'll know they've sealed properly, if:

    • the canning lid dips down in the center
    • pressing down on the center of the lid does not cause it to spring back up
    • when you tap the lid with a spoon it makes a high-pitched ringing sound

    How do you reprocess unsealed jars?

    Follow these simple steps to reprocess any jars that didn't seal properly.

    Is it safe to can vegetables without salt?

    Yes, salt is used in canned vegetable recipes to enhance flavor (not as a preservative), and can be omitted or reduced to suit your tastes.

    One Exception: Do not change the salt content of pickled vegetable recipes.

    Is it safe to can fruit without sugar?

    Yes, adding sugar enhances flavor, and helps fruit to maintain its color, texture and shape, but it's not required for safe canning of fruit. Use the hot-pack method when omitting sugar.

    Is it safe to reduce the salt in pickles?

    The salt content cannot be reduced in fermented or brined pickles. The salt content can be reduced or eliminated in fresh-­pack pickle recipes, but it may affect the texture or taste of the pickles.

    Can you use less vinegar in a pickle recipe?

    No. The acidity of the vinegar is vital to the safety of the food, and should not be reduced.

    This is in accordance with the current USDA guidelines.

    Can you reuse canning lids?

    No. Canning lids have a special sealing compound around the rim that is only good for one use. But that doesn't mean you have to throw them away. They're fine to reuse on jars as long as you won't be canning the contents.

    Can you reuse canning jars?

    Canning jars may be reused, if they have been inspected and found to be in good condition. Discard any jars with cracks or chips along the rim, since these have an increased likelihood of exploding during the canning process, and may not seal properly.

    Also avoid using any jars over 10 years in age – they're fine for food storage, but not for canning.

    Can you double canning recipes?

    It's best to avoid doubling canning recipes because it could affect processing times and alter the consistency of the finished product.

    Is it safe to reuse grocery store jars for canning?

    No. while the jars your store-bought jelly or tomato sauce came in may be stamped "mason" don't be fooled into thinking they're safe to use for canning. They usually aren't as thick as true canning jars and could break or explode when subjected to heat processing. Still another problem: the neck of grocery store jars usually isn't long enough to create a proper seal. They're fine for commercial canning, but not home canning.

    Do home-canned jars need to be stored with the bands on?

    No. The bands (also known as rings) may be removed once the jars have cooled.

    Where can I find someone to teach me how to can?

    Call your local ag extension office to see if they offer canning classes, or check to see if there's a community cannery in your area. If you decide to learn from a friend or family member, make sure they're using current canning practices.

    Have More Questions About Canning?

    The National Center for Home Food Preservation is a great resource. Check out their website for up-to-the-minute information on safe canning practices.

    **The information in this article is based on the current USDA guidelines for safe canning.**