Canning fruits and vegetables runs in my veins, though it took me many years to admit it. My paternal grandmother had an area in the basement where she kept all of her home-canned goods, including pickles, green beans, apple butter, tomatoes, tomato juice, jams, and jellies. My mother canned vegetables, jams, and jellies practically every year when I was growing up. Dad brought home bushels of string beans, spread out an old sheet and dumped the beans on top, and then we’d spend a morning or afternoon stringing and snapping the beans for mom to can. I didn’t think it was very fun and I swore to myself that I would never do any canning when I grew up.
Well, many jars of jams, jellies, and salsas later, I have to say that’s one promise I couldn’t keep; the lure of making my own was just too strong. Five years ago I bought the Ball Blue Book (the older version) and some equipment at my local discount store and off I went. My sister had also said that she would never do any canning, although she caved sooner than I did. She has all the gear for acid and low-acid canning, and even had a stove in the basement of her last house that she used strictly for canning. Canning is hot work and the cool basement made it more bearable.
You don’t need a huge space for canning, although having at least a little counter space helps. The last house we lived in was a small, craftsman bungalow with a kitchen that Michael referred to as the “space shuttle kitchen.” It was the smallest kitchen I had ever worked in, even smaller than the tiny kitchens I had overseas. And despite having a counter space that was only 18 inches by 24 inches, I was able to do some summer and fall canning.
Consider this post a canning primer, a very brief summary of the basics of boiling water canning. I highly recommend checking out some of the authoritative sites and books in the Resource list below and purchasing some basic canning supplies to help you safely enjoy your canning experience.
For health reasons you should NOT rely solely on this summary. (LEGAL DISCLAIMER: Remember, I am not a cooking professional.)
[Updated May 2020.]
Acid foods can be processed in a boiling-water canner. Acid foods include fruits and tomatoes, though tomatoes will require a little extra acid from citric acid, vinegar, or lemon juice. Always use a recipe specifically designed for canning. If the recipe does not state that it is designed for canning, then beware. If the recipe does not have enough acid, you could run into nasty contamination problems.
Low-acid foods should always be processed in a steam-pressure canner. They should NEVER be processed using the boiling water method. This method does not reach the super-high temperatures necessary to kill certain bacteria and their toxins which produce botulism. Low-acid foods include vegetables, meats, poultry, and seafood. I have never attempted low-acid canning and probably never will. (Ok, obviously I shouldn’t say never…) [Update: Actually, I started steam-pressure canning in 2012 because we had such a huge tomato harvest.]
- boiling-water canner and lid
- rack (should come with the canner)
- large 8 to 12 quart pot (for heating the lids and sterilizing the jars)
- cooking thermometer (absolutely required, do not try to guess the temperature)
- jar lifter
- jar funnel
- plastic spatula
- lid wand
- new lids and bands (ALWAYS use new lids. They are not reusable. Bands can be reused if they are not warped or rusted. If you aren’t sure, spend a couple bucks and buy some new bands just to be safe.)
Some of these sound silly (lid wand?), but I found it very helpful. It’s basically a long handle with a magnet embedded in one end that allows you to easily remove the metal lids and bands from the hot water. You can find a canning tool kit for around ten dollars or so that includes the lifter, funnel, spatula, and lid wand. I found mine in a discount department store. You may also find complete kits that contain the canner, rack, and all the smaller pieces. Jars are always sold separately.
Equipment to Avoid
- old-style or antique jars
- commercial jars, like the ones in which you buy commercially prepared mayonnaise
- zinc caps and glass lids with jar rubbers
- one-piece commercial caps
Check your equipment carefully to make sure that the jars are not chipped or cracked, and that the lids and bands are not warped.
Always start with clean equipment so that you don’t introduce unpleasant microorganisms into your preserves. Wash your jars, bands, and lids in hot, soapy water. Rinse thoroughly in hot water. You may also run them through the dishwasher.
For hot pack foods, jars must be heated prior to packing to prevent breakage due to temperature shock. Submerge the jars in just enough water to cover and bring to a boil. Turn the heat off and leave the jars in for at least 10 minutes.
If you are making jelly or any other product that is processed for less than 10 minutes, you must sterilize the jars instead of just heating. Place the jars in a large sauce pot and cover with water. The jars must be totally submerged. Bring the water to a boil and allow to boil for at least 10 minutes. Add an additional minute for every 1,000 feet above sea level. Leave the jars in the hot water until you are ready to use them.
I used to heat the lids per the instructions in the book, but according to Ball® it is no longer required.
Preparing for Canning
Filling jars: Depending on the recipe, you may either hot pack or raw pack the food. Jams, jellies, salsas, and sauces are hot packed. Foods that would be delicate after cooking, such as peaches, are generally raw packed.
Headspace: Always follow the instructions in your recipe for headspace, usually 1/4 to 1/2 inch for acid foods, jams, jellies, pickles, and relishes. If you have too little headspace, the food can expand into the lid preventing it from sealing. If you have too much headspace, the jar may not seal because the processing time won’t be long enough.
Air bubbles: Once the food is packed into the jars, you must remove any air bubbles in the jar. Run a nonmetal spatula around the jar between the food and the side of the jar. Do not use metal utensils as these can scratch the hot jars and potentially lead to breakage.
Clean jar rims: Wipe the rim of the jar with a clean, damp cloth. No food particles should remain on the jar rim, as that can prevent the lid from sealing.
Lids: Place the lid on the jar with the sealing compound next to the glass. Screw a band over the lid just until it is finger tight. DO NOT USE FORCE.
Your jars should now be ready for processing.
Always process food immediately after it is packed and the lids and bands have been adjusted. This is important for preventing microorganisms from entering the jars and maintaining the correct temperature for processing.
Processing time: The time will always vary depending on the type of food being canned, the method of packing food into the jars, and the jar size. Check your recipe for the correct processing information.
1. Fill boiling-water canner half full with water. Heat water to a 180° F.
2. Place the canner rack above hot water in the canner.
3. Using the jar lifter, place filled jars onto rack immediately after each jar is filled.
4. After all filled jars are placed on the racks, carefully lower it into the water. The water level must cover the jars and caps by 1 to 2 inches. Add more boiling water if necessary (NOT hot tap water).
5. Put the canner lid in place.
6. Adjust heat to medium-high, bringing the water back up to a hard rolling boil. Reduce heat to maintain a gentle rolling boil throughout the processing period.
7. Set time for the number of minutes required for processing.
8. After the processing period is complete, turn off the heat and remove the canner lid.
9. Using the jar lifter, remove the jars from the canner and set them on a towel to cool. Leave 1 to 2 inches of space between the jars.
10. Allow jars to cool naturally for 12 to 24 hours before checking for a seal. Do not retighten the bands. DO NOT invert the jars, cover them with a cloth or try to cool them quickly.
After the jars have cooled for 12 to 24 hours, test the lids to make sure a vacuum seal has formed. Press the center of the lid to make sure it is concave; then remove the band and try to lift the lid off with your fingertips. Other methods for checking are not as reliable.
If the lid does not seal within 24 hours, the food must be reprocessed or stored in the refrigerator and used within a few days.
Wipe off the lids and jars to remove any food residue.
Label each jar with the date, type, and variety of the product. Store food between 50° and 70° F in a dark place, and use within one year.
- FreshPreserving.com (home of Ball and Kerr)
- The National Center for Home Food Preservation
- University of Maine Cooperative Extension
- Wikipedia – Canning
- Allrecipes – Canning and Preserving
- Ball Complete Book of Home Preserving
- Ball Blue Book of Preserving
- Preserving Summer’s Bounty, by Rodale Food Center and Susan McClure
- The Big Book of Preserving the Harvest, by Carol W. Costenbader
- Canning and Preserving for Dummies, by Karen Ward
- Complete Guide to Home Canning and Preserving, by U.S. Dept. of Agriculture
- Home Canning and Botulism (CDC)
Sources: adapted from the Ball Blue Book (now the Ball Blue Book of Preserving) and The National Center for Home Food Preservation[Disclosure: This blog earns a small commission through affiliate links.]