How to Process Foods in a Water Bath Canner

Canned strawberry jam

The Spruce / Sean Timberlake

Boiling water bath canning is the easiest way to make shelf-stable jams and pickles right in your own home. 

It’s important to note that only high-acid foods can be preserved by water bath canning. This includes most fruit preserves, including jams, jellies, and fruit canned in syrup, and many pickles. However, always make sure you are using a safe, tested recipe from a reliable source, such as the National Center for Home Food Preservation. Non-acidic vegetables, meat including poultry and fish, and soup stocks (yes, even vegetable stock) must be processed in a pressure canner, not a boiling water bath.

Basic Equipment and Setup

Canning equipment on a towel
The Spruce / Sean Timberlake

Though ready-made canning kits are often available right in hardware stores or for sale online, you may have many of the necessary pieces of equipment already in your kitchen. If so, you can selectively buy the other pieces and possibly save money.

Basic Equipment

  • A large, tall pot
  • A rack to fit inside the pot
  • Canning jars with two-piece lids (available at Amazon)
  • A ladle
  • A canning funnel
  • A timer
  • A jar lifter (available at Amazon) or tongs
  • A clean spatula or chopstick
  • A moist, clean towel or paper towel

Optional Equipment

  • A lid caddy (pictured)
  • A magnetic lid wand (available at Amazon
  • A canning rack with handles
  • A stovetop or electric kettle

Getting Started

Place a rack in the bottom of a tall pot, like a stockpot or a lobster pot. The rack keeps the bases of the jars off the bottom of the pan, allowing evaporating water to escape around the jars and preventing them from rattling against each other, which could cause breakage.

Add enough water to cover the jars you are going to process by at least one inch above the lids.

Turn on the heat. If raw-packing, bring the water to 140 F; if hot-packing, bring the water to 180 F. You can do this while you are preparing your foods to be canned.

Fill the Jars

Filling the jars with strawberry jam
The Spruce / Sean Timberlake

Before beginning, check all jar rims for chips or other imperfections. Do not use those jars when canning. Make sure you are using new lids that have not been processed previously. Rings can be reused.

If the manufacturer of your jars and lids instructs you to, heat the jars in the water bath, and lids in a separate container of hot water. Ball Mason Jars recently changed their recommendation, saying this is not necessary for their products. For Ball and Kerr products, wash your jars and lids with hot, soapy water just before filling, and rinse and dry well. Alternatively, run the jars (but not the lids) through a cycle in the dishwasher.

Working swiftly, use a ladle to fill your canning jars with the recipe you have made.

Leave an appropriate amount of headspace, usually between 1/4 inch and 1 inch, between the top of the food and the rim of the jars. This should be specified in the recipe.

Run a clean spatula or chopstick around the interior of the jars to release any air bubbles that may be trapped.

Wipe any trace of food off the rims with a clean, moist towel or paper towel. This allows better contact of the lid and the jar, ensuring a better seal.

Apply the Lids and Rings

Applying the Lids on the canning jars
The Spruce / Sean Timberlake

Place the round canning lids on the jars; this is where the magnetic lid wand comes in handy, allowing you to nab them one at a time. Screw on the bands onto the jars until just finger-tight. You want them to be securely screwed down onto the jars, but not so tight that air cannot escape during the canning process.

Process the Jars

Lowering a jar into the boiling water using a jar lifter
The Spruce / Sean Timberlake

If you have a rack with handles, load the jars into the rack and lower it into the water bath. Otherwise, Carefully lower your filled jars into the boiling water using a jar lifter or tongs, being careful to keep the jars vertical so as not to let the food make contact with the rim of the jars. There should be at least 1 inch of water above the top of the jars. If there is not, add more hot water until the level is sufficient. This is where the kettle comes in handy.

There should be at least 1/2 inch of space between the jars.

Turn up the heat, and bring the water to a full rolling boil. Put the lid on the pot.

Start timing according to the recipe you are following. Canning recipes that call for a boiling water bath will include an instruction like "process for 10 minutes." The processing time doesn't start until after you've put the jars of food into the water and the water has returned to a full boil. If the water is boiling too vigorously, reduce the heat until it comes down to a more gentle but still full boil.

Let the Jars Cool Down

Lifting the jar out of the boiling water to cool on a rack
The Spruce / Sean Timberlake

When the processing time is up, turn off the heat, and let the jars settle for five minutes.

Remove the jars in their rack or using a jar lifter or tongs when the processing time is complete. Lift the jars vertically, being careful not to tilt them, as this can cause the food inside to interfere with the seal of the lid. Transfer them to a cooling rack or towels on a counter, allowing 1 inch between jars. Be careful not to set them directly ​on counters or in a drafty place, which may cause temperature shock and can cause breakage.

Let them cool undisturbed for 12 to 14 hours. Do not disturb the jars or lids during this time. You will hear a pinging sound as the lids flex and seal. This is normal.

Test the Lids, and Store Your Jars

Testing the lids of canning jars to confirm they are sealed
The Spruce / Leda Meredith

After the cooling period, test whether the jars have sealed correctly by pressing down on the lids. If sealed, they won't wiggle and will feel solid when you press on them.

Remove the rings. Test the seal again by gently lifting the jars from the edge of the rim. You should be able to lift the jar from the tension of the lid alone. If any lids fail, refrigerate the contents and consume them promptly. Alternatively, if no more than 24 hours have gone by, the contents can be reprocessed using the same method with a clean lid and, if necessary, a new jar.

Wash or wipe down your jars with a moist cloth to remove any sugars or other residues from the canning process. Store them in a cool, dark place for up to one year.