Boiling Water Bath Canning Basics

Here is a list of basic equipment and how-to to get you started canning using the boiling water bath process.

The boiling water bath process is appropriate for high-acid foods only.  This includes most fruit as well as anything pickled in vinegar.  Always use a trusted guide such as these from Bernardin or the Ball Blue Book Guide to Preserving and follow a recipe or process developed specifically for water bath canning.

The minimum equipment you will need are canning jars with lids and a large deep pot to hold enough boiling water to cover those jars by about 1 inch.


This is a standard blue enamel canner available at most large hardware and housewares stores (Canadian Tire is a great source for them as well as jars, lids and most other canning equipment and supplies!)


Clockwise from top left are some other things that will make your canning life much easier:  small saucepan for hot water to soften the sealing gum on the lids, Mason jars of various sizes depending on what you are canning, a ladle, a wide-mouth funnel, a magnetic-tipped wand for picking up lids (not exactly essential, but really handy!), a good paring knife, jar-lifting tongs, and finally snap lids and their rings.

The funnel, magnetic wand and the tongs are available as part of a tool kit, available on both the Bernardin and Ball websites as well as at Canadian Tire.



Jars come in a variety of shapes and sizes in both the standard opening (72mm) and "wide-mouth" (80mm) formats.  The most common jar sizes are half-pint (1 cup/250ml), pint (2 cups/500ml) and quart (4 cups/1 litre).  Larger and smaller sizes are available, but be aware of the capacity of your canner when acquiring jars.



The standard canning lid is known as a "snap" lid (possibly because the lid is snapped down via suction to seal the jar) and consists of a metal disc and a metal ring that is threaded to screw on to a jar.  The metal disc has a small raised button at its center and a ring of red rubberized gum running around the edge of its underside.  When canning, this gum is softened before applying to hot filled jars to aid it in gripping the top edge of the jar and creating a seal.  While in the canner, the contents of the jars are brought to a boil creating steam under the lid which escapes creating a vacuum.  When the jars have finished processing and are cooling, the vacuum under the lid will draw the disc downwards, "snapping" it with an audible "pop" or "ping".  This indicates that the jar has successfully sealed and is shelf-stable.  If you look carefully, the small raised button in the center of the metal disc should now be a concave divot and if you press on the lid with your finger there should be no movement -- the lid should feel solid.  Snap lids are available in 72mm and 80mm sizes to fit standard or wide-mouth jars respectively.


To start, wash jars and rings in warm soapy water, rinse and let drain for a moment.  Meanwhile, put the rack inside the canner.  Add about 1 cup of white vinegar to the canner to eliminate mineral deposits on the inside of the canner as well as the jars.  Place the jars upright into the rack and add the rings.  Fill the jars and the canner with tap water until the jars are covered with an inch of water.  Put the canner on high heat and bring to a boil while you start your recipe.


To sterilize the jars, they need to boil for at least 10 minutes.  It will take some time for the canner to come to a boil, so depending on the complexity of your recipe, you may or may not be ready when the jars are.   The heat under the canner can be turned down after boiling for 10 minutes and the jars can be kept at a simmer if you need time to complete your recipe.  If you do turn down the heat, just remember to return it to high once you've loaded the canner with filled jars so it can come back up to boiling.  With practice you'll figure out when to start what so you can be ready to fill your jars as soon as your recipe is ready.







Use the tongs to remove and empty the sterilized jars and rings.














Place the sterilized jars and rings on a clean tea towel.














Use the funnel and a ladle to fill the jars, usually leaving a 1/2 inch space at the top.  This is known as "headspace" and is necessary to allow steam to develop under the lid during the boiling water bath. The steam forces out the air creating a vacuum which sucks the lid down onto the jar as it cools thereby sealing it and making the jar safe to store without refrigerating it.









To help the lids fully seal, wipe the rims of the jars with a clean dishcloth or paper towel after filling to remove any food residue that may have splashed up.












Keep the lids simmering (not boiling) in hot water throughout the canning process.  This softens the band of red rubber gum running around the perimeter of the underside of the lid and helps it to seal to the jar.  Using the magnetized wand makes it easy to retrieve the lids from the hot water.











Center the lid on the jar.













Apply the ring.














Screw the ring down just until resistance is met. This is known as "finger-tight".  Don't over-tighten as we need to leave space for steam and air to escape from under the lid during the water bath.












Use the tongs to place the filled jars back in the canner.












Ensure that the water covers the tops of the jars by about 1 inch. Cover the canner and bring the water back up to a full rolling boil. Start counting time only once a full rolling boil has been reached and maintain the full rolling boil for the full processing time stated in the recipe.

Most canning recipes state canning times for altitudes up to 1,000 ft. If you live in a high-altitude area (i.e. higher than 1,000 ft.) you will need to adjust your canning times accordingly. If you don't know the altitude where you are canning, you can check here for many Canadian locations, or check a local map.

When the time is up, turn off the heat and let the canner sit undisturbed for 10 minutes or so. This allows things to settle and helps to prevent siphoning. When ready, use the tongs to remove the jars to a clean tea towel and listen for the "ping" of the lids sealing. You should begin hearing some within a few minutes of removing the jars from the canner but don't panic if you don't. Some may have sealed inside the canner while it was sitting after the heat was turned off. Some others may take a little longer. Leave the jars to cool undisturbed on the tea towel overnight.

The next day, check the seals.  Press down on the center of each lid. If it feels solid and does not move, the jar has sealed.  If it bounces or moves it did not seal. As a secondary check, remove the ring and, grasping the edges of the lid with your fingertips, gently lift the jar an inch or so up off the tea towel. If the lid stays on and feels solid, the jar is sealed. If the lid pops off, then obviously it didn't seal.

Jars that did not seal may be re-processed in a boiling water bath, but fresh lids must be used. A lid that has been used will most likely not seal again. Prepare another water bath, soften some new lids in hot water and re-process as above starting from the point where you just filled the jars.

Alternately, unsealed jars may be refrigerated and used with a week or so. 

Sealed jars are shelf stable and should be stored away from light and heat.  Cupboards, closets, basements are all excellent choices.  Jars are at their best up to a year after canning, but do last much longer, however taste and colour will begin to fade over time.