The canning process has three main variations: water bath, pasteurize, and pressure. The USDA’s Complete Guide to Home Canning, 2015 revision, is the ultimate source for government-approved canning guidelines, and the steps given here are condensed versions of those processes. As you try your hand at the recipes on this site, you’ll frequently be referred back to this page for the best way to process a particular fruit or vegetable for long-term canning storage.
Water-bath processing is the easiest way to can high-acid foods. Low-acid foods, including most vegetables, must be pickled or otherwise acidified if you want to run them through a water bath; otherwise, they must be processed in a pressure canner.
- Set the canning rack in the bottom of the canning kettle, fill it halfway with water, and bring it to nearly a boil.
- Wash the jars, rings, and lids. Keep the jars hot until you are ready to fill them. Check the manufacturer’s directions for the lids; some brands need to be warmed before use.
- Pack or ladle prepared food into each jar, using a wide-mouth funnel to reduce the mess and leaving the headspace indicated in the recipe.
- Insert a chopstick down the inner edge of the jar, pressing it up and down as you turn the jar to remove air bubbles, and then use a damp cloth or paper towel to wipe the rim clean.
- Set the lid on the jar, and screw on the ring so that it is just finger tight; overtightening prevents air from escaping as the jar seals and can cause the lids to buckle.
- Add each jar to the kettle using a jar lifter. Repeat the process with each jar until the canner is full, adding more hot water if needed until there is at least 1 inch of water over the jars.
- Cover the kettle, turn the heat to high, and wait for the water to reach a full boil. Once boiling, set the timer as specified in the recipe, adding your altitude adjustment.
- Remove the jars from the canner, again using a jar lifter to transfer them from the kettle to a towel spread on a flat surface. Leave the jars to cool for at least 12 hours; the lids will ping as they seal.
- After 12 hours, remove and wash the rings and wipe down the jars with a damp cloth. Label each jar, listing at least the contents and date.
- Test the seal on each jar by pressing the center of the lid. If the lid flexes, replace the ring and put the unsealed jar in the refrigerator for immediate use. If the jar is sealed, store it in a cool, dark, dry place; store the rings separately.
Pasteurizing is similar to water-bath processing; the primary differences are temperature and time. For a traditional water bath, the water must be brought to a full, rolling boil. When pasteurizing, the water is kept between 180°F and 185°F. Water-bath processing times vary, depending on what you are processing and where you live. When pasteurizing, 30 minutes creates a safe seal.
Pasteurizing is strictly for certain types of pickles. Pickled foods that are meant to be crisp and firm often suffer when dropped into boiling water. By lowering the temperature for a longer period, pickles stay firm yet unspoiled. The USDA suggests it for a variety of pickled cucumbers and zucchini. On this blog, the recipe will mention pasteurization when it is an option.
- Prepare to can as you would for a boiling water bath: Gather and check your equipment, heat the kettle of water, and then clean, heat, fill, and cap the jars.
- Check the water’s temperature with a thermometer, ensuring that it is holding steady between 180°F and 185°F.
- Cover the canner and set the timer for 30 minutes, checking regularly to ensure the temperature does not drop. For every minute it spends below 180°F, add a minute to your timer.
- Remove the jars from the canner and let them cool as you would with a boiling water bath before cleaning, labeling, testing, and storing.
You won’t find any recipes on this blog that require a pressure canner for a simple reason: I don’t use one. The full explanation is much longer (and will likely be the topic of a future blog post), but the essence is that I prefer the flavor and texture that results from another processing technique to that of almost any food run through a pressure canner. If you are interested in learning about pressure canning, I highly recommend starting with the USDA’s Complete Guide to Home Canning, 2015 revision; Guide 1 outlines the basics, and later guides give further details.