Canning 101: How to Use Water Bath and Pressure Canners
Preserving the harvest is easier than you thought.
Canning is a method to preserve food using boiling water or steam to create an airtight seal inside of a glass jar. It is a simple process that is often made out to be much more complicated than it actually is. That’s because it is often conflated with other aspects of food preservation, such as pickling vegetables or making fruit preserves. Canning is simply the final step in preserving these items – the complicated part is mastering all the ways that food can be processed before it is canned and put on the pantry shelf. There is tremendous variation in the recipes for foods that are canned and it is important to follow them precisely – especially when it comes to ingredients like pectin, sugar, citric acid, salt, and vinegar that play a role in preservation.
When it comes to canning technique, the main variable is which type of canning device will be used. Water bath canners – essentially a large pot with a metal rack on the bottom to support Mason jars – are suitable for fruits (which includes tomatoes). Here’s a version we like. Canning vegetables and animal products require a pressure canner (we recommend this version) to reach the temperature necessary to preserve these foods safely. Pressure canners cost a bit more than water bath canners, but are worthwhile given that botulism, a lethal disease associated with canned foods, can only be eliminated by temperatures above the boiling point of water in canned vegetables and animal products. (Note: The inherent acidity of fruits helps to prevent botulism, so there is no need for the extra heat in their case. Use a pressure canner for recipes where fruits and vegetables are mixed.)
[Canning] is a simple process that is often made out to be much more complicated than it actually is.
Other than that, the canning process varies only slightly with different types of foods, and this information will be included in the canning recipe. For both methods, you’ll need Mason jars (with lids and bands), a jar funnel, jar tongs, oven mitts, and a plastic spatula. The rubber gasket on Mason jar lids is the key component responsible for sealing out air and preventing spoilage – they are only designed to be used once, so pick up an extra pack of lids for each new round of canning. The threaded metal bands that hold the lids in place may be used over and over, however.
Water Bath Canning for Fruits
- Place the jar rack on the bottom of the pot and arrange the mason jars on top of the rack.
- Fill the pot (with the jars inside; no lids), with water at least 1 inch above the top of the jars.
- Put the pot on the stove, cover it with a lid and turn the burner on high. Use the time it takes for the water to boil to prepare the food that will be canned.
- Once the water has boiled, pull the jars out with the tongs, empty the water they contain and place them on a towel on the counter. Retain the water in the pot.
- Fill the jars with the food product using the funnel, if needed. The recipe should indicate how much space to leave at the top of the jar. (A quarter or half inch is typical – smooth-textured jams and preserves require less, while chunky fruits and vegetable suspended in liquid require more).
- Stir the contents of the jar to release any air bubbles that may be trapped in the jar.
- Wipe the rim of the jar clean with a damp cloth to ensure a good seal with the lid.
- Place the lid on top and screw the band snugly into place.
- Lower the jars into the pot of water. Use a glass heat-proof measuring cup if you need to scoop out excess water to prevent the pot from overflowing.
- Cover the pot, bring the water back to boiling, and set a timer for the length of time indicated by the canning recipe you are following.
- Once the timer goes off, remove the jars and put them onto towel-lined countertop where they must remain undisturbed for at least 12 hours.
After the jars have cooled, confirm that they have been sealed by pressing into the lid with your finger. If the lid can be depressed and pops back up, it is not properly sealed. The lid should not move when pushed if the process was successful. You can also take off the bands and lift up the jars by the edge of the lid to test them – they should remain firmly in place. If the seal is not successful on any of the jars, repeat the canning process or just store them in the refrigerator for immediate consumption.
Pressure Canning for Vegetables and Animal Products
Pressure canners vary by manufacturer, but the process for using them is similar to water bath canning. The main difference is that the jars will sit in just a few inches of water, rather than being submerged. There is a vent on top of the canning pot that allows steam to escape, which needs to be left open for the first ten minutes of boiling (to allow the air to escape) and then closed (to keep the steam in).
For foods that need to be preserved with a pressure canner, the canning recipe should indicate the amount of time to leave the jars in the canner, as well as the amount of pressure that is necessary (in PSI, or pounds per square inch). Pressure canners are outfitted with pressure gauges and the heat can be raised or lowered to achieve the correct pressure level.
Check the instructions that come with the device for more details on how to operate it.
A Few Final Details
Elevation above sea level affects the boiling time needed to seal jars in a water bath canner and the pressure required for canning with a pressure canner. Recipes give the time and pressure for sea level, so use a conversion chart to find the appropriate numbers for the altitude where you live.
Successfully canned foods resist spoilage and retain their color, nutrients, and flavor for a year or more when stored in a cool dry place. It is important, however, to start with only the freshest ingredients – avoid using old, soft, diseased, or damaged produce. Always check the lids before using a canned product and discard any that are no longer sealed.
Follow us
Republish!
Republish our articles for free, online or in print, under a Creative Commons license.
Republish this article
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.
Want to republish a Modern Farmer story?
We are happy for Modern Farmer stories to be shared, and encourage you to republish our articles for your audience. When doing so, we ask that you follow these guidelines:
Please credit us and our writers
For the author byline, please use “Author Name, Modern Farmer.” At the top of our stories, if on the web, please include this text and link: “This story was originally published by Modern Farmer.”
Please make sure to include a link back to either our home page or the article URL.
At the bottom of the story, please include the following text:
“Modern Farmer is a nonprofit initiative dedicated to raising awareness and catalyzing action at the intersection of food, agriculture, and society. Read more at <link>Modern Farmer</link>.”
Use our widget
We’d like to be able to track our stories, so we ask that if you republish our content, you do so using our widget (located on the left hand side of the article). The HTML code has a built-in tracker that tells us the data and domain where the story was published, as well as view counts.
Check the image requirements
It’s your responsibility to confirm you're licensed to republish images in our articles. Some images, such as those from commercial providers, don't allow their images to be republished without permission or payment. Copyright terms are generally listed in the image caption and attribution. You are welcome to omit our images or substitute with your own. Charts and interactive graphics follow the same rules.
Don’t change too much. Or, ask us first.
Articles must be republished in their entirety. It’s okay to change references to time (“today” to “yesterday”) or location (“Iowa City, IA” to “here”). But please keep everything else the same.
If you feel strongly that a more material edit needs to be made, get in touch with us at [email protected]. We’re happy to discuss it with the original author, but we must have prior approval for changes before publication.
Special cases
-
Extracts. You may run the first few lines or paragraphs of the article and then say: “Read the full article at Modern Farmer” with a link back to the original article.
-
Quotes. You may quote authors provided you include a link back to the article URL.
-
Translations. These require writer approval. To inquire about translation of a Modern Farmer article, contact us at [email protected]
-
Signed consent / copyright release forms. These are not required, provided you are following these guidelines.
-
Print. Articles can be republished in print under these same rules, with the exception that you do not need to include the links.
Tag us
When sharing the story on social media, please tag us using the following: - Twitter (@ModFarm) - Facebook (@ModernFarmerMedia) - Instagram (@modfarm)
Use our content respectfully
Modern Farmer is a nonprofit and as such we share our content for free and in good faith in order to reach new audiences. Respectfully,
-
No selling ads against our stories. It’s okay to put our stories on pages with ads.
-
Don’t republish our material wholesale, or automatically; you need to select stories to be republished individually.
-
You have no rights to sell, license, syndicate, or otherwise represent yourself as the authorized owner of our material to any third parties. This means that you cannot actively publish or submit our work for syndication to third party platforms or apps like Apple News or Google News. We understand that publishers cannot fully control when certain third parties automatically summarize or crawl content from publishers’ own sites.
Keep in touch
We want to hear from you if you love Modern Farmer content, have a collaboration idea, or anything else to share. As a nonprofit outlet, we work in service of our community and are always open to comments, feedback, and ideas. Contact us at [email protected].Canning 101: How to Use Water Bath and Pressure Canners
by Brian Barth, Modern Farmer
September 9, 2015
Modern Farmer Weekly
Solutions Hub
Innovations, ideas and inspiration. Actionable solutions for a resilient food system.
ExploreExplore other topics
Share With Us
We want to hear from Modern Farmer readers who have thoughtful commentary, actionable solutions, or helpful ideas to share.
Submit
Very good article steps for Water Bath Canning for Fruits is so useful. I would like to implement it.
United States of America was actually constructed because of migrants arriving to this very nation looking for a improved living. A life of freedom with possibilities to form a new world. Often times we do not recognize how significantly the ripples of each of choices go. The government close down has a ripple effect on the overall economy experienced by millions of Americans and small enterprise owners. America’s most important advantage is faith! The administration close down is taking hope from Entrepreneurs. Founded on the principle that America could be better and that we can be afforded the opportunities that… Read more »