Home canning is a passport to all sorts of food preservation adventures. From marmalade to tart and spicy salsa, canning puts a satisfying roaster of homemade condiments on your pantry shelves.
The most common form of home canning is water bath canning—probably because it’s the most straightforward. It’s not rocket science, but there are lots of steps and required equipment to get familiar with. Stick around and we’ll walk you through it so you can can with confidence.
A Bit of Canning History
Preserving food has been around as long as humans have hunted and gathered. Compared to smoking, curing, and fermentation, canning is quite new. The process was initially developed during the Napoleonic Wars to feed a multitude of troops on the move. The concept of portable, perishable rations for conflict flies in the face of many cozy DIY notions we have of home canning in our time, but the functionality is the same in either scenario: sealing food in a sterilized jar keeps bacteria out, and that in turn keeps food from spoiling.
Water Bath Canning vs. Pressure Canning
There are two types of home canning.
- Water bath canning is only for high-acid foods (like vinegar pickles) or high-sugar foods (like jams and jellies). The “water bath” in question is simply a pot of boiling water.
- Pressure canning is done in a pressure canner, a specialized pressure cooker
(the National Center for Food Preservation recommends a capacity of 16 quarts or larger). Low-acid and low-sugar foods such as stocks and beans must be pressure canned for safe canning. Pressure canning is its own beast, so we’re not discussing it here.
Equipment for Water Bath Canning
- Canner: As technical as this sounds, a canner is simply a large stockpot. You can buy these specifically for canning; often they are enameled steel and relatively affordable. A regular stockpot works for water bath canning, but you need to make sure a canning rack can fit in the bottom.
- Canning rack: This is a round rack that sits in the bottom of your canner. It elevates the jars a bit so the boiling water can circulate underneath them. It also keeps the jars from jiggling around. When you buy a canner, it almost always comes with a canning rack that fits in the bottom neatly. In a pinch, you can use a round cooling rack, or the steamer rack from an Instant Pot.
- Canning jars: Use only jars made for canning. The cute jar that once held your imported Dijon mustard might crack in your water bath, making a big mess (trust me, I know from experience). Save it for storing leftover salad dressing.
- Canning lids: Most lids for canning sold in America are two-piece, with a flat lid and a threaded band that secures it in place. You can re-use the rings, but the National Center for Home Food Preservation recommends only using the lids once.
- Ladle: Any regular old ladle will work for filling your jars with hot preserves or brine.
- Canning funnel: A tool you can skip, but it makes quick work of filling your jars, and means you don’t have as much goop to wipe from the rims of your jars before you screw the lids on. A canning funnel is useful for filling jars for non-canning purposes, too. Worth it!
- Jar lifters: This specialized tool makes lifting jars out of your canner full of boiling water a cinch. You can use regular kitchen tongs to grapple the jars out, but jar lifters are easier and a lot safer for you. For your first go, you can put rubber bands around the ends of regular kitchen tongs for a better grip, but really, it’s smarter to just bite the bullet and buy jar lifters.
- Clean cloth kitchen towels: Keep lots of these on hand. Paper towels will work, but cloth towels are more absorbent and just feel nicer.
You can get canning kits that include most of these tools for $17 to $75. Here’s one I recommend. Feel free to borrow canning equipment from a friend if the cost per kit is too much of a commitment.
How to Water Bath Can: Step by Step
Gather your equipment all in one spot. I like a sheet pan with a cloth towel and lay a ladle, jar lifters, tongs, a metal cooking spoon, canning funnel, extra towels, lids and bands, and of course, the canning jars themselves. Phew!
Clean your workspace. It’s a lot easier to can when there’s no clutter to rearrange at the last minute
Rinse the jars, then put them in the canner on the canning rack.
Fill the canner with enough hot water to cover the jars by at least 1 inch.
Put on the lid and bring to a boil over high heat.
As the water comes to a boil, wash the lids and bands in hot, soapy water. Dry well. Go ahead and get started on whatever you’ll be canning. (Jar lids used to need to be warmed in a hot—not boiling—water bath, but that’s not the case now.
Is that water boiling now? Yes? Great. Boil the jars for 10 minutes to sterilize them. Once they are sterilized, reduce the heat so the water is at a low simmer. It’s important that the jars be hot when you fill them. Keep covered.
When it’s time to fill them, lift the jars from the canner using jar lifters or regular tongs and dump the hot water from each jar back into the canner. Line the hot, empty jars up on one of the towels you have ready.
Fill the jars using the handy canning funnel. Your recipe will tell you how much headspace to leave (headspace is the empty space between the rim of the jar and whatever you are canning).
Wipe the rims: If any of the food you’re canning got on the rims of your jars, wipe it off with a clean, damp towel.
Put on the lids: Lay the lids on the jars, then screw on the bands fingertip-tight. This means not too tight and not too loose.
Using the jar lifters, lower the jars into the water bath canner. Add more water if needed so the jars are totally submerged by at least 1 inch of water. Raise the heat to high. Once the water comes to a rolling boil, begin your timer, and process the jars in the water bath as long as the recipe says (adjust for altitude, if necessary; see note below). This is called the processing time, and it’s not the same for every recipe.
Remove the jars: When the processing time is up, use the jar lifters to fish the jars out of the canner. Set them on a cloth towel on your counter.
Check for a seal: As the jars cool, the tops should seal. Sometimes this happens right away, with an audible pop. Sometimes they make no sound at all and take 20 minutes, or even a few hours. You can tell a jar is sealed when you tap firmly on the lid and hear a dull thump. Lids that aren’t sealed will make a metallic ping.
Any jars that didn’t seal within 12 hours can be added back to the water bath and processed again. If your jars refuse to seal, let them cool and store them in the freezer (which is okay for jams) or refrigerator (for jams or pickles). As long as you don’t stick dirty fingers or spoons in there, open jars of jam will keep in the refrigerator up to 3 months, maybe even longer; same goes for pickles.
When the jars are completely cool, unscrew the bands, which tend to trap water. Dry off the bands and jars, if needed, and then screw the bands back on.
For long-term storage, it’s fine to leave the bands off, especially if you live in a humid climate or store jars in a damp place (the bands can rust over time). Just screw the bands on as needed as you open the jars or give them away.
Label and date your jars.
How Long Do Home-Canned Jars Keep?
Most canned goods have the best flavor when consumed within a year, but they’ll remain safe for consumption a lot longer than that. I have jars of jam going on 4 years that are still plenty good. Even so, a rule of thumb is to consume home-canned goods within 1 year.
How Long to Water Bath Can
Your recipe will tell you the processing time. It is often different for half-pint and pint jars or quarts. If your recipe didn’t tell you the processing time, search for a similar recipe on the National Center for Home Food Preservation’s website and use that processing time.
Water Bath Canning Times at Altitude
If you live at higher elevation (1,000 feet or 305 meters) above sea level, you’ll need to lengthen your processing time to account for the lower temperature of boiling water at elevation. For a primer on that, visit this post from our friend Marisa McClellan at Food in Jars.
What Is Headspace?
The gap between the rim of the jar and the food you’re canning is called the headspace. Different recipes call for different headspaces because certain foods expand during the canning process. Most jam and jelly recipes call for 1/4-inch headspace. Many pickle recipes, meanwhile, call for 1/2-inch headspace.
Some canning funnels even have hash marks to indicate headspace levels.
Awesome News About Canning Lids
Older canning recipes call for keeping the lids (the flat metal part, not the band) in their own pan of near-boiling water until it’s time to put them on the jars—a step that was, quite frankly, a pain in the butt.
Great news! This step is now unnecessary for most products made by Newell, including Ball and Kerr lids. You can read the scoop from their website, but in essence, their testing determined that preheating the lids wasn’t necessary. In fact, subjecting them to boiling water prior to canning may even cause a seal to fail.
Washing lids in hot, soapy water, rinsing, and then drying them well is the new protocol. Many recipes in cookbooks and online aren’t updated with this info yet (I guess there wasn’t a sweeping press release in 2014 about new developments in canning lid sealing compounds), but you can—and should—simply wash the lids in how, soapy water and skip the boiling water step for Ball and Kerr lids.
Using different lids? Go with the recommendations on the package.