It’s high season for fresh fruits and vegetables! Gardens, farmers’ markets, and farm stands overflow with produce, sometimes far in excess of what families in the local area can consume fresh. To store your fresh crops, dive into water-bath canning!
Canning at Home: Getting Started
Now’s the time to indulge that interest in the art of “putting food by,” as our ancestors did before the days of year-round, refrigerated supermarket produce. Home canning is experiencing a resurgence of interest for all sorts of reasons.
Simply put, canning works by heating the products inside the jars to a temperature that kills harmful microorganisms and stops enzyme activity in the plant material, then exhausts all the air from the jar, creating a vacuum where nothing can grow and the food won’t spoil. There are two methods for canning: water-bath canning and pressure canning.
If you’re among the folks recently struck by the home canning bug, I recommend starting with water-bath canning, as it’s not as big of an investment. That being said, water-bath canning should be used only for high-acid vegetables and fruits: namely tomatoes (for juice, sauce, paste) and berries (for berry jams and jellies). Their natural acidity—in addition to time in a boiling water bath—helps preserve them safely without the use of high pressure (though you’ll still need to take some precautions).
Corn, beans, winter squash, and other low-acid vegetables require pressure canning to raise the heat inside the jars above boiling, enough to kill harmful bacteria. Pressure canning can be fun and satisfying, but it requires a more expensive outlay, more learning, and more time.
If you’re starting out, you’ll need to assemble some gear. Although you can cut expenses in some ways, food-safety concerns should dictate all of your choices.
Canning Hardware You’ll Need
- A water-bath canner (also called a “boiling water canner,” and essentially a very large stockpot), ideally with a domed lid and a rack to hold the canning jars off the bottom. The canner should be deep enough to submerge your filled jars at least an inch above their tops.
- A rack** that fits inside the canner to keep your jars elevated above the direct heat at the bottom of the kettle. Essential. Don’t allow jars to sit directly on the bottom of your canner, lest they crack from the heat.
- Mason canning jars. These come in many sizes, from four-ounce jelly/baby-food jars, to half-pints, pints, three-quarter quarts, and quarts, in both narrow- and wide-mouth versions. Even if you have access to hundreds of ornamental glass storage jars, recycled pickle and mayonnaise, or the old-fashioned canning jars with wire bails and glass lids that sealed with jar rubbers, don’t use them for canning.
- Single-use metal canning lids that fit your jars. (The science is still incomplete on the safety of reusable lids.) You must use new lids every time you process food. These lids are designed with an inner gasket that softens during processing (heating in the canner), allowing air to escape from the jar during heating, then forming an airtight seal as the jars cool.
- Clean, unrusted, undented metal bands that fit your jars. These screw onto the threaded rims of the jars, holding the lids in place until the products are processed. sealed, and cooled.
- A canning funnel. Ideally stainless steel, this wide-mouthed funnel keeps food from spilling onto the rim of the jar while you’re filling it.
- A stainless steel ladle. You may already have a nice soup ladle that will work well for filling canning jars, but if you’re buying a new one, go for a long-handled model with a pouring spout or rim.
- A jar lifter. These specialized tongs fit around the base of the canning-jar rims to safely grasp and lift hot jars straight up and out of the canner after processing, or to lower them into a canner of boiling water.
- A food mill or strainer. There are many styles and sizes of these devices, designed for mashing soft, cooked foods, and sieving them to remove skins and seeds from the pulp. I’m still using an old hand-cranked Foley Food Mill inherited from my mom, though I also have a modern, heavy-duty food mill that clamps to the countertop and that came with several different-sized screens. I rarely pull it out; in the flurry of summer gardening, harvesting, and preserving, it takes too long to assemble and clean. The old Foley hangs from a hook, ready to go. Plus, it’s reliable (though it takes a little muscle power) and easy to clean.
- A stainless-steel stockpot large enough to hold and cook a big batch of tomatoes, berries, or other products before you funnel them into the canning jars for processing in the canner.
**About those canner racks: Most canning racks have handles that pull up and hang over the rim of the canner, allowing you to lower or raise the entire rack out of the pot. These handles work well for the smaller canners that hold three or four quart jars, but I’ve learned that wrangling them into or out of a larger seven-to-nine-quart canner can be clumsy and downright dangerous.
They’re generally too hot to handle without pot holders, especially when the rack is full of quart jars of, say, just-processed tomato sauce. It’s heavy! You’ll grab one handle, but the other will slip away, or you’ll get one handle up over the rim of the kettle, but miss the other. This tilts the rack, along with the jars, which sometimes slide sideways into the hot water, allowing the product to leak from one or more lids and prevent them from sealing. Full, boiling-hot jars are difficult to extricate when they’re lying on their sides in a foot of hot water.
If you can find handle-less racks to fit your canner, go for it! I simply ignore the handles except for loading and lowering the rack into the hot water when I’m processing pints. I just use the canning tongs to grab each jar and set it into the rack before processing, or lift it straight up and onto a thick kitchen towel to cool after processing.
Where to Find Canning Supplies
Many websites, hardware stores, craft stores, and other retail outlets sell kits that incorporate most of these canning essentials, sometimes along with other handy tools such as magnetic lid lifters, headspace-measuring tools, regular kitchen tongs, bubble removers, and jar scrubbers (though you probably already have kitchen tools that can perform these jobs).
Except for single-use lids, which you should buy new every year, you can reuse mason jars, screw lids, the water-bath canner, food mill, and stockpot for many years. You’ll often find these items in good condition at thrift stores, yard sales, or in the basement of a friend or relative who’s given up on canning. If you find a nice canner with a domed cover but no rack, you can probably find one that fits your kettle in a local hardware store, farm store, or online.
Make sure you check each jar, especially the rim, for small cracks or chips each time you use it. Also, don’t attempt to use a rusty canner; I’ve learned the hard way that rust spots may spring leaks during processing, causing the flame on my gas burner to flicker or dousing it entirely, and leaving me scrambling to find a substitute canning pot.
Use The Right Cooking Surface
Do your water-bath canning on an electric or gas stovetop. No matter what you’ve heard or how cool it sounds, it’s not safe to can in an oven, microwave, or dishwasher. It’s also not safe to can tomatoes and fruit products by simply sterilizing the jars and lids, funneling a boiling-hot product into the jars, and sealing them up. Even if the jars seal well and hold their seal, their contents may not have been heated adequately to prevent microbial growth.
Although some of the new multi-cookers come with a canning feature, the U.S. Department of Agriculture (USDA) says research hasn’t yet determined the safety of these devices for home canning, even for high-acid foods.
Smooth glass stovetops pose another concern for home canners. Some styles of water-bath canners have indented bottoms that prevent heat from the glass top from being adequately distributed during processing. So much of the heat may be reflected from the canner back to the glass, causing the glass to overheat. This may cause the glass to crack, or activate the burner’s shut-off feature, resulting in an underprocessed canner-load.
If you have a smooth, glass cooking surface, the USDA says your best bet is to follow your stove manufacturer’s advice, “because styles of smooth cooktops being manufactured differ in ways that influence suitability for canning.”
Learn More About Canning
Now that you’ve got the supplies and knowledge you need to get started, check out these other canning articles:
Questions? For comprehensive, scientifically-tested recipes and advice, consult the USDA’s free, online Complete Guide to Home Canning.