How to Can: A Beginner's Guide to Canning and Preserving
Canning was once a literal lifesaver in the days before refrigeration when it was necessary to preserve food to feed families through the long winter months. Now, everyday home cooks are rediscovering how to "can" fruits and vegetables, and even meats and seafood. (By now you've noticed that we say "can" but we're actually using glass jars. You'll get used to it.)
There are groups dedicated to promoting the craft of canning small-batch jams and jellies as well as relishes and chutneys. Enthusiasts share tips on best practices, from the great debate over whether or not to use pectin in preserves, to making suggestions about what foods are prime candidates for water bath canning versus pressure canning. (More on pressure canning in a moment.)
What Is Water Bath Canning?
Water bath canning is a process of preserving prepared food by packing it into jars with self-sealing lids and submerging the jars in boiling water for a set amount of time to create an airtight seal and kill anything that would cause the food to spoil, such as bacteria and enzymes. After the jars are removed from the boiling water, the heat and oxygen escape through the lids, creating a vacuum seal. When the appropriate foods are processed correctly using water bath canning, they can be stored on your pantry shelf for later enjoyment for about a year.
Although water bath canning itself is easy to do, it's important to make sure you do it right. You have to start with the right kind of recipe, boil the right size jar for the correct amount of time, and even adjust the processing time based on your altitude. The National Center for Home Food Preservation is a great resource for home canners.
Not all foods are good candidates for water bath canning. Foods such as jams and jellies with the right amount of acid and sugar in the recipe can successfully use this method. Low acid foods such as green beans and meats, on the other hand, need to be canned using specialty equipment – called a pressure canner – that heats the food to a much higher degree than with water bath canning. Note: pressure canners are NOT the same as pressure cookers, so do not try to use one for pressure canning.
You should begin by deciding what's going into the jars that will be tucked away like gems in your pantry. A bounty of summer fruits and berries are always winners for jams, but there are plenty of ingredients available year-round to fill your shelves. Think winter squash chutney or pickled carrots, cranberry relish, or good ol' sauerkraut. Consider mixing things up with a variety of jar sizes depending on your needs. Large jars are great for favorites that go fast, and small or medium-size jars make for perfect gifts. For best results, follow trusted canning recipes.
Choose the freshest fruits and vegetables available. Going to U-pick farms, farmers' markets, or using fruits and vegetables from your own garden are great ways to ensure freshness. Avoid overripe or under-ripe fruits, which can affect the acidity and stability of the final product. Cucumbers, especially, need to be at their peak of freshness to make great pickles. Always wash the produce and carefully follow the recipe to prepare foods for canning.
Pectin, an essential gelling agent, is found naturally in many fruits. Most jam and jelly recipes call for added pectin, in either liquid or powdered form. There are also special pectins available for making low-sugar preserves. Preserves made without pectin must be cooked longer, depending upon the amount of natural pectin in the fruit.
Acid provides flavor and texture and helps prevent bacterial growth. Acid is also an important part of the fermentation process in making pickles. Lemon juice is typically used as the acid for fruit preserves, while vinegar is more common in vegetable preserves.
The investment in water bath canning supplies puts some people off, but there are now kits designed for beginners looking to test the waters. While sturdy canning kettles last for decades, the next generation canning rack is made from hard silicone and holds three to four jars, which easily fit in a stockpot. (Small batch canning is picking up steam, where you make enough for a quick afternoon project rather than devoting an entire day.) Special canning tongs are helpful for removing jars after they've been processed, but in a pinch, you can wrap rubber bands around a set of regular tongs and remove the jars that way.
- One extra-large pot for sterilizing jars and lids
- Five- or six-quart metal or glazed cast-iron pot
- Jar grabbers
- Metal funnel
- Several metal ladles of different sizes
- Canning jars, lids, and rings
- Paper or cloth towels
In recent years, canning experts have noted that the practice of sterilizing jars and lids is not necessary because any harmful bacteria will be eliminated during the water bath process. You can reuse jars and rings from previous years as long as they are in good condition, but you'll need new lids each time to ensure a good seal. Soak the lids in hot water for at least ten minutes to soften the rubber edge. This will help the lids grip the tops of the jars when you screw on the rings.
Jars should be washed and dried before they're filled. You can run jars through the dishwasher to clean several at a time.
A canning funnel makes the filling step extra neat. Fill the jars, leaving about 1-inch of space near the top, so the contents have room to expand during processing. The amount of "headspace" you need depends upon the recipe, so be sure to follow directions.
Run a thin, non-metallic spatula around the insides of the jars after they have been filled to remove air bubbles, and wipe the rims of the jars with a damp paper towel — any food residue on the rims could prevent a proper seal.
Place the warm lids onto the rims and screw the rings firmly into place, but not as tightly as you can. You can tighten the rings a bit further once the jars have cooled.
Make sure the water level in the kettle will fully cover the tops of the jars by about 1 inch. Bring the water to a rolling boil and lower the jars nestled in the rack into the water and cover the kettle. Set the timer for 10 minutes for most jams, jellies, and chutneys, slightly longer for fruits and pickles, or follow the instructions in the recipe.
Once the processed jars have been removed from the water bath canner, let them sit, undisturbed, for at least an hour. As the jars cool, the lids will become sunken in the center and you may hear a little "ping," indicating the lids have sealed. If they don't seal, refrigerate the preserved food and eat within two weeks, or you can try using another lid and going through the water bath process again.
Now, it's time to stand back and admire your good work. There's nothing quite like the sense of accomplishment that comes from creating something delicious that you can share and enjoy months later. Be sure to label your babies, and include a canning date. There are tons of pretty labels to make those jars stand out, and some are even designed for easy removal, so you can fill them up again.
Video: See how to make Green Tomato Relish
Get the Recipe: Green Tomato Relish
Storing Your Jars
Store your jars away from direct sunlight in a cool, dry place. Processed foods typically have a shelf life of a year, although many items may not spoil for longer periods. If you see mold, discoloration, or smell something off, discard the food immediately. But don't just trust your nose — some bacteria can produce toxins that are undetectable by sight or smell, so if a jar's seal has been compromised, throw it away. If in doubt, throw it out.