If you’re trying to live a sustainable lifestyle, one of the best ways to reduce your dependence on packaged foods (thereby reducing the amount of waste you accumulate in addition to other concerns) is to grow your own vegetables. The problem is that some of the veggies you want to grow may not be available all year. To deal with this, women used to preserve foods so they’d be available all year long. It’s easy to do, though a bit time consuming.
How not to can foods
Before we talk about canning, we should explore the methods you should never try. Methods like the aspirin method, the microwave method, dishwasher method and oven canning just don’t ensure all potential forms of bacteria are gone. You should also avoid the open-kettle method and steam canners and electric water baths, which haven’t been fully researched yet. And while canning powders seem like a great idea, they’re not good preservatives and don’t replace doing things the old-fashioned way.
Spoiled canned food can lead to uncomfortable (and potentially fatal) forms of food poisoning. You can’t always tell when these processes have started. (Note: Removing any mold that's formed just gets rid of the mold — it doesn't eliminate the bacteria living in the canned food that may not have caused mold, yet.)
For more information on why these methods don’t work, check out this publication by Ohio State University. We also suggest you download the free USDA Complete Guide to Home Canning, a 196-page source for information about all types of canning, including safe process times for just about anything you could decide to can.
Choosing a pressure canner
The only safe way to preserve food is to use a pressure canner. Boiling water just doesn’t get hot enough. Also, don't confuse a pressure canner with a pressure cooker, which can cause your jars to explode!
We recommend choosing a pressure canner with an automatic pressure regulator so you don’t have to keep such a close eye on it yourself. While they’re more expensive, you can purchase pressure canners that double as pressure cookers. If you do that, avoid one made of aluminum, which can oxidize and make food taste strange. Stick with a stainless steel model. The extra money is worth it. Make sure it has safety features like an emergency release.
Safely canning food
- Pressure canner
- Mason jars and lids
- A canning funnel
- Preservatives (sugar, salt, acids like lemon juice or ascorbic acid)
- Plastic canning knife
- 3 Clean dish towels
- Magnetic lid wand or tongs
- Wash your hands thoroughly with antibacterial soap (singing "Yankee Doodle" all the way through should be long enough). If you do another task while cooking (or sneeze or go to the bathroom), do it again.
- Even if you’re using a recipe, which we recommend, check the recipe carefully against current USDA canning guidelines to make sure it’s accurate in terms of safety.
- Sterilize your Mason jars and lids (both parts) in boiling water for at least 10 minutes. Use the tongs (or for the metal, a magnetic lid wand) to remove them, turning them upside down on a clean towel to drain and place another clean towel on top of them until you’re ready to use them. (Add an additional minute of boiling time per 1,000 feet if you’re at a high altitude.)
- Peel and cut the fruit or vegetable you’re going to can. If you’re using an ingredient that has a skin, you can boil them, remove them from the boiling water and place them in an ice bath until they’re cool enough to touch. Then the skins just peel off. Remove any pits, stems, cores and anything else that’s inedible before canning.
- Prepare the vegetables or fruits according to your recipe.
- Pour your finished fruit or vegetable into the Mason jar, leaving a little room at the top (called “head space”) — the recipe will tell you how much head space to leave. You can carefully arrange the food if you’d like it to look nice, but that’s not necessary.
- Add the liquid called for by the recipe. Use the plastic knife to remove any air bubbles by running along the sides and gently pressing the food or wiggling the knife.
- Use the third clean dish towel to thoroughly wipe the rims (including the threads) clean. Don’t forget the top rim.
- Place the lid on the jar and tighten it.
- Follow your pressure canner's instructions carefully, as not all models work the same way. In general, you’ll add water to the canner, add the jars, close the lid and bring it up to temperature for at least 10 minutes. Close the vent port or petcock so it will pressurize (takes around 3 to 5 minutes). When the time is up, turn off the heat and allow it to depressurize. Don’t force-cool it, as this will interrupt the preservation process and could prevent it from properly killing bacteria.