Basic Canning 101: Your Guide to Canning

Home canning is a food preservation method involving placing food in jars, heating it to a temperature that destroys harmful microorganisms, and sealing. The process also inactivates the enzymes in the food that causes spoilage. When the temperature rises in the jars, the air is driven out. And, when it cools, a vacuum seal is formed, preventing recontamination.

What do I need to can food?

To preserve fruit, vegetables, and meat at home, you need the right tools and canning supplies. Some of what you need is already in your kitchen. Other items may not be necessary but will make the job easier and safer. Either way, if you don’t already have one, you’ll need to purchase a water bath canner or pressure canner, depending on the food you’re preserving. 

Read more for a complete breakdown of all the canning supplies you’ll need.

Water bath canning

Water bath canning is an easy way to preserve jars of homemade jam, pickles, tomato sauce, or other high-acid foods with a pH of 4.6 or less. This method employs a water bath canner and rack or large stockpot. The filled jars sit on the rack at the bottom of the pot, are covered with hot water, and boil for a specified amount of time. The process involves heating a glass jar of food to 212 degrees Fahrenheit and allowing it to cool, which forms a vacuum seal that preserves the contents.

Foods you can preserve by the water bath method include:

• All fruit and fruit juices
• Jam or jelly
• Fruit sauce 
• Pie filling
• Acidified tomatoes
• Tomato-based salsa
• Pickles 
• Relish
• Vinegar-based condiments

Read more for step-by-step instructions to can using the water bath method.

Pressure canning

Pressure canning lets you put up jars of low-acid foods like meat and vegetables. Instead of submerging the jars in a water bath, pressure canning uses less water to produce steam in a specially sealed container that builds up pressure. A boiling water bath reaches a temperature of 212 degrees Fahrenheit. But a pressure canner can reach above 240 degrees, which is required to kill Clostridium botulinum found in low-acid foods. In addition, the process forces air from the jars and forms a vacuum seal that prevents recontamination with harmful microorganisms.

Use a pressure canner for low-acid foods with a pH between 4.6 and 14.0. Or, if you create a recipe of mixed foods, like vegetable soup, pressure canning is always advised. 

Foods you can preserve using a pressure canner include:

• All meat, poultry, and seafood
• All vegetables
• Root crops like beets and potatoes
• Dried beans
• Stocks and broths
• Chili, soup, and stew

Read more for step-by-step instructions to can using the pressure canner method.

Atmospheric steam canning

Steam canning is an alternative to boiling water bath canning for high-acid foods with a pH of 4.6 or lower. Steam canning wasn’t recognized as a safe canning method by the National Center for Home Food Preservation until 2015. But, the steam canner provides several advantages over the water bath method:

• Uses less water
• Less water reaches the processing temperature quicker
• Requires less energy
• The full canner is not as heavy

To safely use a steam canner, place the prepared jars on a rack suspended above a water reservoir. Apply heat to bring the water to a boil, which produces steam. The steam heats the jars to 212 degrees Fahrenheit which drives air from the jars. Then, as they cool, the vacuum seal forms. 

Using a steam canner for low-acid foods such as meat and vegetables is unsafe. But, you can use it for any foods you would water bath can.