For low-acid foods, like vegetables, meats and poultry, a pressure canner is the only safe method for canning, according to the U.S. Department of Agriculture. A pressure canner costs at least $100, but the investment pays off through grocery savings. The investment also lasts a lifetime, with a canner typically being passed from generation to generation.
Green beans require the high temperatures generated by pressure canning to kill botulism bacteria. It takes roughly three to four hours to prepare and process a batch of vegetables or meat.
Start by preparing the canner according to the manufacturer’s instructions. Second, sterilize jars and prepare lids.
To sterilize jars prior to canning, you can use one of these methods:
- Dishwasher. Run jars through a sterilize cycle on a dishwasher, keeping jars in the dishwasher on “heated dry” until you need them.
- Wash and boil. Wash jars by hand in hot, sudsy water, and then boil for 10 minutes using the canner and jar rack. Keep jars hot until you need them by allowing them to sit in the hot water in the canner, or by setting them on a thick towel and filling each with boiling water.
- Oven. Place jars, open side up, on a cookie sheet in a 200° oven. Slip jars into the oven before you start preparing produce for processing; leave them there until you need them.
To keep jars from cracking, make sure they stay hot until you place them, filled, into the canner. If you filled the jars with boiling water, you can save that hot water by using the jar lifter to up-end jars into your canner.
A common challenge during canning is having enough boiling water on hand. Some cooks invest in an oversize kettle. Others fill a stock pot with water and keep it hot during the process, dipping from it as needed.
Start with fresh vegetables. With green beans, remove ends and snap or cut into the size you desire. Vegetables such as green beans, peas, carrots and corn can be put into jars hot or cold. Potatoes, beets and okra all require a hot-pack method.
With cold pack, stuff uncooked vegetables into jars and cover with boiling water. Hot packing produces a crisper finished product with brighter color. To hot pack green beans, boil beans for five minutes. Strain beans, saving the hot water – you’ll use it.
Place flat metal lids into a pot of hot – not boiling – water. This softens the rubber ring, which helps ensure a solid seal.
Spoon beans into jars, using a wide-mouth funnel if desired. Pack beans tightly to eliminate floating (where beans float freely in liquid after canning). Leave 1 inch headspace between beans and the jar rim.
Pour the reserved hot water over beans; maintain the 1-inch headspace between liquid and jar rim. Use a ruler to measure this space.
Follow recipe directions regarding adding canning salt. With green beans, add 1/2 teaspoon per pint jar; 1 teaspoon per quart jar.
Insert a non-metal spatula between beans and jar sides to remove air bubbles. Tilt jars slightly and press inward on beans to release bubbles. Air bubbles can trap bacteria, so you want to remove as many as possible. Removing air bubbles can lower the liquid level in the jar; add hot water if needed, preserving a 1-inch headspace.
Wipe jar rims with a damp rag. A clean rim ensures a tight seal. Place a flat lid onto each jar. Add screw bands, turning until finger-tight.
Add the rack to the pressure canner and fill the canner with 2 to 3 inches of hot water (follow the manufacturer’s instructions). Turn heat to high. Use a jar lifter to lower jars onto the rack in the pressure canner. Jars shouldn’t touch.
Fit the canner lid in place. Increase heat until steam flows from the vent port on the lid. Allow steam to flow for 10 minutes, and then place the weight over the port. The pressure gauge will slowly begin to rise.
When the pressure reading on the gauge registers the target value (11 pounds for beans), start timing. Process beans in pint jars for 20 minutes, quarts for 25 minutes. Maintain heat to keep pressure at or above the desired value for the entire processing time.
When processing is complete, turn off the heat and remove the canner from the heat source. Allow the canner to depressurize according to the manufacturer’s instructions before opening.
Open the lid away from your face. Use a jar lifter to move jars to a towel or cooling rack. Space between jars facilitates cooling.
After jars cool for 12 to 24 hours, test seals. Gently press down on the center of the lid. If it springs up when you lift your finger, the jar isn’t sealed. Reprocess within 24 hours, or refrigerate and consume within 5 days.
Label jars with date and contents. Store with screw bands off in a cool, dark, dry place. Consume canned vegetables, meats, and poultry within 12 to 24 months for best flavor.