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By Stacy Benjamin – Pressure canning kale and other greens leave your freezer space available for other things that aren’t as well-suited for canning. If you’re like me, you fill up your garden beds to maximum capacity and then have trouble keeping up with all of the summer bounties! In particular, I find keeping up with the prolific summer greens to be a challenge. An easy way to preserve greens for winter when you’re short on time is to blanch and then freeze them, but with a little more effort, they can be preserved by steam pressure canning.   

If you’ve canned using a boiling water canner (also called the water bath method) then you already have a working knowledge of the important safety concepts involved with food preservation that will also be used with a steam-pressure canner (pressure canning). If canning is entirely new to you, this article will give you a crash course, and I highly recommend reading a canning guide from a reputable source that delves deeper into the proper techniques required for safe canning.  

Pressure canning is used for low-acid foods, including most vegetables that cannot be safely canned using a water bath canner. Leafy green vegetables must be canned using pressure canning. You can use a pressure canner on the stovetop, or if it’s a hot day and you don’t feel like heating up your kitchen, you can set up an outdoor canning station (which is my preference) by using portable electric burners and other heat sources for canning. Be sure to gather everything you’ll need before you start canning to make the canning process a smooth one.

Canning Equipment

• Pressure canner
• Canning jars
• New canning lids and rings
• Large pot for blanching
• Large bowel of ice water
• Colander
• Boiling water for topping up jars
• Long tongs
• Tool for removing air bubbles
• Jar Lifter
• Towels

Preparing the Greens:

When pressure canning kale and other greens, select mature greens in good condition from the garden. My favorite type of leafy green to can is kale. You can also can other greens such as chard and collards. Pick them right before canning and wash thoroughly to remove any dirt hiding within the crinkly leaves. Remove the stems and tough center rib, along with any discolored, diseased, or insect-damaged spots. I also like to rip or chop large leaves into coarse pieces. Blanch the greens in a large pot containing a few inches of boiling water for three to five minutes until the leaves are well wilted. Blanching stops enzymes from degrading the quality during storage, so this is an important step. You can use a steamer basket to hold the greens, or alternately, I just drop them in the pot of boiling water and use long tongs to remove them. Immerse the wilted greens in a large bowl of ice water to stop the cooking process. After the greens have cooled, place them in a large colander to drain. Continue blanching and cooling the remaining greens until they are all ready for canning. You will be surprised how much the greens cook down after blanching. When pressure canning kale, I always pick a really big bunch of greens so that I can fill enough jars to make the canning process worth the time it takes.  

Preparing the Canning Jars:

Pack the cooled greens into pint canning jars. Fill to approximately 1 inch from the top of the jar, and don’t pack too tightly. Add 1/4 teaspoon salt to each jar if desired for taste. Cover with fresh boiling water leaving 1-inch headspace. Use a narrow spatula or another non-metallic tool to remove air bubbles from the jars by slowly turning each jar and moving the spatula up and down. Wipe the rim of the jars to remove any water or debris that would prevent the jars from sealing. Place the lid on, and tighten the ring securely on the jar.  

Pressure Canning:

Place a jar rack on the bottom of the canner so that the jars are not sitting directly on the bottom. Add hot water until it is a few inches up the side of the canner. Place the jars into the canner, leaving space between the jars. If you have a large canner, you may be able to fit a second row of jars on top. Be sure to use another jar rack before adding the second row of jars. Tighten the lid of the canner to get a secure lock. Depending upon the type of canner you have, it will have either a weighted pressure gauge or a dial pressure gauge on top. The instructions for maintaining the proper steam pressure will vary a bit depending on the style of gauge you have, so read the instruction manual to understand how the pressure gauge works before you start the canning process.  

If you are canning on a stove, heat the canner over high heat. If you are using an outdoor propane burner, you’ll want to keep the flame fairly low. As the canner is heating, you will need to watch the pressure gauge on the canner to see when it has reached the correct pressure.

The pressure you will need to maintain will vary based on the type of canner you have and your altitude. Once the canner reaches the correct pressure, you will begin timing. Refer to the instruction manual to understand when the proper pressure is reached and when to begin timing. You’ll need to maintain a constant pressure for 70 minutes for pint jars, or 90 minutes for quart jars. After the processing time has passed, remove the canner from the burner and allow the canner to depressurize to zero before opening. After depressurizing, carefully open the canner, remove the jars and allow them to cool. As the jars cool you should hear a high-pitched ‘ping’ sound indicating that the vacuum seal has pulled the lid down into place. Let the jars stand at room temperature for 12 hours before testing the seals.  

Storing Canned Jars:

After the jars have cooled, test the lids to make sure all of the jars have sealed. A securely sealed jar will have a little indent in the middle of the lid and will not push down when you press your finger on the lid. Any jars that have not sealed should be refrigerated and eaten in a few days. Jars with a good seal can be stored in your pantry for enjoying all winter long. The texture of canned greens will be soft. My favorite ways to enjoy them are adding them to hearty winter soups or simply warming them and seasoning them to taste for an easy greens side dish.   

Do you have experience in pressure canning kale? We would love to hear how it turned out!

Originally published in the July/August 2021 issue of Countryside & Small Stock Journal and regularly vetted for accuracy.