Kale is a super sturdy veggie and freezes beautifully. It freezes so beautifully that people who grow kale swear the best, sweetest kale is the kale that’s been kissed by frost. And while there may have been a time that you might have picked up a huge bag of kale and let it linger a little too long, those times are past…if you know how to freeze kale the right way! It’s a game-changer and there’s no need to ever waste a single leaf.
Now first, a disclaimer. If you are just interested in having some kale to drop in your smoothies and aren’t necessarily concerned about the quality (since it’s blended anyway) just chop up some kale and toss in in portions in your freezer for short term. No need to read further, no discussion necessary. Mic drop. Boom. See ya later and thanks for stopping by! 🙂
About How to Freeze Kale Correctly:
But if you want to preserve your kale at its peak, this post is for you. In a couple of super-simple steps you’ll have kale that’s just as beautiful coming out of the freezer as it was going in. It will be great for salads, sides and to use in recipes. Any time you use a little kale in something, you’re going to up your nutritional game. So why not have it around to use in more ways than just in your morning smoothie?
When preserving, it never hurts to have a little knowledge to make sure you’re keeping your product and your family in good shape. So we’ll talk a little about food safety, quality and nutrition so you’re going to be well-armed and avoid any pitfalls along the way.
You can just jump ahead to the printable if you want but if you at least scan through the information you’ll know the whys and that’s knowledge you can use anytime you want to freeze just about any vegetable.
Food Safety & Freezing:
Leafy green vegetables have a history of many recalls and food notices. You want to be aware of what possible contaminants there might be and how to handle whatever product you’re using. Spoilage organisms can be present in your kale while it’s growing and introduced along its travels to get to you. And of course, you can introduce them yourself once in your home. (See cleanliness, below.)
Your freeze should be set at 0 degrees or below for best safety and food preservation. It can be a difficult temperature to maintain with a refrigerator/freezer combination, especially if the door is opened often; keep a closer eye on those types of freezers and the food in them.
Freezing won’t destroy bacteria or organisms like Clostridium botulinum or E coli or any other; for the most part, it just holds them in a kind of suspended animation. What goes in the freezer comes out, the bad with the good, and once your kale warms up as it thaws, so do all bacteria and other organisms, to do what they do best: multiply.
There are two big danger zones to be aware of when those nasties can multiply quickly:
- When freezing does not take place rapidly.
- When thawing.
Thawing is one of the most worrisome. While it might seem as if there’s little danger of thawing vegetables outside of the refrigerator, especially if the package feels cold, the outside surfaces can warm faster and bacteria can begin to reproduce there. Factor in the moist environment and before you know it there can be a veritable invisible stew of bacteria laced throughout your kale. Thaw in the refrigerator or quickly and safely thaw when using in a recipe.
First of all make sure your kale is sound, especially if you’ve bought it in a package. While loose-leaf kale may sustain some damage in places, usually at the stems if wrapped in wire or rubber band (it’s a good idea to remove those from any vegetable as soon as you get it home whether you’re freezing or not) and stems can be trimmed off, bagged kale has dangers of its own.
If your bag of kale has liquid or any slime or smells bad (beyond the normal bitter smell of kale) discard it. It’s really not enough to take out portions that still look good and use them. The high moisture content in those bags will ensure any bacteria will have multiplied and spread throughout the kale.
Make sure your work surfaces, any cutting boards, knives, and your hands are well washed and clean. Counters are often not as clean as they seem. There’s really no need to go through heroics and lots of products to clean your counters but do wash with a clean rag (sponges are one of the worst offenders as far as carrying bacteria and it’s a health code violation to use them in restaurants) and soapy water and thoroughly dry.
Wash your kale in a colander, not directly in the sink, by thoroughly rinsing under a strong steady stream. This applies to all leafy greens; simply swishing them in water and draining them is not enough. Ideally, any vegetable you clean should never touch any surface of your sink; sinks are ideal breeding grounds for bacteria of all sorts.
If your kale is homegrown or from the farmers market there is a greater chance of passengers. Aphids and other infestations can be hidden among the leaves. Generally, soaking in a solution of vinegar (about 3 tablespoons to a gallon of water) will take care of them. The kale floats while most pests will sink to the bottom. Thoroughly clean each leaf. Remove the kale and rinse thoroughly under running water.
Enzymatic Action and Quality:
All vegetables and many other plants (and animal products) have proteins present called enzymes. Their job is to ripen and mature your food. Even after your vegetable is picked, those enzymes work heroically, turning green tomatoes into red, turning avocados from hard to soft, and so on. And yet still they continue after food has ripened – until the food has unattractive textural and color changes.
Unfortunately, enzymes are still at work at freezer temperatures. That is why kale (and all kinds of vegetables, fruit, and other food) that isn’t treated, with enough time, will not be so attractive when it comes out of the freezer. It’s still safe and fine for things like smoothies but may not be so great for eating or in recipes.
Two things are commonly used when freezing to stop enzymatic action. The first is citric acid (some use Vitamin C), a common food additive, and the other is blanching. Blanching can be done by steaming, boiling, or in the microwave and has the added benefit of destroying some of the micro-organisms that might be present on your kale. It also shrinks the kale which is great if freezer space is a premium.
Blanching is quickly cooking in boiling water, steam, or microwave and stopping that steaming process by plunging into cold (under 60 degree F.) or ice-cold water. Blanching is essential to preserve the quality of kale or any vegetable frozen for more than a brief period of time in the freezer. For kale, the recommended blanching process is the Boiling Water Method.
- If using cold water, plunge the blanched vegetable into a container of cold water and keep running cold water into the container until the kale is cool.
- If using ice water, the rule of thumb is a pound of ice per pound of vegetable. The disadvantage to ice water other than the logistics of needing ice is both the kale and the ice float making it difficult to remove the kale without ice once the kale is cool.
When done correctly, blanching:
- Destroys some microorganisms on the surface of food ensuring a safer product.
- Stops enzymatic action and preserves color and nutrients.
- Shrinks the size of the kale; it will take up less room. There’s an added advantage that it’s easier to eat the more kale.
When done incorrectly:
- If not blanched enough, the enzymatic action can speed up; under blanching is worse than not blanching at all.
- If blanched too much, the kale may be overcooked and slimy. There may be a loss of structure, color, and nutrients.
Once the kale is blanched it should be drained, preferably spun, and or rolled in a clean kitchen towel to remove most of the moisture.
Other Advantages of Blanching Kale:
In addition to preserving kale, blanching may have other beneficial aspects.
While boiling or steaming kale for six to eight minutes will reduce most of the soluble (and about 1/3 of the total) amount of oxalic acid, the simple blanching to freeze will remove some of it. (See What to Know About Kale for more information, under the nutrition and downside portions of that text.)
While I eat kale both raw and cooked, oxalic acid can be a problem. It can bind with minerals and prevent the body from absorbing those precious nutrients. It’s also blamed for kidney stones, especially those suspectable. Traditional Cooking School has a page with more information, Why We Steam Kale.
Preserving the Texture of Frozen Kale in The Freezer:
All freezing causes some textural changes. The simple act of freezing will rupture some cell walls and freezing for too long can cause further damage through changes in humidity. Freeze for long enough and vegetables can dry out while being covered in frost. Freeze even longer and you risk freezer burn.
Luckily, kale is one vegetable that in spite of being a leafy green (most don’t freeze well) freezes beautifully after blanching. While many people purchase kale and go through heroics to use it fresh in salads, softening, salting, massaging, when kale is frozen the freezer does the work for you.
- Drain your kale well after blanching, spin if you can, and if necessary, spread over a clean towel and roll it up to remove excess moisture.
- Wrap well (heavy Ziploc type freezer bags work well) and freeze quickly to minimize cell damage.
- Make sure as much surface area as possible is in contact with a frozen surface. Placing the bags on a metal sheet tray that has been in your freezer for 30 minutes is ideal.
- When frozen, the individual bags may be placed in a larger bag or container to protect them if desired. Make sure to label, preferably before filling.
There are pots called Blanchers that come with a wire mesh basket and cover, and if you regularly prepare items for the freezer it can be nice to have. If you have a setup like a large pot with a pasta strainer, it will work well. So will any large metal strainer with enough room to hold the kate that will fit into a large pot with a lid.
At the very least you can do like I do. Just boil the kale directly in the pot and empty the pot, kale, and all into a large strainer set over another large pot in the sink.
If using this method, which is slower and can potentially lengthen the time the kale spends in the hot water, even as you pour the kale into the strainer have the water running as cold as possible. As soon as the kale is transferred pick up the strainer, still running the cold water over it and empty the pot underneath, replace the strainer in the pot in the sink and continue running the cold water over and into it.Print
Freeze Kale the Right Way
- Total Time: 20 - 30 minutes
- Yield: equivalent 1 pound 1x
- Category: Preserving
This is a preferred method for many home cooks.
- 1 gallon of water
- 1 pound of kale (prepared as desired, see note)
Bring water up to a vigorous boil and lower kale into water. Add lid. The water should begin boiling again within 1 minute (if not, there is too much kale for the amount of water.) Time for two minutes as soon as the water returns to a boil.
Immediately plunge into cold or ice water when time is up, strain to remove excess water, spin if you can or spread the kale out on a clean kitchen towel and roll it up.
Wrap well (Ziploc type bags are great) and freeze quickly.
Keeps well for 10 to 12 months in the freezer. Longer freezing is not a safety issue but may affect quality.
Note: When preparing kale, chop into desired size, remaining aware that the kale will shrink when blanched. The heavy stems may be removed and used or not. If not, save and add to smoothies and if using, finely chop and blanch with the rest of the kale.
Keywords: Freezes Well, Kale, Preserving