Kale is a hearty, healthy green, great during the cooler months as other warm weather greens, such as spinach or arugula fade out for the year. It’s also a brassica (like broccoli), which you can enjoy year long with this guide on how to blanch kale for freezing.
Kale is a common green but not as heavily studied as a functional food. Yet, a cup of kale has 2 grams of protein, 1.5 grams fiber, 90 mg calcium (~10% DV), good source of iron, excellent source of potassium and a day’s worth of Vitamin A and Vitamin K.
Kale is very nutrient dense and in addition to its on label nutrition, kale also contains several phytonutrients like lutein and zeaxanthin as well as prebiotics like hemicellulose.
These nutrients help diversify, and therefore improve the health of your gut microbiome.
So let’s get into just how to blanch kale, freeze it for future use and other questions related such as, what happens if I don’t blanch my kale?
Do I need to blanch kale for freezing?
Yes. For the best quality, and food safety, blanching greens is a necessary step. If you’re ready to just blanch your greens then skip to the step-by-step guide on how to blanch kale for freezing. Otherwise, I’m going to get sciency for a second.
We always hear that blanching halts enzymatic activity in plants, thus preventing food quality degradation. But what the heck is an enzyme?
An enzyme is a protein that helps make a reaction occur in a living thing, AKA a catalyst. An example in humans is protease, this is an enzyme that helps break down protein that we eat. So enzymes are not just inert things, they’ll continue to react, albeit much more slowly in the freezer.
Blanching helps to halt these reactions because when greens are put into boiling water their enzymatic activity speeds up, due to the rising heat and are then deactivated after a duration under boiling water.
Step-by-Step Guide to Blanching Kale
Let’s blanch kale!
1. Prepare your space:
– Fresh kale (organic, if possible)
– Large pot, colander, large bowl filled with ice water, tongs and/or wooden spoon
– freezer bags, containers or vacuum sealer
– Sheet pan to individually freeze, or muffin pan to freeze in roughly 1 cup portions
– a few clean kitchen towels, or paper towels for drying
– timer
2. Clean and Prepare the Kale:
– Rinse the kale thoroughly under cold water to remove dirt, pesticide residues, bugs and the like. I like to use my (sanitized) sink for large amounts of kale, for smaller amounts a salad spinner works well.
– Remove tough stems if desired, the stems contain fewer phytonutrients than leaves, but are still edible.
-Rip the leaves into bite-sized pieces for easier use after freezing.
3. Blanch the Kale:
– Boil a large pot of water.
– Add the kale and blanch for 2 minutes, ensuring the leaves turn a vibrant green (indicating nutrient retention).
– Immediately transfer the kale to an ice bath to stop the cooking process.
– If you have more than one batch it is safest to change out the water to avoid cross contamination and ensure a cold bath for each set of greens.
4. Drain and Dry the Kale:
– Remove kale from the ice water after 2-3 minutes.
– Thoroughly drain and pat dry to prevent freezer burn.
How to Freeze Blanched Kale
1. Portioning for Convenience:
I suggest freezing kale in meal-sized portions for ease of use. My favorite way to do this is by stuffing blanched kale into muffin tins. Freeze in muffin tins, then package as little “cups”. These work great for smoothies!
Another way is to freeze in single layers on a baking sheet first before transferring to bags to prevent clumping.
For the best quality frozen kale I freeze in vacuum bags if possible to limit oxygen exposure, since air is one of the ways food degrades both in nutrition and quality.
Be sure to label with the date to ensure optimal freshness (kale can be stored for 8-12 months).
How many minutes to blanch kale?
How to Use Frozen Kale for Gut Health
-Add to Smoothies: my favorite! Conveniently boost fiber and antioxidants in smoothies with frozen kale.
– Toss into Soups and Stews: frozen kale retains its texture well in cooked dishes, adding fiber and gut-friendly nutrients.
– Sneak into Sauces: like pesto, you can swap some basil for greens, or make an herb dressing.
Stir-Fries: kale can be incorporated into a variety of stir fry dishes to enhance gut health and jazz up the color of any dish!
How do you dry kale after blanching?
After blanching kale, drain it thoroughly using a colander or salad spinner. To remove excess moisture, gently pat the kale dry with a clean dish towel or paper towels. You can also use wire racks to allow the kale to dry further.
Ensuring the kale is completely dry before freezing helps prevent freezer burn and improves texture upon thawing.
How long will kale last in the freezer?
Properly blanched and vacuum sealed kale should last eight to twelve months in a deep freezer. Don’t forget to label and date your kale!
What happens if you freeze kale without blanching?
While blanching is often recommended before freezing vegetables, there is some research suggesting it may not always be necessary, depending on the type of vegetable and the intended use.
Blanching is generally used to stop enzymatic activity, which can lead to color, flavor, and texture degradation over time, even in frozen vegetables. However, some vegetables like onions, peppers, tomatoes, and certain root vegetables can be frozen without blanching, especially if their texture changes won’t impact the final dish. For example, onions can be frozen raw because their flavor and texture remain largely unaffected.
For leafy greens like kale, blanching may seem like an extra step, but in fact it’s important for food safety since the heat will kill any pathogens, in addition to the main intent, which is to halt enzyme activity.
I’ve cut corners in the past and eaten frozen greens that weren’t blanched; their texture is tough and chewy and the taste is much more bitter.
The exception to this rule is if you don’t have a ton of kale and plan to use it within a short amount of time, say a few weeks. And, when the texture of the thawed kale won’t impact your final dish, like in a smoothie.
Does freezing kale destroy nutrients?
While freezing can lead to a small loss of water-soluble vitamins like vitamin C, and some B vitamins, most nutrients are retained, making frozen kale still a highly nutritious option for use in smoothies, soups, and stews. Studies show that freezing is one of the best preservation methods to maintain vegetables’ nutrition.
However, it’s important to remember that this loss would happen naturally, overtime in the freezer if the kale isn’t blanched. Blanching kale briefly in boiling water deactivates enzymes that can cause nutrient degradation over time, helping to retain the vegetable’s nutritional value.
Other foods preservation methods to preserve kale
In addition to freezing, other methods to preserve kale include dehydrating, fermenting, and canning.
Dehydrating kale involves drying the leaves until crisp, making it a perfect snack or powder for smoothies. Fermenting kale enhances its probiotic content, supporting gut health, while canning (usually in soups or stews) provides a longer shelf life.
Each method has its own benefits, but all help retain kale’s nutrients and allow for year-round consumption, with variety in textures and flavors!
So now you know how to blanch kale for freezing, and why it’s necessary! I hope your garden gives you an abundance of kale that you get to enjoy all winter long 🙂
Step-by-Step Guide to Blanching & Freezing Kale
Equipment
- – Large pot, colander, large bowl filled with ice water, tongs and/or wooden spoon
- – freezer bags, containers or vacuum sealer , for freezing
- – Sheet pan to individually freeze, or muffin pan to freeze in roughly 1 cup portions , for freezing in portions
- – a few clean kitchen towels, or paper towels for drying , for drying
- – timer
Ingredients
- 1 lb Kale, about 5 large stalks
- 1 gallon water, boiling, per 1 pound of greens
- 1 gallon water, ice bath
- Ice
Instructions
- Begin by adding 1 gallon of water to a large pot. Optional to place a straining pot within the larger pot, or simply pull out leaves with tongs.
Clean and Prepare the Kale:
- Rinse the kale thoroughly under cold water to remove dirt, pesticide residues, bugs and the like. I like to use my (sanitized) sink for large amounts of kale, for smaller amounts a salad spinner works well.
- Remove tough stems if desired, you can do this with your hands simply scraping against the "grain", or with a tool built for this use.
- Rip the leaves into bite-sized pieces.
Blanch the Kale:
- To the boiling pot, add 1 pound of kale and blanch for 2 minutes, ensuring the leaves turn a vibrant green (indicating nutrient retention).
- Immediately transfer the kale to an ice bath for an additional 2 minutes.
Drain & Dry the Kale:
- Remove kale from the ice water bath and place on a clean, dry kitchen towel. Alternatively you can use paper towel or a cooling rack.
- Thoroughly drain and pat dry to prevent freezer burn.
- Once the greens are dry place place on a cookie sheet and freeze individually, or a favorite method of mine is putting ~ 1 cup of greens in muffin tins and freeze in portions.
- Once your greens are frozen in the portions you desire, vacuum seal for best quality. Or zipper lock bag, minimizing excess air.
- Label & date, freeze for 8-12 months.
Notes
- Amount of water for boiling, and ice will vary based on the amount of kale you have to freeze; these amounts work for one pound increments.