They’re quick, they’re cool, and they’re easy…
But the one thing I love most about smoothies??
I can pack a whole lotta nutrition into 1 cup!
Chia, hemp, or flax seeds, grass-fed collagen, antioxidant-rich berries, greens, spirulina, adaptogens like maca… the sky’s the limit!
Why Spinach In Smoothies?
Spinach is one power-packed green veggie that I love adding to smoothies.
It’s rich in fiber, zinc, B vitamins, vitamins A and C, folate, calcium and more! Because it’s high in flavonoids, it protects your body from free radicals, particularly in the colon. Spinach is also brain food! Studies show that it helps maintain brain function, mental clarity, and memory. (Source.)
Unlike kale, which tends to be bitter, spinach has a pretty neutral flavor and doesn’t take away from the sweetness of my smoothie.
The Problem With Spinach In Smoothies
If spinach is so great, why go to the trouble of making spinach smoothie “pucks”?
Well, as nutrient-dense as spinach is, there’s also a problem: oxalic acid/oxalates.
And spinach has lots of ’em.
Oxalates/oxalic acid are to spinach what phytates/phytic acid are to beans, grains, and seeds that haven’t been traditionally prepared through soaking, sprouting, or sourdough. They interfere with mineral absorption by binding to the minerals in the food and preventing absorption.
Calcium is the particular mineral that the body can’t absorb because of oxalates/oxalic acid in raw spinach.
“[A]lthough the calcium in spinach is 115 mg per half cup cooked, because of the interference of oxalic acid, you would have to eat more than 16 cups of raw or more than eight cups of cooked spinach to get the amount of calcium available in one cup of yogurt” (source).
What’s the point in eating calcium-rich spinach if your body can’t absorb the calcium?!
Steamed Spinach Smoothie “Pucks”
Because steaming spinach each and every time you want a smoothie is a pain, these Steamed Spinach Smoothie “Pucks” are super convenient! Plus, 1/3 cup of steamed spinach = approximately 1 full cup of raw spinach!
When you’re ready to make a smoothie or my favorite Hippie Juice, you’ll have pre-steamed spinach that’s low in oxalates and much better for you than raw spinach!
Steamed Spinach Smoothie "Pucks"
Spinach is one power-packed veggie that I love adding to regular and green smoothies. There's just 1 problem: spinach has lots of oxalates. Here's how to lower oxalates and use spinach in smoothies without steaming it every time.
Ingredients
- 36 ounces washed fresh baby spinach
- 1/2 cup pure water
- 1 cookie sheet
- unbleached parchment paper
- 1/3 cup measuring cup
Instructions
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Line cookie sheet with unbleached parchment paper.
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Prepare to steam the spinach. I do not have a special steamer or steaming basket. I simply place a stainless steel colander inside of a larger pot with a bit of boiling water in the bottom. Nothing fancy, but it works!
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Place as much spinach as will fit into your steamer (or pot + colander over boiling water).
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Cover the spinach and steam for 1 minute.
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Remove from the heat.
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Pack the steamed spinach into the measuring cup.
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Flip it over and give it a tap onto the parchment-lined cookie sheet. It should come out the same size and shape as the measuring cup.
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Continue to do this until all the spinach has been used.
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Place the cookie sheet into the freezer.
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Freeze 4 to 6 hours, or until the spinach is in solid "pucks".
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Store in a zip-top bag in the freezer.
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Add 1 smoothie puck to any smoothie for a boost of good-for-you greens with lots of absorbable calcium!
Recipe Notes
- 36 ounces of spinach should yield approximately (6) 1/3 cups after cooking.
Healthy Green Smoothies
Green smoothies are healthy — as long as you’re not adding handfuls of raw greens to them.
Spinach isn’t the only green veggie that’s high in oxalates either. Swiss chard, kale, and beet greens also contain high amounts of oxalic acid. Use this same method for those greens, if you have an abundance that you’d like to add to your smoothies.
Check out these posts for more information about making healthy smoothies:
- Why We Steam Kale (and other leafy greens)
- How To Make A Healthy Smoothie: The Dos and Don’ts
- Healthy Smoothie DOs & DON’Ts Podcast
- 31 Healthy Smoothie Recipes
Don’t Have Time to Make Pre-Steamed Greens?
If you don’t have time to pre-steam greens, you can still get the benefits of dark greens in your smoothie without any of the work by… adding this low-oxalate greens powder (get 15% OFF with coupon DRCOWANSGARDEN) or this fermented kale powder (get 10% OFF with coupon TCS10)!
Do like spinach in smoothies? Have you ever thought about steaming ahead? Would you like to try these Steamed Spinach Smoothie “Pucks”?
...without giving up the foods you love or spending all day in the kitchen!
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Brilliant! Thanks, Lindsey, for this excellent tip. I’ve got spinach on the grocery list. I see green smoothies in my future. Have a blessed weekend!
Sure thing! Enjoy your low-oxalate smoothies!
That is truly Brilliant! Love it!
I’ve been steaming my greens for a wile now but didn’t think to make pucks. I like to add steamed greens to soups, taco filling, just about anything. Thanks for the puck idea. ????
Won’t steaming it affect the taste of the spinach and in turn the smoothie? “Cooked” spinach has such a different flavor than raw spinach. I would love to absorb calcium, but I don’t really want to taste the spinach if you know what I mean.
In my opinion, there is no flavor difference between raw and cooked spinach…and I don’t like cooked spinach. 😉
I was hoping to find something about this recently. Some folks were complaining about heating raw veggie’s for smoothies though because of how heat destroys the vitamins? Is that accurate? Would 1 minute of steaming have much of an affect?
The 1 minute of steaming time dramatically lowers oxalates, but doesn’t cook the spinach to death, which would result in a loss of vitamins.
Do you think that frozen spinach which is blanched would give the same benefit? I’d like not add another task to my already busy kitchen-time!
I understand! If you’re sure your frozen spinach was blanched prior to freezing, then yes, it’s the same. However, the cost is more, especially for organic frozen spinach. Also, these “pucks” are just the right size for adding to smoothies. No breaking apart a brick of spinach just to toss into the blender!
Really great information. I’ve read about oxalates and stopped putting them in my smoothies. I thought about cooking them and that didn’t sound appealing. Thanks for posting the best way to get greens into our smoothies. I’m planning on figuring out how to steam greens in my Instant Pot!
I stopped putting greens in my smoothies for this reason awhile ago. What a great idea to portion out pre-steamed greens like that! I can see greens are going to make a comeback in my smoothies now!
That’s great, Emily! Glad this was helpful!
I have never heard of this! So I guess we shouldn’t be eating raw spinach salads either? I have always heard that spinach was one of the best raw greens to eat. This is the first I’ve heard it’s not.
Ideally, no. A raw spinach salad a couple of times a month probably isn’t going to hurt you (unless you know oxalates or kidney stones are an issue — in which case you should avoid raw spinach completely!). But there are people who make green smoothies on a daily basis with raw spinach, and that’s a problem. If a daily green smoothie is part of your lifestyle, I highly recommend making these “pucks” for best results.
What about other greens? Kale and collareds?
Yes, kale is also high in oxalates and should be steamed prior to consumption. I’ve read mixed reviews on the oxalate content in collards, however I have never heard of adding collards to a smoothie before either. 🙂
When im vlc or ketoadapting I put collards or turnip greens in my smoothies. Along with other greens too–I rotate them. I add stevia as theres no fruit or dairy, just homemade coconut milk, salt, eggs, coconut oil. You must learn to like these, yes lol
My coconut milk is just grinding the shreds with water in the blender for 3 min (no straining, I like coconut) then adding greens and grinding for 3 min more. Now I wont be grinding the greens as theyll be the pucks.
Hi, What about dandelion greens?
Dandelion greens are not high oxalate but they are medium oxalate. So cook them also.
Cool. This method may be a bit more work, but it will also keep the spinach from going “off” in the refrigerator if I don’t use it fast enough!
Exactly! It’s a great way to keep expensive organic spinach from going to waste!
Wouldn’t using frozen spinach from the grocery store work just as well? It is blanched before it’s frozen.
If you know it’s blanched, yes, it would be the same. However, the cost may be significantly more, especially for organic frozen spinach. Also, making these pre-portioned “pucks” saves you from having to break chunks of spinach from a frozen brick. 🙂
I’m thinking we don’t really know how the frozen spinach is prepped. It may be cooked to death before it’s packaged for the freezer section.
Typically green foods turn sort of grey-ish or brown-ish when they’re overcooked (think canned green beans or canned spinach). Frozen spinach, in my experience, is quite bright green. However, we don’t know if it is blanched or steamed prior to freezing. Further, even if it is blanched or steamed, frozen organic spinach is not cheap, and therefore, steaming and freezing yourself is a much more economical option.
I think i ll try this with the other greens i want in my shakes too, kale, chard, etc. Maybe chiffonade them first so they quick cook. They take awhile to cook. Baby greens r quite good in shakes too. Do these contain as much oxalates as the mature leaves?
Thank you for the tips! I started on my health journey and within 6 months had my first kidney stone. I had added a lot of greens to my diet, especially in smoothies. I am wondering if that was the cause of my kidney stone. I will try to steam my greens first from now on. 🙂
It’s very possible that your kidney stone was the result of too many oxalates from raw greens, Kim. Hope this works better for you!
Thanks for the info. I knew we shouldn’t eat a lot of oxylates, but didn’t know why!
We juice carrots with spinach on a daily basis with a Champion juicer. Does juicing make any difference rather than blending in a smoothie? I guess we could juice the steamed spinach or kale. But it is one more step I’d like not to do! Thanks for your information and suggestions.
I personally think eating the whole food is better than the juice. Not only is it more economical (you’d have to juice A LOT of spinach!), you’re getting the fiber as well as the enzymes and benefits of the juice.
I think the question was about the oxalate levels in juiced spinach as compared with whole fresh leaves. I don’t know for sure, but I would assume the oxalic acid would be the same either way?
Raw spinach in any form in high in oxalic acid. Plus, spinach isn’t efficient for juicing. It takes an enormous amount of spinach to produce a very small amount of juice.
Great idea! But please no plastic bags for storage. They last for hundred of years, and, among other problems, they break down into small pieces and are eaten by birds and sea life.
I use the same bag over and over, rather than pulling out a new bag every time I make my smoothie pucks. I agree that plastic bags are a bad choice for the environment and the planet, however sometimes they are the most convenient thing. I just choose to wash and re-use whenever possible and recycle when I can’t re-use.
Is cooking spinach by sautéing or adding it to a boiling liquid the same as steaming it in terms of oxalate reduction?
Any cooking method will reduce oxalates, however a quick steaming is the most effective method to reduce oxalates while maintaining high levels of vitamins and minerals.
It appears boiling and draining the liquid is needed to get rid of oxalates. I would save spinach, kale (curly, not dinosaur) or beet greens for occasional use raw or steamed (or occasional baked for kale) The low oxalate greens can be used steamed for most ppl. Boil the other, hardy, medium oxalate greens.
Interesting!! So it sound like spinach salad is a no then too? 🙁
Ok, so I was wondering what dehydrating does as far as oxalates is concerned. I dehydrate mine and add that to my smoothies. When you dehydrate, you use heat, so does that reduce the oxalate?
This is exactly what my doctor suggested since I told her about my digestive issues with green smoothies. Not the puck part, but steaming the greens prior. Such a great idea, thank you.
I was all excited about this idea and shared it with my friend who is a GAPS practitioner. She responded with the article (link below) and said that you can’t really get rid of oxalates in spinach and it doesn’t necessarily lower it in other greens either. So if someone is following a low oxalate diet they will still not be able to do the greens-in-smoothies 🙁
http://oxvox.com/cooking-food-does-not-lower-oxalate-levels/
If you boil the greens and drain and rinse them, you will remove 90% of the oxalates.
I sometimes purée the spinach and freeze in cubes. Is there any reason the pucks are better?
Nope, cubes are fine, too! 🙂
Is there any scientific evidence that steaming will not reduce the oxalate content… thanks
Or just buy frozen spinach from your favorite grocery store. It’s blanched before freezing so it will have oxalates removed/reduced just like this process, and pathogens killed.
Lemon juice greatly reduces oxalates too. I simply add lemon juice along with raw spinach (or any other raw greens, even if they’re in a powdered form) to smoothies. But I like your method of steaming and freezing in cups too. Thanks for sharing! 🙂
Never heard acid reduces oxalates.
Thank you many times over for information on oxalate avoiding. It is challenging to do. I am curious, though, about the steaming of greens & the lowering of oxalate content. I have read that the amount of reduction is really very small when greens are steamed & there is great potential to also reduce the amount of other nutrients that we don’t want to lose. Can you comment on this please? Thank you very much
P.S. I also live in a northern MN wilderness location in our “happy place.”
If you want daily greens, use low oxalate ones raw or steamed or medium oxalate ones boiled and drained. Stay away from high oxalate ones.
Unless you can tolerate them raw always. Most ppl get nauseated after a week of daily greens not cooked.
Thank you for this reply Helene. However, it does not address my question. I am asking what you think of the information from other sources that say that steaming or boiling really do not reduce oxalate content much at all & that both have a greater potential to also cause a reduction in other water soluble nutrients, which would negate the benefit of the tiny bit of oxalate reduction from them. And Alice, I too have never heard/read that lemon juice reduces oxalate content. Curious about the source of this information & what kind of testing has been done to validate that happening. Thanks both of you for your assistance in helping me understand these thoughts better.
Been researching about oxalates and all the info I have seen says first that spinach is one of the veggies with the HIGHEST oxalates…especially if you COOK them. It is higher in oxalates COOKED than raw! Check it out under foods with highest oxalates.
Just to inform.
What about with kale; how much steamed kale would you use? Would 1 cup of raw kale also equal 1/3 cup steamed kale?
Thank you!
I did not realize this about Spinach. Thank you for the information
Is it ok to use regular spinach? I know the recipe specifies baby spinach – is there a specific reason why?
Is there a difference in nutrition if I steam the pucks and freeze them, or steam them and dehydrate them to grind up into a powder? Is it just a matter of preference? The frozen pucks seem easier, but the dehydrated powder is shelf stable.
Just found your site. Suggest using muffin tins to freeze the pucks in because it is much easier and faster. After filling with steamed greens simply sit the tin in some warm water in the sink for a few seconds, pop them out, and then into a freezer bag for storage.
To clarify- the spinach is sitting ABOVE the water in the strainer as one steams it?