How to Make Eggshell Calcium Powder

My daughter MK made me some homemade toothpaste a couple of years ago that I really liked. It was very similar to this recipe but she added calcium powder to it. She bought calcium supplements and emptied the contents of the gelatin capsules into her toothpaste concoction. I have wanted to make her toothpaste recipe for a while but have avoided buying calcium powder. Like most supplements, it comes in either a big plastic bottle or a glass bottle with a big plastic top.

Then I remembered something MK had told me a couple of years ago: You can make calcium powder from eggshells. How could I have forgotten about this?

The eggs

First things first. I don’t buy eggs from just anywhere. I get mine from farmers I know. I live in an intentional community, which bought a farm a few years ago. It has been keeping chickens for a couple of years now and I have a weekly egg subscription. These well-treated, pastured hens roam free and eat an organic diet. Unafraid, they run up to humans visiting the farm. The farmers themselves are all vegetarians and we do not eat these chickens.

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A vendor at the farmer’s market takes my cartons to reuse

This is not an Rx

Chicken eggshell powder contains lots of calcium. According this this study, “It may be used as a Ca source in human nutrition.” You can read the entire article here. According to the studies the article cites, 1 gram of eggshell calcium contains roughly 400 mg of calcium. The National Institutes of Health (NIH) recommends adults consume 1,000 mg of calcium per day.

I’m not a doctor but my sister is and when I told her about my homemade calcium powder, she said some studies link calcium supplements to heart disease. Read more about the calcium supplement controversy here on the Harvard Medical School blog. Michelle, like many doctors, suggested I get my calcium—and other nutrients—from, well, food.

I’m not prescribing eggshell calcium to anyone. I’m merely explaining what I’m up to. Personally, I would eat this stuff in place of a calcium supplement, if I took one. I am using this eggshell calcium for toothpaste however (by the way I’m not a dentist either…). I’ll add a couple of tablespoons to my usual toothpaste recipe, which you can find here. I’ll also add more coconut oil since with the addition of this powder, the toothpaste will be quite thick.


Eggshell Calcium Powder

Ingredients

  • 12 eggshells
  • water

Directions

1. Save cracked eggshells in the refrigerator until you have enough. I used about a dozen for this post, which I accumulated in about a week.

egg-shells

2. Boil the shells gently in water for 10 minutes to kill germs.

shells-boiling

3. Scoop off any white foam that forms.

white-foam

4. Drain the eggshells until dry. I drained mine on a cooling rack for an hour or so. Overnight would be better as these would require less time in the oven, they would be so bone-dry.

draining-shells

5. Spread shells out on a cookie sheet and bake in the oven at 200 degrees for about 30 minutes to dry them out completely.

baked-shells
Dried egg shells after 30 minutes in the oven

6. Crush eggshells in a coffee grinder, food processor or mortar and pestle. I quickly first crushed mine in my hand.

crushed-shells

I then put these crushed shells in my blender. I do not recommend this. My blender, a bit of a dud, spewed fine powder all over the place. I think a coffee mill or spice grinder (I have neither) would have worked better.

blender-mess
Ugh, I have to clean this up after I post this blog…

So my boyfriend Chandra suggested I switch to a mortar and pestle.

pregrind
Gritty eggshells in my mortar

You can see the eggshells are quite coarse above. I think that’s okay if you just want to ingest them for calcium. You can mix them into a drink if you like. But for toothpaste, I wanted a fine powder that would be gentle on my teeth. I managed to render powder, although it took a while with such a small mortar and pestle.

ground-powder
Fine eggshell powder

Chandra is a potter and so has lots of practice grinding up glazes in a mortar and pestle. Here’s a clip of him using mine for the shells.

8 Comment

  1. Hi, hope you’re well, would you not save energy (yours as well) by skipping the boiling and drying phase by using the sojourn in the oven to kill all the germs ?
    I’d imagine you get a slightly abrasive powder that way, a great plaque remover.
    I have clay and all and intentions to make some toothpaste for the longest time and I hope I manage to take the time to do that soon.
    By the way made your delicious fermented salsa earlier this summer and I loved it.
    Take care M-A

    1. That should work. The oven would kill any germs at 200F. I would need to wash/soak the shells first to get off any egg white residue. I’ll try it next time. Thanks for the idea. The clay I have works really well with my sensitive teeth. I hope you find some time to make yours and that you like it. Glad you liked the salsa. Isn’t it good?! ~Anne Marie

  2. Can you share your toothpaste recipe using THIS calcium powder please??

    1. I will have to write another post on that Madeline. I’ll do that in the next couple of weeks.

  3. Hey Anne-Marie, I wanted to let you know that I have a very good blender, and it still makes just as much mess! I put a damp tea towel over the lid when I blend, and wait for it to settle before pouring into a jar, but it still wafts into the air (and my lungs) and leaves a thick film of dust everywhere. My pestle and mortar has a wooden stick bit (I can never remember which bit is which!) so it doesn’t work great. And you can’t buy the sticks on their own…

    1. Hi Lindsay. Well maybe I shouldn’t be so down on my blender then 😉 What I would really like is a coffee grinder. My boyfriend has a second-hand coffee grinder that he reserves for grinding up cinnamon sticks only. He ground some up for me on the weekend. The cinnamon turned out very finely ground and powdery, no cinnamon in the lungs! My mortar and pestle has also seen better days :/ But I need only a little bit of this stuff for my tooth powder. ~ Anne Marie

  4. […] for toothpowder. Clever, I thought, but I didn’t take action on this until I came across Zero Waste Chef’s post on making the same and then considered my lack of bulk calcium carbonate powder […]

  5. This is a wonderful idea – thank you! I have been looking for a ZW method of upcycling the eggshells we use in our house, and it looks like this is going to be it! 🙂

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