Getting the Proportions Right for Tallow-Based Homemade Soap

Reader Contribution by Sarah Hart Morgan
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Photo by Sarah Hart Morgan

I love this time of year. The garden is reaching its summer end and you have to start getting creative on how you can use up your surplus so nothing goes to waste. A friend of my husband’s recently butchered a few head of cattle and asked if I wanted some of the beef fat for soap-making. There was no way I was going to pass up the free fat, and after two days of rendering, it was time to get to work on the soap.

My apothecary cabinet was getting pretty full and I needed to make room for new infusions, so I decided this would be a “clean out the fridge” type of soap. I had a bumper crop of tomatoes this summer, too. After canning every red tomato from my garden, I still had a ton of green tomatoes on the vines that I knew more than likely weren’t going to turn this season. I picked all that I could before the frost got hold of them, made salsa verde, and gave even more away to friends. I had made a very successful bar of soap years ago using my heirloom tomatoes and decided to try a batch using the juice of the green tomatoes as the liquid in this batch of soap.

Juicing the Tomatoes

I used green roma tomatoes for this formula but any green tomato will work. You don’t want seeds or any added tomato pulp in your soap so after blending the tomatoes in my blender with a little bit of water to get the blender going, I ran the liquid through a fine mesh sieve to remove the seeds and pulp. I added this to my compost pile (the chickens loved it!) so nothing went to waste.

Cleaning Out the Apothecary

Photo by Unsplash/
Aurélia Dubois

I’m not sure about you, but I have an abundance of infused oils in my apothecary cabinet this time of year. And to be honest, they were probably past their prime. The oils hadn’t gone rancid by any means, but they were at the point where they were at risk of needing to be discarded if I didn’t do something with them soon. After the growing season, I have fresh plants and herbs that will need to be infused, so it was time to get out with the old and in with the new.

A big batch of soap is just the right way to use the oils up so nothing goes to waste. In this batch I used: lavender-infused olive oil, wild rose-infused olive oil, juniper berry-infused olive oil, and red clover-infused olive oil.

The Formula

I like to work and share my formulas using percentages. It’s easier to scale the formula to fit your own mold and by converting to weight, you work in precise measurements. Be sure to run this formula through a soap calculator like this one using the size of your own mold to get the proper lye/liquid measurements. I like to use a digital kitchen scale when measuring everything.

Photo by Sarah Hart Morgan

Clean-Out-the-Apothecary Soap Proportions

Super Fat 7%

Beef tallow:  60%

Olive oil: 25%

Unrefined shea butter: 10%

Castor oil: 5%

Notes:

I like to add 1.5% beeswax of my total weight of fats and oils. This doesn’t get factored into the total weight of fats and oils; rather, I treat it as an additive, though it gets added to the fats during the melting stage.

My green tomato juice was used in place of the water, and I typically use around a 10% water discount when I soap.

I don’t use any fragrance oils in my soap as a personal preference, and I no longer use essential oils either as the scent doesn’t last and it seems like money wasted. Instead, I like to use infused oils to gain the skin-loving benefits of the plants I use.

This bar of soap ended up with a very naturally clean, pleasant scent. It is a very hard bar of soap that should have a nice lather, and was easy to cut after 24 hours. I personally like to let my soap cure for 6 weeks before use.

If you try this formula, I’d love to know what kinds of infused olive oil you used and what, if any, liquid substitutes you used. This type of soap is one of my favorites to make, similar to cooking when you just throw a little bit of this and a little of that and see what happens.

Photo by Sarah Hart Morgan

Sarah Hart Morgan is a designer, photographer and author of Forrest + Thyme Apothecary: simple skin care formulas you can make uniquely your own. She lives in the Shenandoah Valley, where she works with foraged plants in her skincare and apothecary products, camera-less photography, using plants as a developing agent in film photography, and creating natural inks for painting. Connect with Sarah on her website, Instagram, Facebook and Pinterest. Read all of her MOTHER EARTH NEWS posts here.


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