How to Make Homemade Tallow Laundry Soap

Save for later!

This is your complete guide to making natural tallow laundry soap at home. We will teach you how to make an easy, non-toxic DIY laundry detergent!

Traditional soap-making methods are making a comeback among sustainability enthusiasts and homesteaders alike! After testing several batches, I’ve perfected a recipe that works just as well as store-bought detergents for cleaning our clothes.

Whether you’re looking to eliminate chemicals from your home or become more self-sufficient, I’ll walk you through creating a powerful, natural laundry soap that will keep your clothes remarkably clean!

Rendering and Preparing Tallow

You will need rendered tallow for this recipe. If you plan to use your own raw tallow, you will need to clean, grind, and melt the fat before straining and storing it for later use. You can also buy pre-rendered tallow from many local markets or farms.

Check out our full guide on How to Dry Render Tallow if you’re starting from scratch!

This recipe is a 2-step process and does take some planning. You will need to make the base tallow bar soap first and let it cure for 4-6 weeks before making the laundry powder. Check out our tallow soap tutorial for more info on making homemade tallow soap.

Essential Equipment for Soap Making

• Small Crockpot
• Stainless Steel Bowls
• Silicone Spatulas
• Kitchen Scale
• Bowls (stainless or glass)
• Soap Molds
• Soap Cutter
• Baking Pan
• Plastic Wrap
• Immersion Blender
• Infrared Thermometer
• Protective Glasses and Gloves
• Food Processor or grater
• Blender

Ingredients for Laundry Soap

Base Tallow Bar Soap

• 32oz Tallow (rendered)
• 12oz Coconut Oil (virgin, cold-pressed)
• 5oz Castor Oil
• 7.4oz Lye (Sodium Hydroxide)
• 14.81oz Water 

Powdered Laundry Soap

• 8oz Tallow Bar Soap
• 1 Cup Borax
• 1 Cup Washing Soda
• 1/2 Cup Baking Soda
• Essential oils (optional)

Let’s Make Some Tallow Laundry Soap

Making the Base Tallow Soap

1. Organize your workspace and gather supplies, making sure it’s clean and clear of obstructions
2. Weigh tallow, coconut oil, and castor oil
3. Melt tallow and oils together on warm setting in crockpot, until they reach around 120-130°
4. Put on protective gear and weigh lye amount, being sure not to touch any crystals
5. Weigh water into a separate bowl
6. Pour lye crystals into water (snow on a pond) in a well-ventilated area or outside
7. Stir well and leave lye water to dissolve into a clear liquid for about 10-15 minutes
8. Pour heated tallow and oils into another bowl to cool slightly for about 15 minutes
9. Check the temperature of your lye and tallow continuously until they have both reached approx. 100° (it’s okay if lye is cooler than tallow), this can take another 15-20 minutes
10. Once lye and oils have cooled enough, pour lye mixture into oils
11. Keeping the immersion blender submerged, pulse for about 15 seconds, then use stick to stir the mixture, switching between pulsing and stirring a couple times (we don’t want too many air bubbles)
12. Check to see if the mixture is thickening and close to trace* 
13. Repeat previous 2 steps until you reach medium trace
14. Place molds on a baking pan
15. Pour soup batter into molds, tapping baking pan on counter to remove bubbles
16. Cover with plastic wrap for 24-48 hours and if possible, wrap a cloth or towel around the molds to insulate
17. After 24-28 hours, remove from molds and cut bars to desired size
18. Store to cure for 4-6 weeks so that all remaining water evaporates, and bars harden

Creating the Laundry Soap

1. Shred 8oz of cured bar soap in a food processor, or using a grater
2. Measure baking soda, washing soda, and borax
3. In blender pulse together all ingredients until well combined and powdered
4. Store in airtight containers

Notes:

• Always run a soap recipe through a lye calculator — I use SoapCalc.net 
• Wear eye and hand protection, you do not want to be splashed with lye or unsaponified soap
• DO NOT have children nearby while making soap
• Do not use any melt-and-pour soaps (pre-bought soap ingredients often in craft stores) in this process.
• ALWAYS pour lye into water. NEVER pour water into the lye. A hard pocket of undissolved crystals can occur, and you could end up with undissolved lye in your soap, or lye could explode out of your bowl
• Lye water will give off heat and fumes so keep your face away. Be safe!
• *Trace is when the soap mixture has emulsified to the stage of looking like pudding. Let some of the soap drop off the blender or a spatula, and you should be able to see it kind of sitting on top of the rest of the mixture
• Cure soap in a dark, dry area
• Laundry soap recipe makes approx. 6 cups of detergent (24-48 loads, depending on usage)
• Be sure to clean your blender really well after mixing up the laundry powder

Follow Along to Make Tallow Laundry Soap

Making the Base Tallow Soap

Organize your workspace and gather supplies, making sure it’s clean and clear of obstructions. Weigh tallow, coconut oil, and castor oil and melt together on warm setting in crockpot, until they reach around 120-130°.

Put on protective gear and weigh lye amount, being sure not to touch any crystals. Weigh water into a separate bowl.

Pour lye crystals into water (snow on a pond) in a well-ventilated area or outside. Stir well and leave lye water to dissolve into a clear liquid for about 10-15 minutes.

Pour heated tallow and oils into another bowl to cool slightly for about 15 minutes.

Check the temperature of your lye and tallow continuously until they have both reached approx. 100° (it’s okay if lye is cooler than tallow), this can take another 15-20 minutes.

Once lye and oils have cooled enough, pour lye mixture into oils.

Keeping the immersion blender submerged, pulse for about 15 seconds, then use stick to stir the mixture, switching between pulsing and stirring a couple times (we don’t want too many air bubbles).

Check to see if the mixture is thickening and close to trace. Repeat previous 2 steps until you reach medium trace.

Place molds on a baking pan and pour soup batter into molds, tapping baking pan on counter to remove bubbles.

Cover with plastic wrap for 24-48 hours and if possible, wrap a cloth or towel around the molds to insulate.

After 24-28 hours, remove from molds and cut bars to desired size. Store to cure for 4-6 weeks so that all remaining water evaporates, and bars harden.

Creating the Laundry Soap

Shred 8oz of cured bar soap in a food processor, or using a grater.

Measure baking soda, washing soda, and borax.

In blender pulse together all ingredients until well combined and powdered.

Store in airtight containers.

Using Tallow Laundry Soap

We like to use about 2-4 Tbsp of this powdered detergent in a load of laundry. This can vary depending on the machine or preferences. If you have an HE washer, be sure to follow the instructions given by the manufacturer.

Naturally Scent Your Soap

If you like a little scent to your detergent, we recommend putting a few drops of your favorite essential oil in with the tallow laundry soap when doing a load of laundry. You can also mix 5-10 drops of essential oil for each cup of laundry powder and be sure to shake well before storing. Here are some essential oil blends you might enjoy:

• Melaleuca (tea tree)
• Lavender and Peppermint
• Sweet Orange and Lemon
• Cedarwood and Sage
• Lemongrass and Lemon

You’re now ready to create a natural DIY tallow laundry soap that’s sustainable and cares for your clothes! This tallow-based formula uses traditional wisdom with modern efficiency, resulting in a powerful cleaner.

Using a Lye Calculator

You can mix and match many different fats and oils, but it is VERY important to use a lye calculator anytime you make soap. You should always double-check recipes, mine included, using a lye calculator before you make them. Use something like SoapCalc.net to help you calculate how much lye you will need for different ratios of ingredients. You cannot just swap castor oil for coconut oil in a soap recipe because every fat has a different SAP value (how much lye is needed to make a certain fat into soap).

Isn’t Lye Super Dangerous?

Lye by itself is a caustic agent, so yes you do need to be careful. Always wear protective gloves and eyewear and keep it away from children. Fortunately, no lye is left in soaps after the saponification process is completed. Saponification is the chemical process that converts fats into soap by way of sodium hydroxide (lye).

It takes about 24-48 hours for saponification to be completed, which is why we wait a day or two before cutting the bars. Of course, while making the soap you do not want to touch the lye, as it is caustic, or get it on your skin. So be sure to protect yourself during the process!

Why does soap need to cure for 4-6 weeks?

Good things come to those who wait. Technically, cold process soap is safe to use after only a few days. For a better bar of soap though, you’ll want all of the extra water to evaporate so your bar will become harder and long-lasting. We don’t want our soap to become a soft, mushy mess.

FAQS