How To Make Soap From Animal Fat + Properties of Different Fats

Whether you raise your own cows or pigs, hunt, or just want to make use of an animal part that’s often thrown away, using animal fat to make soap is frugal and sustainable. While it may sound tricky, learning how to make soap from animal fat is a traditional practice that involves using just distilled water, lye, and rendered fat. Beef tallow or pig lard are two common types of fats.

Lard or tallow soaps are hard, long lasting, and moisturizing.

We’ll look at the various properties of common animal fats, and show you how to render, and make a simple cold process soap recipe using basic ingredients and beef tallow. Plus, we’ll also share a recipe for a blended lard and vegetable oil soap.

Let’s get started!

Why use animal fat to make soap?

Using animal drippings or fat and turning it into soap is something homesteaders have been doing for generations.

The practical art of soap making actually goes back further—at least thousands of years. In 600 B.C.E., the ancient Phoenicians made soap from burnt ashes and goat tallow. The Celts also produced soap made of animal fat and plant ashes; they called it saipo which is where the modern term soap derives from.¹

Now, learning how to make soap from animal fat isn’t for everyone. If you are vegan, or vegetarian, or just plain opposed to using animal products, then I understand you won’t want to use animal fat.

However, this back-to-basics approach to making soap using what you have available is a time-tested and reliable way to create good soap. Call it zero-waste living, or self-sustainability if you like.

Rather than throwing away an animal part, you can convert it to good use and make something natural and useful for yourself and family.

While different animal fats have unique properties, most produce hard bars of soap with a creamy lather.

What’s the difference between lard and tallow?

While people often use these terms interchangeably, lard refers to pig fat, while tallow comes from a variety of grazing animals. Most commonly you’ll find beef tallow, but there’s also deer tallow, goat tallow, bear tallow, and sheep tallow.

Both lard and tallow make fine bars of soap.

Does soap made from animal fat smell?

No, properly rendered animal fat will not produce smelly soap. This is one of the most common concerns that people have. Rest assured that you won’t smell like a slab of bacon, or a rib-eye steak after lathering with an animal fat soap!

A properly made lard soap or tallow soap should have a mild smell. If the idea of animal fat soap still turns you off, you can always add some fragrance oils or essential oils to mask the smell.

Benefits of making soap using animal fat

The benefits of making your own soap using animal fat are many.

• Inexpensive: Many vegetable oils, including coconut oil, olive oil, or shea butter, can quickly add up. Using animal fat from your own animals is the cheapest soap making oil you can use. Even if you buy your own rendered lard, it’s still cost-effective if you’re watching your pennies.
• Low waste living: I love the idea of not wasting any part of an animal—it shows respect to the animal and to the environment.
• Moisturizing (but not greasy): Lard or tallow soap bars are mild and moisturizing, without leaving the skin feeling greasy. They’re great for those with sensitive skin or dry skin.
• Makes good, long-lasting bars: Some vegetable oils used in soap making have a shorter shelf life as some oils oxidize quickly. Not so with lard or tallow soaps. You’ll find they produce hard and long-lasting bars of soap with similar properties of palm oil.

Where to find lard or tallow

Some grocery stores sell rendered fat in tubs or boxes. You can also try asking a local butcher for leftover fat or trimmings (you’ll have to render it of course yourself, which we’ll cover below).

You’ll also find rendered fat online at most soap suppliers, and on Amazon.

Of course, if you have your own animals at home (or have a farmer friend), you’ll have access to free lard or tallow!

Types of animal fat and their properties in soap

Most animal fats are fine to use in a one-fat homemade soap recipe (or single-oil soap). But the fat from chicken and geese are too soft to use on their own.

Here’s a look at the various properties of lard and types of tallow in soap. Notice that some are harder than others (a higher number shows more hardness).

Also note that every animal fat has a different SAP value, or saponification number. This means that some types of fat will require more (or less) lye to convert it into soap. The values are different depending on if you’re using sodium hydroxide lye (NaOH), or potassium hydroxide lye (KOH).

It’s always a good idea to run your numbers through a lye calculator first such as Soap Calc. (That’s where I obtained the following numbers.) http://www.soapcalc.net/calc/soapcalcwp.asp

Table: Animal Fat Properties in Soap

	Pig Lard	Beef Tallow	Bear Tallow	Deer Tallow	Goat Tallow	Sheep Tallow
Hardness	42	58	12	45	69	51
Cleansing	1	8	2	1	16	14
Conditioning	52	40	79	48	31	31
Bubbly lather	1	8	2	1	16	14
Creamy lather	41	50	10	44	53	37
NaOH SAP	0.141	0.143	0.139	0.138	0.137	0.138
KOH SAP	0.198	0.2	0.1946	0.193	0.192	0.194

As you can see, goat tallow is the “hardest” when used as a single oil, followed by beef tallow, sheep tallow, and pig lard. Bear tallow is the softest of animal fats listed above.

An overview on rendering fat

An important part of learning how to make soap from animal fat involves learning to render fat. Rendered fat is simply “clean” melted fat that has been strained of any impurities.²

If you’ve collected fat from your own animals or a butcher, set aside an afternoon to render fat for soap.

You’ll need:

• A large pot
• Wooden spoon
• Cheesecloth, sieve, or slotted spoon to remove cracklings
• Several glass mason jars or heat-safe containers to store rendered lard
• Cutting board and knife
• Water (for 10 pounds of fat, use 4 cups of water; for 1 pound of fat use slightly less than 1/2 cup of water)

1. Cut into small pieces. Gather trimmings and cut into small chunks of fat. This helps speed things up.
2. Heat on low. Place pieces of fat into a large pot on the stove. Add water (slightly less than 1/2 cup of water per pound of fat) and heat on low.
3. Stir occasionally. Depending on how large your batch is, it can take one or two hours to completely melt the fat. Resist the temptation to turn up the heat—this may burn it.
4. Look for cracklings. Cracklings are the small brown pieces that form on the bottom. Once your fat is finished rendering, you’ll see cracklings appear at the bottom.
5. Strain and store. Carefully strain the hot rendered lard or tallow by pouring into a sieve, or using a cheesecloth. It’s important to use heat-proof containers such as mason jars. Continue straining until all cracklings are removed. Allow the rendered fat to cool before storing.

Your rendered fat should have no (or little) smell. At room temperature, it’ll look white and creamy. Store in the refrigerator until you’re ready to make soap from scratch.

Read up on lye safety first

If you’ve never made soap from scratch before, please read up on basic soap safety before you begin.

The type of lye you’ll need to use is pure sodium hydroxide lye crystals (NOT the stuff with added chemicals!).

Lye is a caustic chemical that can harm skin and eyes. It creates an exothermic reaction when mixed with water—it can reach temperatures of 200 degrees Fahrenheit (93 degrees Celsius).

When mixed with water, lye releases fumes, which is why you’ll want to work in a well-ventilated area. Wearing protective equipment is also a must. Grab a pair of safety goggles, gloves, and wear a long-sleeved shirt.

Use heat-safe and non-reactive utensils and equipment such as stainless steel and silicon, and some types of plastic. Lye reacts strongly with aluminum.

Check out an in-depth article about basic soap making supplies.

Tips on heating fat

Before you get started, it’s good to note that there are different ideal temperatures to heat various types of animal fat. Avoid cranking up the heat as this may burn and darken the color of the finished soap.

Type of Fat	Temperature (Fahrenheit/Celsius)
Vegetable oil	110–115 °F (43–46 °C)
Bear	115 °F (46 °C)
Beef	130 °F (54 °C)
Deer	130 °F (54 °C)
Pork	120 °F (49 °C)
Sheep	130 °F (54 °C)

How to make soap from animal fat: step by step

The following recipe uses the cold process soap making process.

Since we already have an article about making lard soap, this one uses beef tallow.

Pure beef tallow soap recipe

Beef tallow as a single oil makes for a white bar of soap that’s hard and long lasting. It won’t create a bubbly lather, but it makes a mild, creamy lather with plenty of skin loving moisturizing properties.

This recipe uses 5 percent superfat.

Yield: Roughly 1½ pounds of soap, or roughly 4 bars of soap

Supplies:

• Digital kitchen scale
• Thermometer (digital, infrared, or candy thermometer)
• Immersion blender (stick blender)
• Stainless steel saucepan for melting the lard
• Heat-safe jug for the lye solution
• Rubber spatula for stirring and scraping
• Loaf mold or individual silicone molds
• Wax paper or piece of cardboard to cover the soap mold
• Old towels to insulate the soap mold
• Safety gear (goggles and gloves)

Ingredients:

Lye solution:

• 6.08 ounces distilled water
• 2.17 ounces sodium hydroxide lye

Fat:

• 16 ounces rendered beef tallow

Fragrances:

• Optional: 0.5 ounces of your choice of essential oil (lavender essential oil is a popular scent)

1. Prepare the lye mixture. Put your safety gear on—it’s about to get hot in here! Measure the distilled water and add to heat-safe jug. Measure the sodium hydroxide and slowly add to water (NOT the other way around). Allow the lye mixture to cool.
2. Measure and heat tallow in a saucepan. Warm the fat over low heat in a stainless steel saucepan until melted, stirring occasionally.
3. Bring to trace. Once the lye mixture has cooled and is of similar temperature to the combined oils, carefully add the lye to the oils. A good temperature is somewhere around 110 degrees Fahrenheit (43 degrees Celsius). Use an immersion blender (stick blender) to combine the soap batter until it thickens and turns opaque (reaches trace).
4. Add essential oil. Once your soap batter has reached trace, add your essential oil and stir to combine. This step is optional. You can leave your bar unscented if you prefer.
5. Pour into mold. Pour the soap batter into a prepared mold. Cover with wax paper or a piece of cardboard. Wrap some old towels to insulate the soap.
6. Set, cut, and cure. Allow the soap batter to cool and harden (at least 24 hours). If soap has hardened, unmold and cut into bars. If bars are too soft, allow it to set for several more days. Let the soap bars cure for 3 to 4 weeks in a well-ventilated room. You’ll get a longer lasting bar this way.

Lard, olive oil, and coconut oil recipe

A blend of vegetable oils combined with lard strikes the balance between conditioning and cleansing properties. Coconut oil is a highly effective cleanser and creates fluffy lather. A splash of castor oil brings the bubbly lather most people love in a soap bar.

The following cold process recipe is from Alicia Grosso’s The Everything Soapmaking Book.

Yield: Roughly 1½ pounds of soap, or roughly 4 bars of soap

Ingredients:

Lye solution:

• 5 ounces distilled water (172.36 grams)
• 2.3 ounces sodium hydroxide lye

Hard oils/fats:

• 5 ounces lard
• 5 ounces coconut oil

Soft oils:

• 6 ounces olive oil
• 0.5 ounces castor oil

Directions: Follow the same cold process steps as the pure tallow recipe above. In Step 2, melt the lard and coconut oil first before combining with the soft oils.

New to making soap? 🧼❓

👉We have a fantastic overview on the whole soapmaking process here: read our Timeless Guide To Soapmaking.

If you would like to see our soapmaking posts organized by topic type, see our Soapmaking Collection.

References

1. Britannica, Soap, Soap, https://www.britannica.com/science/soap. Accessed January 2022.
2. Emery, Carla (2012). The Encyclopedia of Country Living, 40th Anniversary Edition. Sasquatch Books. pp. 635–637. ISBN-13: 978-1-57061-840-6.
3. Grosso, Alicia (2013). The Everything Soapmaking Book, 3rd Edition. Adams Media. pp. 90. ISBN 13: 978-1-4405-5013-3.

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