The Secret to the Absolutely Best Soap Recipe

Your perfect soap recipe probably doesn’t exist. Yet.

Tired of testing endless recipes from randos on the web, never finding the perfect one? Well, I’m going to let you in on the secret.

After years of formulating soap recipes for soap companies (including two of my own), I can create a soap recipe with a specific list of characteristics without even touching my supplies. That skill came from learning the basic building blocks of a soap recipe and how to combine them.

  

What's your perfect soap recipe wish list?

What are your must-haves when it comes to making the perfect bar soap?

• The best soap recipe produces a bar with a luscious creamy abundant lather.
• It creates a rock hard bar of soap that is long-lasting (but not too long-lasting!)
• A perfect soap formula cleanses without being overly drying and has just the right amount of skin-nourishing oils and additives.
• And of course, the ideal soap recipe wouldn't cost more than $1.50 per bar to produce.

Sound like music to your ears, rockstar?

Well, maybe.

The thing about the best soap recipe?

The perfect soap recipe is as unique as you are. It's the holy grail of soapmaking.

Therefore, the features I like in my soap are probably different from what you like (and different than what your customers like!) I love creamy tight bubbles. When I drop a bar of soap on my floor, I love when it's so hard that it's completely unscathed.

Also, I like to lather a bar of soap in my hands (while you might like to use a loofah.) And I have semi-soft water on tap (while you might have extremely hard water.) These factors change how a bar of soap can perform.

So, that means the perfect soap formula for me is not necessarily the perfect soap recipe for you. And more importantly, what your customers feel is the best soap recipe might be wildly different from either. (Honestly, they probably aren't as picky and keen to minute changes as we are, as soapmakers!)

First, list up what’s important to you in a bar of soap. (And, if you are selling, remember, what’s important to you is what your customer wants!) 

Takeaway: The perfect soap recipe is different for everyone. Decide what matters most to you and your customers.

Perfecting an existing soap recipe

If you are starting with an existing recipe that you already like, just a few adjustments may turn it into a soap formula you love. (But, if you are starting from scratch, things get a bit more complicated. More on that below.)

If you are looking to increase the size of the bubbles or the amount of lather in your soap recipe, try:

• Increasing the percentage of oils that contribute to bubbly lather, like coconut oil, palm kernel oil, and babassu oil
• Decreasing the superfat of the total oils, as too many free oils can cut down on lather
• Using lather increasing additives like sodium citrate, sodium lactate, sugar, or rosin
• Replacing the water with a lather booster that contains sugars, like beer or wine

If you are looking to stabilize or sustain lather in your soap recipe, try:

• Using castor oil at 5% to 10% of your recipe. (Be forewarned, using more than 15% castor oil tends to make the bar sticky, tacky, and rubbery.)
• Adding or increasing oils that support lather, like almond oil, lard, tallow, cocoa butter, palm oil, shea butter, or sunflower oil
• Decreasing oils that do not contribute a lot to lather (or hinder it), like olive oil

If you are looking to increase conditioning in a soap recipe, try:

• Replacing the water with alternative liquids, like goats milk (or other milk), yogurt, or aloe vera juice
• Increasing the superfat of the total oils to condition the skin
• Adding or increasing nourishing oils, like apricot kernel oil, avocado oil, olive oil, rice bran oil, or sunflower oil
• Adding "luxury oils" at 5% to 10%, like argan oil, evening primrose oil, flaxseed oil, hemp seed oil, jojoba oil, meadowfoam oil, pumpkin seed oil, or wheatgerm oil

If you are looking to increase bar hardness in a soap recipe, try:

• Increasing your hard to soft oil ratio, by using a higher percentage of hard oils (oils that are solid at room temperature)
• Adding stearic acid at 0.5% to 1% of the total soap formula
• Including beeswax at 1% to 5% of the total soap recipe
• Adding sodium lactate at 1% to 3% of the total soap formula

Want a soap recipe to start off with?

Check out my soap making tutorials to see if a recipe strikes your fancy, like this recipe featuring avocado or this one using coconut milk. 

Formulate your best bar soap recipe from scratch

To formulate effectively from scratch, you must first learn about the properties of the oils you have available and their fatty acid profiles. Next, with that base knowledge, you can start putting a recipe together that ticks all your boxes for a perfect soap recipe. (Additives are the very last thing to consider when formulating a soap recipe.)

Formulating based on soap oil properties

If you want to give it a go formulating your own soap recipe, try this basic soap formula builder:

• 60% Hard Oils
  • 25% to 45% Lathering Hard Oils
  • 15% to 30% Conditioning Hard Oils
• 40% Soft Oils
  • 20% to 30% Nourishing Soft Oils
  • 5% to 10% Luxury Soft Oils
  • 5% to 10% Castor Oil

Hard oils are solid or semi-solid at room temperature.

Soft oils are liquid at room temperature.

Lathering hard oils include coconut oil, palm kernel oil, babassu oil, and murumuru butter.

On the other hand, conditioning hard oils are oils and butters such as palm oil, cocoa butter, lard, tallow, kokum butter, illipe butter, sal butter, mango butter, and shea butter.

Some examples of nourishing soft oils in a soap recipe are high oleic sunflower oil, high oleic safflower oil, olive oil, canola oil, almond oil, apricot kernel oil, and avocado oil.

Luxury soft oils include oils like evening primrose oil, walnut oil, wheat germ oil, hemp oil, rosehip oil, and pumpkin seed oil.

Lastly, castor oil stands in a league of its own. There are no comparable oils due to its unique fatty acid profile! Castor oil is well worth its inclusion in a small percentage in a soap recipe to sustain beautiful lather.

Remember, these are all rough guidelines to help you find YOUR perfect soap recipe.

Formulating your soap recipe based on fatty acids

Soap formulation software often makes use of fatty acid profiles behind the scenes. However, fatty acids are rarely explained. For instance, SoapCalc uses fatty acid profiles to determine their soap formulation quality numbers.

An oil’s fatty acid profile is a tally of what percent of each type of fatty acid that oil contains. A soap formula’s fatty acid profile is the tally of the combined oils in that recipe. Each type of fatty acid brings different characteristics to the party. So, look at your wish list for your perfect soap recipe and match your fatty acid profile to that.

(We actually surveyed the community to find out other makers’ favorite fatty acid profiles. You can see those and our own fatty acid preferences for body soap in the post: Most Popular Fatty Acid Profiles in Soapmaking.)

Oil properties are directly related to the fatty acids an oil contains. For example, coconut oil is high in lauric acid. That's where coconut oil gets it's lather boosting ability. And it is solid at room temperature because lauric acid is a saturated fatty acid.

But, familiarizing yourself with fatty acid profiles, rather than only the properties of individual oils is a smart move. Doing so allows you to:

• Substitute oils in an existing soap recipe
• Control the cost to make your soap by selecting less expensive oils
• Pick oils that will have label appeal for your target market.

Fatty acid characteristics

The major fatty acids found in soap oils are:

• Lauric acid - a saturated fatty acid that contributes hardness, cleansing, and big fluffy lather
• Myristic acid - a saturated fatty acid that contributes hardness, cleansing, and fluffy lather
• Palmitic acid - a saturated fatty acid that contributes hardness and stable creamy lather
• Stearic acid - saturated fatty acid that contributes hardness and stable lather in soapmaking
• Oleic acid - is an unsaturated fatty acid that contributes to the conditioning/moisturizing abilities of a soap
• Linoleic acid - an unsaturated fatty acid that contributes to the conditioning/moisturizing levels, as well as silkiness of the lather
• Linolenic acid - an unsaturated fatty acid that contributes to the conditioning/moisturizing levels, and is typically present in very low amount in soap formulas
• Ricinoleic acid - an unsaturated fatty acid that contributes to the conditioning/moisturizing levels, and the stability of lather

(Capric, caprylic and palmitoleic acids are generally at such low quantities that they don’t contribute to soap qualities in a noticeable way. However those fatty acids are similar to lauric and palmitic but more conditioning.)

The home stretch...

Once you have a recipe that looks good on paper, you are 90% of the way to your perfect soap. And you’ve narrowed down what you need so you don’t waste money on extraneous supplies. Try out your recipe, changing one variable at a time, until you are happy!

Do your first trial run without additives. All too often, we see folks trying to fix a bad recipe with additives when they’d be better off going back to the drawing board. And, it's helpful to know the base color of your soap and if you have issues controlling trace before you add color and scent to the mix.

If you are totally stuck on trying to perfect your recipe: I can help you get there with my exclusive video class over at The Nova Studio. In plain English, I'll teach you the chemistry behind soapmaking, the significance of fatty acids, the ratios to formulate different kinds of soap, and how to troubleshoot. Therefore, you'll never rely on anyone else's recipes ever again.

Do you have any other tips or tricks to formulating the best soap recipe you want to share? Leave a comment and let me know!