How To Superfat Hot Process Soap


Do you want to make sure that your homemade soaps come out perfectly each time? The best way to do so is to superfat your soap through the hot process. To help you understand, we’ll tell you exactly how that works!

Discover the secrets‘ Professional soap-makers use to create luscious homemade soaps with this step-by-step guide. You’ll find out what supplies you need and where to buy them, as well as having the instructions written in an easy-to-follow format with lots of pictures for beginners.

Hot processing soap making is a concept that is very similar to cooking. Instead of letting it settle on its own all you do is cook the soap. Now, superfatting is when you add some additional oil to the soap but without changing the amount of oil or lye in the recipe.

Superfatting is an easy but widely miscalculated process that needs equal parts of patience and diligence. So if you’re trying to get this process right, we’re here to help you through it. Dive into this article to find out the best way to superfat your soaps to perfection!

Why Do You Need To Superfat Your Soap?

Superfat is nothing but the extra fat left behind in a soap post-saponification. Most homemade and organic soaps consist of superfat. Here’s why-

  • Safety: Soaps need a certain amount of fat to ensure that no unused lye remains. Soap recipes are primarily based on saponification and pure alkali (KOH or NaOH). So, we aim to always use up all the alkali by adding extra oil or fat. Superfatting requires up to 3% of extra fat to ensure safety.
  • Moisture and Mildness: Soaps aim at cleansing the skin thoroughly. However, they must have moisture and be mild to not make skin dry and irritated. Adding extra oil to soap provides the soap with moisture (emollient moisture).

How to Superfatting hot process soap: The perfect tutorial

We will go through step by step how to superfat your soap. However, before we do, it is best to go through the calculation process first.

Calculating the Superfatting Ingredients

Different oils have varying SAP values, and it takes a particular quantity of sodium hydroxide to convert oils into soaps. So, when curating a superfatting formula, you have to calculate the amount of sodium hydroxide you require for your hot process soap.

In this process, you convert the actual weight of oil into the soap and allow it to blend. Yes, this is equally mathematical as much as it is scientific.

The amount of Sodium Hydroxide = Oil weight x SAP value

  • Olive Oil’s SAP value is 0.134, so, for 500g of olive oil, you need (500g x 0.134) 67g of sodium hydroxide.
  • Coconut Oil’s SAP value is 0.190, so 300g of coconut oil needs (300g x 0.190) 57g of sodium hydroxide.
  • Palm oil’s SAP value is 0.141, so, for 200g of palm oil, you require (200g x 0.141) 28g of sodium hydroxide.
  • Finally, you calculate the total amount, the sum of 67g, 57g, and 28g of sodium hydroxide is 152g.

Ok, now we know how much we need, we can now start making soap and superfat it!

Step 1: Getting The Crockpot Ready

First, heat your crockpot and add the essential oils. Heat the oils to 65° C (150° F) and add the lye solution. (Note: Prepare your lie solution beforehand. Cool it for 20 minutes before adding it to the oils. Use a stainless steel utensil to prepare the lye solution)

The next step is to ensure that the oils are heating properly. Do not let the temperature exceed to beyond 180° F. (Warning: Hot lye and hot oils in a super hot pot can be a mess. It is dangerous and can spill on you and cause burns. Might sound poetic, but we’re serious!)

Step 2: Cooking The Oils

Stir the oils in your crockpot. Please do not leave your solution unattended. This will result in a lumpy, thick solution that will make anything but soap. Once you’re done stirring for a while, check the temperature of the oils.

Etekcity Infrared Thermometer 774 (Not for Human) Temperature Gun Non-Contact Digital Laser Thermometer-58℉~ 716℉ (-50℃ ~ 380℃), Standard Size, Black

I recommend using a thermometer to check the solution’s temperature. If you want to avoid getting your thermometer dirty, you can use an infrared thermometer (which I also recommend for candle making, and it’s perfectly safe!). Checking the temperature is crucial since it indicates when you can add your other ingredients to the oils.

Resume stirring after resting your hand for a few minutes. The trick is to allow the solution to thicken and to get trace, please be aware of a false trace. You can use the 30-second rule to see if it stays or not. (Pro Tip: You can use a hand blender to thicken the solution)

Step 3: Cook and Set

Once you’ve mixed all the oils and the lye solution, you need to cover your crockpot with a thick cling wrap gently. This is so you can retain all the moisture and also prevent the soap solution from becoming dry and sticky.

After the soap is cooked, it will begin to gel and become opaque. Now, turn off the heat and pour the soap solution into molds. This leads us to our actual superfatting process.

Step 4: Completing The Superfatting Process

We earlier established that for 1kg of oil solution, you require 152g of sodium hydroxide to superfat the soap. So, now, add the extra oils to the solution after making the necessary calculations. Here is an overview:

OilWeight (g)SAP ValueEquals To
Olive5000.13467
Coconut3000.19057
Palm2000.14128.2
  Total Value152
  Caustic Soda Total- 15%129
Total Oil Weight1000  
Sodium Hydroxide129  
Water Required (Multiply 33%)373  

The best way to measure ingredients is by using a soap calculator. You can access it on different websites. However, the calculation we provided is quite tried-and-tested for the superfatting process.

Even though some soap makers change the superfat content to as high as 20% or as low as 5%, it is better to stick to an average range. This helps you experiment safely so that you can make future tweaks to the recipe based on personal preferences.

So, to complete the process, you can either add more oil or decrease the amount of sodium hydroxide. (Note: Please don’t randomly pour oils to superfat your hot process soap. This will make your soap too soft and slippery.)

Superfatting when having trace

There are many who are convinced that superfatting during light trace gives you the guarantee that you have more control over the amount of oil and such. The truth is that it doesn’t make any difference at all. In fact, Kevin M. Dunn, aka the ‘Caveman Chemist’ has an excellent book called Scientific Soapmaking. He puts the “superfatting-at-trace” hypothesis through various tests. And within those tests, he clearly states that there is no difference at all when you superfat.

For convenience sake, I would advise adding your oil right in the beginning, this way you’d know the amount, and also there would be no chance for you to “forget” adding it later.

Superfatting: A Mindful Process

The first thing you must be cautious with while superfatting soap is to treat the oils mindfully. Oils get spoilt more easily than actual soap. So, the more you leave unwanted amounts of oil in your soap, the more spoilt it will get.

This spoilage is termed Dreaded Orange Spots or DOS. Small, molecular orange spots on soaps are DOS, and it means that your soap is not fit for use anymore. This is why you should be careful while superfatting your soap.

Once you’ve established a set recipe for preparing hot process soaps, you can experiment with different superfat percentages.

Alternative ways to help your superfatting process further

Here are some tips from various sources I have found:

  • You can add luxurious essentials or luxury butter to your soap solution as a “superfat” component.
  • Superfat ratios vary based on the kind of fat you use for your solution. For instance, if you use coconut oil, you will need a decent amount of superfat. This is to prevent your skin from over-drying from the harsh texture of the oil.
  • Do not add a very large concentration of superfat to your soaps. This will make soaps soft and over-greasy. 
  • You can add extra ingredients like dried flowers, coconut peels, orange shavings, sparkles, and glitter, to your soap after superfatting. It does not hamper the consistency in any way. Instead, it just makes your task simpler.
  • Choose rectangular or square molds for hot process soaps. It makes it easier to add superfat to such molds. Complicated molds with too many designs can make it hard to measure the oils.

Summing Up

Making hot process soaps is not only easy but also a super-fun activity that can spike up your creative instincts. However, superfatting your soap is as important as getting your recipe right.

With this guide, we hope we’ve equipped you with some useful information to superfat your soaps without any trouble. So, what are you waiting for? Follow these simple steps and make your DIY-superfat hot process soap today!

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