Superfatting Homemade Soap: Extra Hydrating Oil for a Luscious Bar

Have you ever wondered how to make a superfatted soap? Superfatting your handmade soap is the answer! Superfats are oils that have been heated and then cooled. This process creates excess oil in your mix, which will ensure a more hydrating bar of soap. In this article, we’ll go over some tips on how to superfat homemade soap.

The best oils for superfatting soap are Olive oil if using a liquid oil, or if using a hard oil butter look no further than Shea Butter. Each oil has to be added to the exact correct measurement for saponification and adjusted based on what percentage of superfatting you aim to achieve.

Whether you have discovered this article by searching for superfatting, or more likely, are looking for the best oils to use for superfatting, it might be the first time you have come across the process. read on to find out more.

Too much oil in your soap, or your soap has gone soft?

One of the reasons you might be here is that you have found that your soap has not cured and hardened as you expected it to and you are now wondering why that is and how you can remedy the problem.

In fact what might have happened, as is the most likely cause is that you have used too much oil, and the excess is free-floating in your soap, preventing it from hardening as much as you would desire.

What you have done in essence, is superfatted your soap, by providing more oil than can be saponified by the lye, a process that is often undertaken to make a more luxurious bar of soap, but in this instance, it has been overdone, too much oil has been left over which will both leave your bar soft and maybe mushy, which in turn will also mean the lather in your sap will also be killed by the oil.

So let’s remedy that issue right away with a formula that can be used to provide you with just the right amount of oil to superfat your soap correctly, and allow you to experiment with different levels to find the perfect finish you are looking for.

What is superfatting soap?

Superfatting soap is using more oil than is required to create the perfect saponification with the Lye in your cold process mix to ensure that excess oil is leftover adding a more luxurious finish to your craft-made soap bar but without preventing the lather we love.

This may be the first time you have come across superfatting in soap making

Superfatting Precentage

The level of superfatting soap can be expressed in a percentage figure to match your recipe or use as information on your recipe if you are selling differing levels of superfat in hydrating bars of soap, from which your customer can choose the level of luxury they are after.

The most popular superfatting soap level is 5% – This adds a good amount of leftover oil for hydration but will do less damage to the lather providing, in my opinion, the most luxurious bar of soap you can produce.

  • Plenty of oil left to treat your skin
  • The bar will cure and harden very well
  • The lather will not be affected adding to the luxury

So this all looks great, you now know what superfatting is, the benefits, and selling points but how do you now make your soap to the superfat percentage you want?

If you are using Olive oil on your soap, and you want to achieve that 5% superfat level, use the following formula

First, you need to know how much Lye is required to turn your oil into soap, using Olive Oil in this example, which is 1.34oz Lye to 10oz Olive Oil

The value in the table are per 1oz of Oil

OilPer 1ozPer 10 oz
Almond Oil0.13671.367
Coconut Oil Refined 760.1911.91
Hempseed Oil0.13591.359
Olive Oil0.1341.34
Rapeseed Oil0.13281.328
Shea Butter0.12961.296
Sunflower Oil0.13581.358
Walnut Oil0.13491.349
Oil to Lye Saponification Chart

Click here for a Chart of OIl to Lye Saponification values which you will need depending on the oils you are using in your soap

Now all you have to do make 5% is take the amount of Lye and multiply it by 0.95

The 0.95 is arrived at by taking 0.05 (5%) away from 1 – Simple see, So…

1.34 x 0.95 = 1.27 oz of Lye

If you want 10% Superfat, the formula is 1.34 x 0.90 = 1.20 of Lye and so on

How much Superfat can I have in soap?

I wouldn’t recommend going above 15% superfatting soap, things can get a bit tricky then and you are moving into the realms of a softer bar of soap which will have less lather and can also affect the delivery of your fragrances and consistency of any coloring

My advice here is to begin with 5% and experiment around those levels depending on just how happy you are with the results you achieve each time.

Important: – We are dealing with very minimal changes in recipes here, so it is super important to be absolutely exact with your measurements so you can see and compare the effects.

Haphazard measuring may leave you confused to the end result and levels of superfatting, so I recommend using a very accurate set of kitchen scales for making sure your recipe is exactly as you want to achieve the superfatting results you desire. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to, or

Recommended Kitchen Scales

There are a couple of choices of kitchen scales that will work just fine depending on how focused you become on superfatting your homemade soap.

For the beginner

If you want to experiment with superfatting soap, then this digital Kitchen Scale will be just fine. It allows you to set a Tare weight, super important when dealing with exact measurements, covers common measurement settings, and 1g graduation. It’s a good-looking scale and will be ideal for a beginner soap maker.

Taking it Up a Level for exact measurements

For the mad scientist and soap maker who is looking to create the most precise measurement of ingredients for soap making and superfatting to extreme accuracy, this lab scale will measure to a 0.01g increment, giving you even more precision over your superfatting percentages.

Troubleshooting Superfatting

You should have all the info you need to go make your super luxurious superfatted soap now, if you are having problems with either of the two bullet points below, it will be because there is too much leftover fat, meaning your superfatted percentages are too high.

Also bear in mind that different fats will require different levels of Lye and you can check the complete chart here


You now have the information to take your homemade soap making to the next level and start creating superfatted soaps which will be more luxurious have additional hydration properties and even start experiment with various types of oils to see which perform best for you.

The most fun part about making soap at home is that you are in complete control of the soap you make and the finish.

You can now bring your imagination into the game and use this information to really create unique soaps with your own mark on them.

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