Can you cure cold process soap in the fridge?

Cold process soap is a great way to make your natural soaps at home, but it can take weeks for the soap to cure.

Some use their fridge to cut the curing time, but does this method really work? Or are you doomed to end up with a failed batch of soap? 

Curing soap in the fridge might be helpful, but don’t expect it to have any remarkable change in the result. Some soaps may cure faster or slower – it all depends on the recipe. Some recipes may benefit while others will cure even slower. It’s highly recommended to cure your soap at room temperature if you’d like it to be ready as soon as possible. 

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Lately, I’ve been hearing more and more people talking about curing cold process soap in the fridge. Some say it works, while others claim that using one will slow down your soaps’ cure time by up to two weeks! But are these claims valid? Let’s find out together…

I’m not going to lie – when you first hear this idea for accelerating CP Soap with a fridge, my mind immediately went, “Why?” And after some research on whether or not there really was an effect here at all, well, let me say the answer to this burning question might surprise you. 

Can you cure soap in the fridge?

Yes, it’s possible to cure soap in the fridge. However, please note that the curing time will not vary at all – they’ll still need to be kept in that enclosed environment until the cure period is over. 

Still, many soap artisans choose to cure their soap in the fridge because it’s especially helpful if you live in an area with high humidity. As you know, fridges are dehydrators, so it will help you dry your soap out while keeping them as cool as possible, as if you were storing it in another area.

Then, some advise not to cure soap in the fridge as it may lengthen the curing time. Furthermore, it is destined to be in an environment with high humidity, so drying them out wouldn’t really change that much. They also argue that doing this can be counterproductive as the fridge will help you “dry” the soap out too fast. If that happens, the soap will end up “warping.”

So, although it is possible, you have to think thoroughly about what the best option for you at the moment is. Some people don’t even experience results after curing their soap in the fridge.

Can you put cold process soap in the fridge to harden?

So, curing soap in the fridge can be a good thing (or not), but what about leaving cold process soap in the fridge to happen? Unfortunately, the answer to this question is not much different from the previous one is.

For starters, if you put warm soap in the fridge, it’ll end up causing condensation. Therefore, it may lead to sweating problems once the soap is ready to use. However, putting soap in the fridge AFTER it has cooled down can help you take it out of the mold with ease – that if you’ve used silicone or a plastic mold.

Putting cold process soap in the fridge probably won’t help harden it, but it will actually prevent the gel phase. Still, please note that with soap, you never know. It’s all about trial and error and experimenting with recipes. But above all, it’s about being patient. Some things may work when the right conditions are reunited, while others may not have an effect at all. 

How do you harden cold process soap?

When it comes to making cold-process soap, it’s all about patience, as the hardening process takes several days. 

But, the time it takes for a batch of cold process soap to harden can vary depending on multiple factors. On average, the soap will last between 2-3 days, but too many conditions affect this process and make the waiting time longer than what you might expect. For instance:

  • If you use more soft oils (olive, sweet almond), the bars will become softer than you expect.
  • On the other hand, if you use hard oils in the recipe (coconut, cocoa butter), the soap will harden quicker.

Suppose you’ve made soap from olive oil at 100%. That means it can take up to two weeks to harden. However, if you choose to make 60% hard oils soap, you will likely be able to unmold it after one day or two.

One way to speed up the hardening process of your cold processed soap is by taking these few steps:

  1. Use a balanced level of superfat.

More factors have to do with how fast cold process soap hardens. One of them is the superfat, which is the oil that remains unaffected by the sodium hydroxide lye, and therefore, does not saponify.

Soaps can be made from anywhere between 1-7% superfat. The higher the percentage, the softer and less harsh your final product will turn out, but this comes at a price – if you are using seven or more percent of oils in an otherwise all-suds recipe, it may lead to soft bars after waiting for them to harden.

My advice is to use about 5% superfat in your cold process soap as it adds more balance to the soap bar and feels gentler on your skin.

  1. Use fewer colorants.

Most of us add some “extra” elements to our recipes from time to time, such as fragrance oils and colorants. These agents are also responsible for making your soap soft, especially if you’ve added too much of it.

If you include too much-dispersed colorant in your recipe, you’ll most likely end up with too soft soap – and the same can happen if you end up adding more oil to the mix for whatever reason. Suppose you’ve included about 7% superfat to your soap recipe as well as lots of dispersed color. That will end up giving you a very soft soap bar.

The usual rate for dispersed colorants is one teaspoon per one tablespoon lightweight liquid oil. However, if you’d still like to add more colorant to your cold process soap, you can use less oil in your dispersion.

  1. Add less fragrance oil.

As mentioned above, adding too much fragrance oil to your cold process soap can make it turn out softer than it should. That’s where Fragrance Calculators can help you – this way, you can make sure that you’re utilizing the right amount of fragrance oil for your recipe.

  1. Don’t use too much liquid.

Adding too much water to your recipe can be quite prejudicial to the soap. Most recipes use about 22% distilled water, although the total amount can fluctuate based on what you’re making. Using less water can also be helpful to unmold your soap faster.

If you add too many extra liquids, your soap will not harden as it should, and you will end up with a soft soap batch.

How long does it take for cold process soap to cure?

It takes from four to six weeks for cold process soap to cure. Curing the soap for longer periods helps it gain firmness and makes it long-lasting. It’s also worth noting that your cold process soap needs such a long time to cure because all the excess water must evaporate. If not, it will not work as expected.

Some recipes require less time to cure. However, it is impossible to “reduce” the curing time after the soap batch has already been made.


It’s also essential to make a balanced recipe to ensure that your soap hardens as it should. Adding too many extra ingredients such as colorants and fragrance oils can make the overall result way too softer, so using calculators can be extremely helpful if you’d like to make sure that your soap is hard but gentle on your skin as you use it.

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