Why and How of Curing Soap? (2024)


Some of my clients asked me:
Why does it take so long, after you made a soap, to add it to the store?
In this blog I will explain why it takes more than a month for a soap to be ready, available in the store.

What is a soap?

Soapis a salt produced by the chemical reaction, called Saponification, between fatty acids and an alkalimetalhydroxide, such as sodium or potassium. During this reaction, the triglycerides are broken down into their component fatty acids and neutralized into salts by the sodium hydroxide. Cold Process Soap is the result of this chemical reaction.

When we make soap, we are using water or milk to which we add the Lye (Sodium Hydroxide). After we make the Lye Solution, we add it to the oils. In this way the Saponification happens and the result is the Soap. To be safe for our skin to use the soap, it has to go through a process of curing.

What is Soap Curing?

When we are making soap we use distilled water or milk to dissolve the Sodium hydroxide (lye), which is needed for producing the soap. When we take out the soap from the mold, it still contains water and lye. This is why the soap needs a period of time, called curing, to allow it to be in the best condition to be used. Otherwise, the soap bars will not last, turning to paste when they are handled.

Curing is the process of allowing saponification to complete and for water to evaporate out. In this way, the soap, is dry, harder, milder and the lye non-existent in the finished product. It takes about 4 to 6 weeks for a soap to dry and the lye to be totally transformed. The time we leave your soap to cure depends on the oils and percentage of water used in the recipe. When we use a recipe with discounted water, 4 weeks may be enough for the curing process. If we are making a soap with a more complicated design, such as a swirl, and we are using a recipe with larger content of Olive oil, then we wait for, at least, 6 weeks. Olive oil takes longer to be saponified and to harden up.

How is the soap cured?

Why and How of Curing Soap? (1)

Soap in the mold

Why and How of Curing Soap? (2)

Cut soap 36 hours after it was made.

Once the bars are un-moulded, sliced and set on the shelves (racks), the curing period starts.

The place where the soap is cured needs to be an airy, out of direct sunlight, and a dark place. These conditions will also help to preserve the scent. Sometimes, if we make more soaps and do not have enough room for them, we use stackable metal racks.

Why and How of Curing Soap? (3)

Soaps made on the 17thand 23rdof March waiting for the Curing period to pass.

Every couple of days we turn them for every side to be cured properly.

Why and How of Curing Soap? (4)

Metal stackable racks for curing soap.

On the shelves or racks, the soap bars have to be spaced, for the air to circulate around them. To be sure that we know exactly when the curing period is ending and when we have to start packing our soaps, we add a curing card, to each batch of soap we make.

Why and How of Curing Soap? (5)

This template of the Cure card is offered

We mark the soap’s name, the date when the cure period starts and when it ends, the total weight, and some notes.

Why is the curing process necessary?

There are a few things that can go wrong if the soap is not properly cured. First of all, it, still, contains lye. Even though the saponification of Cold Process soap is mainly complete in the first 48 hours, there is, still, a chance that the soap bars will contain lye for up to a month. To avoid skin or eye irritation, the handmade soap needs to go through all this period of curing, before it is used. Also, the curing period will ensure that the bar of soap will last longer and will not disintegrate in contact with water.

Anyway, to have a handcrafted bar of soap for as long as possible, it is recommended to use a soap dish that allows draining, between uses.

Only after the curing process is ended the soaps can be packed and labeled. Otherwise, the condensation and moisture created by the un-evaporated water will destroy the packaging.

Methods to reduce the curing period

Water discounting method means that we use less water to make our lye solution. For example: we can use more than 33% lye concentration for our soap. There can be use an equal amount of lye and water (which is the minimum amount of water), but this drastic water discount can be used only by advanced soap makers. The risk is, for a beginner, is that the high lye concentration will speed up the trace and the soap batter will harden, very quickly, becoming unworkable.
Using a dehumidifier, in the place where we are curing the soaps, will reduce the curing period. If it rains a lot and the humidity is high, we use a dehumidifier in the space that we are making the soap.

When is the soap ready for using?

We always weight the soaps before we arrange them on the shelves. In this way, we observe, regularly, how much weight they lose. When they stop losing weight, it means that they probably are ready and the curing period is ended.
Some soap makers accelerate the curing setting their soaps outdoors, in warm and dry weather. Even if we would live in a place with warm and dry weather, I do not think that we will use this method because of the dust and impurities that may touch our soaps.

I hope that this blog gives you some insight into the timeline of the soap making process.

Do not forget – Good things take a little longer, but they are worth waiting for!
If you would like more information, please, do not hesitate to write us at:

Why and How of Curing Soap? (2024)


Why and How of Curing Soap? ›

For cold-processed soap, it's more a form of finishing. For the 4-6 weeks it takes cold-processed soap to cure, there's a slight bit of pH finalizing, but mostly, curing consists of a physical action – evaporation – during which the bar becomes harder as it loses water.

Why do you need to cure soap? ›

When you make soap, you combine water and sodium hydroxide (or you can use our premade sodium hydroxide solution and skip this step). The longer your bar cures, the more water is evaporated, creating a denser, harder, and longer lasting bar of soap.

What happens if you don't cure soap long enough? ›

If you use your soap before it has fully cured it will dissolve more quickly not just because it has a higher water content but because not all of the longer chain fatty acids have formed soap crystals at that point and it is the crystalline component of soap that is predominantly made up of longer chain soaps which ...

What is the best way to cure soap? ›

The best environment for them to cure is a cool, dry place out of direct sunlight. A few options include your garage, basem*nt, or a large cabinet. Here at Bramble Berry, we use large bakers racks. The soap gets plenty of airflow, which speeds up the curing process.

Does homemade liquid soap need to cure? ›

Do liquid soaps need curing? Liquid soaps don't need curing in the same way as bar soaps for several reasons. First, liquid soaps are pretty much always made by hot-processing. The finished soap paste will normally have already completed the saponification process.

Can you use homemade soap right away? ›

Curing: Technically, cold process soap is safe to use after a few days. However, we recommend letting the soap cure for 4-6 weeks in a cool, dry place with good airflow.

Do you cut soap before curing? ›

A few days to one week after you've made your soap you can unmould it and prepare it for the curing process. If you made salt soap better cut it one day after you made it as it can become very hard very fast. During the 4 to 6 weeks of curing the saponification will finish and the soap will become milder.

Can I use soap without curing? ›

1) no, as long as the soap has saponified it is safe to use - once saponified there should be no active lye present. The soap will probably be harsh and drying though, if used before a full cure, and it will also dissolve much quicker than a fully cured soap.

What is the zap test for soap? ›

Then you can do the "zap test." It involves tapping the soap lightly on your tongue. It sounds weird, but it totally works. If the bar “zaps” you, it's likely lye heavy. The feeling is hard to describe, but you'll definitely notice it.

Why is my soap sweating while curing? ›

Natural soap, with its glycerin retained, can attract humidity due to climate or where it's stored. Especially in humid climates, sweating can be an issue. The best advice is the simplest: Let your soap harden and cure at natural room temperature and then store in a cool, dry place.

What ingredient makes soap last longer? ›

Sodium lactate acts as a humectant, attracting and retaining moisture, ultimately increasing the soap's hardness. Incorporate it at around 1-3% of your oil weight for optimal results. Boost the firmness of your soap by adding beeswax or other waxes.

Why is my soap not curing? ›

There are several factors that will affect the cure time such as ajusting the amount of water or adding sodium lactate. Getting the recipe wrong or measuring wrong will have negative effects. If you aren't positive about the recipe run it through a calculator such as the one at SoapCalc Home .

How can I speed up the curing process of soap? ›

So now that we've established that, let's consider some techniques that could get your bar of cold or hot processed soap to cure quicker.
  1. Run a dehumidifier or air conditioning. ...
  2. Keep some Damp Rid or zeolite rocks as close as possible to your curing rack. ...
  3. Maximize air circulation.

Why isn't my homemade soap hardening? ›

The more soft oils (such as olive, sweet almond, rice bran, canola, etc.) the soap contains, the softer the bars will be. It may take more time to harden in the mold. The more hard oils the recipe contains (such as palm, coconut, cocoa butter, beeswax, etc.), the quicker the soap will harden.

How long should homemade soap cure? ›

I'm more of an observer when it comes to various social media groups devoted to all things wonderfully sudsy, but the three most common answers I've seen to this age-old question include, #1: “You can use your soaps in 4 to 6 weeks.” (Which doesn't offer an explanation as to why.); #2: “It's not safe to use cold ...

What not to do when making soap? ›

Making Soap with Lye: 7 Must-Know Safety Rules
  1. Use Only 100% Lye. ...
  2. Wear Gloves and Protective Goggles. ...
  3. Always Pour Lye Into Water, NEVER the Other Way Around. ...
  4. Don't Use Aluminum Pots or Utensils. ...
  5. Use Heat-Safe Plastic Containers for the Lye water Mixture (Not Glass) ...
  6. Use Cold Water. ...
  7. Set Your Lye Water Container in the Skin.

Why is it important to cure soap? ›

This is why the soap needs a period of time, called curing, to allow it to be in the best condition to be used. Otherwise, the soap bars will not last, turning to paste when they are handled. Curing is the process of allowing saponification to complete and for water to evaporate out.

Does homemade soap go rancid? ›

Handmade soap is made from fresh ingredients. Soap that is not stored properly can go rancid! Your soap may also have dreaded orange spots, glycerin dew, faded colors, and/or scents.

Does soap base need to cure? ›

The base is produced through the “saponification” process, which involves mixing fats and an alkali (such as lye). The resulting substance is allowed to cure for up to four weeks before it's ready for use.

Can you use uncured soap? ›

Soft, uncured soap can disintegrate quickly if you get it wet and have impaired lather. Young soap bars that are a week or two old can technically be used—both cold-process and hot-process. However, they won't lather, clean, be as gentle, or last as long as soap that is fully cured or older.

Does homemade soap go bad? ›

Handmade, natural soaps tend to have a shorter life-span, purely because natural ingredients generally 'go bad' sooner than artificial ones. This is one of the reasons that natural, handmade soaps are often smaller than the mass-produced soaps manufactured by large companies.

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