Have you ever unmolded a batch of soap and it was like unmolding Play-dough…your soap is too soft? For me personally, there is nothing worse. If I can’t unmold and cut a loaf of soap as planned, I get grumpy.

Soap is too Soft- Troubleshooting a Soft Batch of Cold Process Soap

I also get this question a ton, so wanted to write a blog post. If you have any ideas to offer or tips to share, please post in the comments. I’d love to hear about your experience with soft soap.

mixing soap

So what happened?

If it was your normal recipe that usually comes out hard…here are some ideas.

Not enough sodium hydroxide was added.

Could you have mis-measured or mis-calculated the amount of lye used? Did you double a batch of oils but forget to double the lye solution used?

Master-batching can cause issues if you don’t calculate correctly or use master-batched lye and oils in the wrong way. For master-batching directions and tips, check out my eBook, Master-Batching Oils and Lye for Soapmaking!

If you feel like you used the correct amount of sodium hydroxide, check your scale. If it is battery-run, change the batteries. Always use a scale with a wall plugin if you have one. This helps cut down on issues related to scale batteries going low.

If you did not use enough lye and are able to calculate the amount needed, you can re-batch and add the needed amount.

Could you have a sodium hydroxide storage issue? SH loves to suck in moisture from the air. When not stored in an airtight container, it will take on moisture and turn into hard chunks. When you go to measure it, you are actually measuring the sodium hydroxide + water so you will be short. Be sure to close up your sodium hydroxide immediately and make sure it is stored in an airtight container.

Too much water was used.

Could you have mis-measured the amount of water used? Did you half a recipe and forget to use less water?

Did you use your regular water amount but add another liquid, veg puree, or something similar, to your soap? For example, did you use regular water, but also add 4 oz. of milk to your traced soap? This extra liquid can create a softer soap.

If you are using a new recipe, what is the water percentage that is given? Some recipes online and in books simply use a high amount of water. Soap made with a high amount of water will simply need more time to unmold and cure. My standard water is 2 times the lye. I’ve seen recipes that use 3 times the lye and even 4 times the lye! Higher amounts of liquid will result in a softer soap.

Did your soap gel?

Gel phase will effect how hard your soap is once saponified. If your soap does not go through gel phase, it will be softer upon unmolding. It can even be soft and crumbly, with the corners breaking off in the mold upon unmolding. If your soap does not go through gel phase, you might wait an extra 24-48 hours before unmolding.

Soap that goes through gel phase is usually harder upon unmolding and can be unmolded after 24 hours of pouring.


Formulation issues.

Does your recipe contain a high amount of soft oils?

Soft oils are generally oils that are liquid at room temperature such as olive oil, castor oil, avocado, sunflower, safflower, sweet almond, rice bran…etc.  As a general rule, soap made from a high percentage of these oils will be on the softer side.  The only exceptions to this rule are olive oil and castor oil.  Soap made from a high percentage of olive oil and castor oil will cure to be a really hard bar of soap. Although high quantities of castor will harden up a bar of soap, it will also cause the bar of soap to be sticky and draggy.

Most of my recipes contain a high amount of olive oil. So although they are initially softer upon unmolding, especially if they don’t go through gel phase, they cure out to be a hard bar of soap.

If your soap contains a high amount of liquid oils that do not turn hard (such as rice bran, sweet almond, jojoba oil…etc.) then your soap will stay pretty soft. As it cures, it will harden a bit, but make sure you have coconut oil, butters, castor oil or olive oil to balance it out.

Soap made with high percentages of soft oils tends to be softer and stickier when un-molding.  Simply leave them in the mold a day or two longer before un-molding and cutting.  If you are using single cavity molds, you can try freezing them to harden and hopefully the soap will pop out easier.

Sometimes we just don’t know what has happened. Moving forward, here are some tips.

  • Run any recipes that you find online or in a book through a lye calc to make sure the recipe is correct.
  • When doubling or halving a recipe, run it through a lye calc just to make sure the new recipe is correct.
  • Use a scale that plugs into the wall. If you can’t, because of space or other issues, change the batteries regularly.
  • Store your lye in an airtight container.

What tips do you have for those with soft soap? Leave a comment!

-Happy Soaping!

Amanda Gail