Soap forensics: CRACKING

Have you ever experienced your soap to crack after molding in a couple of minutes or so? 

Take this picture for reference:

Reference: www.lovinsoap.com - They have a lot of information on troubleshootings in soap making. 

The cracking is caused by OVER HEATING. Culprit? High temperature. 

How does over heating happen in soap making?

1. High temperature lye solution

It is, indeed, important that after you have mixed your sodium hydroxide to your water, you must let the solution cool down. The ideal temperature of the lye solution upon mixing with the oils is at ROOM temperature. 

Just by touching the container of the solution, you will be able to know if it's cool enough to be emulsified with already. 

Why does this make sense? But then the batter really heats up to complete saponification, right?

The batter does heat up to a point where the temperature rises quite high but not high enough to make the soap crack in the mold. The additional temperature from different factors are the culprits to over heating then cracking. 

So,

Aside from a high temperature lye solution, what else leads to overheating?

2. Over insulation

If you are a new soap maker, you may have come across articles that suggest insulating a soap in a mold. Yes? If so, a thick layer of an insulating material may cause temperatures to rise. This is quite important for soapers living in cold areas. Since I live in the Philippines where it is actually hot, I do not find insulation important. 

Why is insulation important anyway? Insulation is important to aid in the gelling phase of the saponification process. Without gelling, the soap may not achieve the ideal color you wanted. Gelling helps in a better color but it is not really necessary. Although gelling is really part of the saponification process, a partial gel may occur if you did not insulate, which is not aesthetically appealing. It's really subjective though. 

What is partial gelling?

Photo Reference: http://gowestsoap.com/?p=182

Here above, is a product of partial gelling. It is when you stop the rise of temperature in the gelling phase by not insulating the soap in the mold or by placing the batch in the refrigerator. 

Back to the topic.

Insulation rises the temperature of the batter, which in turn, may result to cracking. 

A lesson is to not OVER INSULATE. Especially if you live in a warm area, insulation isn't necessary. 

3. Additives:

A. Sugar

Anything with sugar upon heated contributes a higher temperature. Even in cooking, caramelizing may reaaaaally burn due to the heated sugar. Temperature is at tops. So, if you add sugar to your lye solution, make sure your lye solution is still at room temperature. 

B. Fragrances

Some fragrances contribute to a lead on high temperature in soap. Choose your fragrance oils carefully. 

4. Palm oil

Many soapmakers claim Palm Oil to contibute to cracking or overheating. I'll have to experiment with it soon. 

So there. Keep these things in mind and avoid the crime of overheating! A soap crack is hard to mend. So, avoid it. 

Til the next post!

x Soap Authority