CP Soap Curing time Speed up Possible??

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Sahil Doshi

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Hey all!

I was once reading an article about a lady who mistakenly put her fresh batch of CP Soap in her microwave oven and 'cooked' her soap in the preheated oven and apparently was able to wave off 3-4 weeks of curing time.

This got me thinking about the benefits of curing of the soap naturally:
  • Allows water to evaporate so that bar becomes harder: Now, evaporation of water depends on the following factors namely: relative humidity, temperature of soap, temperature of surrounding, speed of air flowing through. Now, for example, I have a set of 8 soaps spaced out without them touching on one of those cake cooling racks and I have a hair dryer blowing towards the soaps from the 4 directions. Here, we know for sure that the air will be a lot more warmer and the speed of the hot air is also quite high and the relative humidity is low since I have hair dryers blowing out hot air.
  • Reduction of pH: Now, pH is basically the amount of H+ ions in any material. I did my research and there is a direct correlation between the temperature of a material and its pH. What I figured from it was that as temperature increases, the pH goes down. So, the same hair dryer example as above will also fit to reduce the pH.
  • Makes the bar more milder: When the pH of the soap will go down, automatically the soap will be a lot more milder and a lot more softer on the skin.

So, potentially, it is possible to mechanically reduce the curing time of CP soaps by putting them in some sort of dryer. Maybe a bigger sized version of a toaster maybe??? A lot more lower temperature, maybe something around 40C - 50C. With internal fans for air movement

What do you'll think of this? Do you'll think its possible??
 

lsg

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Water evaporation does not mean a soap is cured. As a soap cures, it gets milder and longer-lasting. You can use sodium lactate, stearic acid or even salt in the lye water to make a harder bar, but that doesn't mean it will last or is a mild bar. I have never heard of anyone mistaking a microwave for a regular oven.
 
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My favourite example in this is a Castile bar. At 1 month it has probably lost most of the water which it will lose. At 3 months there won't be massive changes in the water amount going forward. And yet the difference between a 1 month or a 3 month bar when compared to a 12 month old bar is "yuge".

Why?

It can't be down to water loss. At these points, the soap will have its pH and that is pretty much that. Time won't play a big factor in it.

So what is it?

Soap is never really solid. Even a bar that can be used as a hammer is not physically speaking a real solid. It has a crystalline structure which forms over time which has potentially far more impact on the performance of the bar than anything else.

That is not sped up by quick drying in any way. In fact, I wonder if force drying a bar might well hinder the long term crystalline structure formation to an extent that a bar left to its own devices would be better at 3 months than a bar which had been "speed cured". Would be an interesting experiment
 

DeeAnna

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Yes, pH is affected by temperature, but it's a two way street. What did your research tell you about what happens to pH when the temperature drops? Also, just how much of a pH drop do you expect to get from your plans?
 

dixiedragon

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I don't know of a way to speed the crystalline structure and I would think that is something you'd need a lab to examine. I have been playing around a bit with "twice baked soap" - and I've been wondering what would happen with repeated bakings?

I do think that cold tends to slow everything down - for example, I think freezing soap slows the cure - so I would suggest a warm, dry room (use a dehumidifier, perhaps) with good circulation would be a good first step towards speeding up cure.
 

Sahil Doshi

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This was actually my mistake. What I meant was an oven.

Yes, pH is affected by temperature, but it's a two way street. What did your research tell you about what happens to pH when the temperature drops? Also, just how much of a pH drop do you expect to get from your plans?

In case the temperature reduces, it makes the pH increase. Also, in case of pure water, the pH recorded at 0C was 6.14 and the pH recorded at 100C was 7.47
 
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DeeAnna

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The implication in your original post is that the pH would be permanently reduced. I wanted to make sure you didn't think that was really going to happen.

Remember too that water is not a buffer nor is it a salt. Soap is both. So you cannot assume what happens with water also happens with soap.
 

Sahil Doshi

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The implication in your original post is that the pH would be permanently reduced. I wanted to make sure you didn't think that was really going to happen.

Remember too that water is not a buffer nor is it a salt. Soap is both. So you cannot assume what happens with water also happens with soap.

Quite True.. Thats an interesting point..
 

Barmaid

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I believe what you are referring to is CPOP soap, soap that is cooked in the oven. A hot processed soap. Hot process soaps often cure a bit faster than cold in my experience. If you are looking for ways to speed up curing, that is, at least the water evaporation part, I would suggest simply starting with less water (by using a water discount, don't go too crazy if using hot process) and keep good notes weekly on weight (I mark one bar from each batch and weigh it weekly until it no longer changes, usually about 4-5 weeks, I usually lose .05-.1 oz from each bar per week) so that you can get a good understanding of how much water you are losing from each bar. When you make soap again, you can start with a bit less water each time. After the cook and cut all you can do is be patient, supply really good air flow and run a dehumidifier.
I think if you run hot air over them all of the time, you could end up with some minor problems, like DOS. I do not know that for sure, but it is something that came to mind when you said that.....so if you do try it, I would love to know, good results or bad!
 

Kari

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Water evaporation does not mean a soap is cured. As a soap cures, it gets milder and longer-lasting. You can use sodium lactate, stearic acid or even salt in the lye water to make a harder bar, but that doesn't mean it will last or is a mild bar. I have never heard of anyone mistaking a microwave for a regular oven.

huh, I was under the impression that the saponification process happens fairly quickly, and that your cold process bars are 'safe' to use after a couple of days. (this is why hot process is considered faster, since you're using heat to speed up the saponification) Curing is intended to make the bars harder and longer lasting - which is a result of water evaporation.

Does cure mean something else outside water evaporation?
 

dixiedragon

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huh, I was under the impression that the saponification process happens fairly quickly, and that your cold process bars are 'safe' to use after a couple of days. (this is why hot process is considered faster, since you're using heat to speed up the saponification) Curing is intended to make the bars harder and longer lasting - which is a result of water evaporation.

Does cure mean something else outside water evaporation?

Yes, it's more than just evaporation.
https://classicbells.com/soap/cure.html

IMO, 1-day old HP soap is a bit milder than 1 day old CP. However, both still need at least 6 weeks. If it were just about water evaporation, then people would be soaping with the lowest possible amount of water in order to speed cure. Cold process is "safe" to use as soon as it doesn't zap, but safe doesn't mean pleasant. Wash your hands with some week-old soap - CP or HP - and then compare to some 8 week old soap.
 
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huh, I was under the impression that the saponification process happens fairly quickly, and that your cold process bars are 'safe' to use after a couple of days. (this is why hot process is considered faster, since you're using heat to speed up the saponification) Curing is intended to make the bars harder and longer lasting - which is a result of water evaporation.

Does cure mean something else outside water evaporation?
Here is a great place to start reading about cure written by our own DeeAnna the chemist :D Oops Dixidragon was faster than me with the info
 

jcandleattic

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To me the original post is mistaking "cure" with "saponification" which happens all the time. Once there is no active lye remaining in the soap, is has fully saponified. It will still need a full 4-6 week cure. Two completely different terms in soapmaking to mean completely different things. It's a common mistake.
 

Kari

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A lot of this seems to do with the types of oils used. Lard takes longer to trace, and olive oil is slow to trace - both are used as examples of soap that get distinctly better with age. That makes sense since this is all chemical reactions and if you change up the ingredients, your reaction will change as well.

I am curious if anyone had actually tried to speed up the cure.. and if it were possible to speed it up - if you would end up with a bar whose quality is equal to that of a bar left to sit for 8 weeks or more. The one challenge I can imagine is having a control.. since in order to get an apt comparison you'd need to still let the one bar sit for the full number of weeks.
 

jcandleattic

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I am curious if anyone had actually tried to speed up the cure.. and if it were possible to speed it up
This is an age old question, and the answer IMO always circles back to - no, there is no way to speed up cure time.
Curing is more than just one single thing, and requires time. It's water evaporation along with a distinct chemical change occurring within the soap, and it's that chemical change that requires the time.
If it was simply about water/liquid evaporation, then a 50/50 lye solution soap could be cured within a matter of days, but it is so much more than that.

Someone asked me if they could put it in a Dehydrator .. :beatinghead:
That's because many people think curing is simply liquid evaporation. But it's so much more than that...
 
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dixiedragon

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Actually, putting it in a dehydrator could make sense. I doubt it would speed up the crystallization, but if you live in a humid climate it would definitely help speed up the evaporation process. And I would think (just guessing here) that dryer soap would be less prone to DOS?
 

jcandleattic

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Actually, putting it in a dehydrator could make sense. I doubt it would speed up the crystallization, but if you live in a humid climate it would definitely help speed up the evaporation process. And I would think (just guessing here) that dryer soap would be less prone to DOS?
In almost every case of hearing about people doing this it "ruined" the soap. AKA melted it, warped it, made it drippy and sticky.
I've never once heard a success story about putting soap in a dehydrator.

But, I have no first hand knowledge so can only relate what I've read/heard from others.
 
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Actually, putting it in a dehydrator could make sense. I doubt it would speed up the crystallization, but if you live in a humid climate it would definitely help speed up the evaporation process. And I would think (just guessing here) that dryer soap would be less prone to DOS?
Most if not all dehydrators use heat and it will melt the soap. I tried this when I first starting soaping and my dehydrator goes low in heat but it still melted the soap or at least softened it severely. Mine goes as low as 95º F
 

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