Hot Process vs. Cold Process Soap (Which is Better?)
"I want to make soap," I told my husband one day. My step-daughter, Kylee Lane, owner of Luxury Lane Soap, is a pro-soap maker, and I have long loved and admired her beautiful, unique handmade soaps.
My husband had watched his daughter make tons of soap in his day, and he knew the dangers of working with lye, and the process of making soap. "Why make your own soap, when you have a daughter-in-law you can get it from?" he wondered.
My answer: Because I'm INSPIRED by her!
- Because making your own soap is satisfying and empowering
- You know what is in it, when you make your own soap
- It's creative and fun
- You get to decide the scent, appearance, and properties that YOU want your soap to have
There are many other reasons to make your own soap, and I wrote an article quite a while back on the Killer Toxins Lurking in most soaps you purchase. Being able to wash yourself and your children with pure, natural ingredients that you choose is one of the best feelings in the world. (IMHO).
You might also be interested in this article: Make Your Own Soap! My Favorite Hot Process Recipe.
Note: There are affiliate links scattered throughout this article. If you click through and make any kind of purchase, I will receive a very small commission at no extra cost to you. Thank you for helping support Healing Harvest Homestead---Heidi
But Which Method is Best? Hot Process or Cold Process Soap?
My daughter-in-law mostly makes cold process soaps, and they are amazing! So when I became inspired to try my hand at making soap for Mr. V. and myself, cold process soap was the kind I made first. Then I tried making hot process soap. Here are the pros and cons of hot process soap making versus cold process soap making based on my own experiences with each method.
Hot Process Soap vs. Cold Process Soap
Which to choose? Is it better to make hot process soap or cold process soap? If you look at most of the soaps being sold by artisan soap makers these days, it appears at first glance that cold process soap must be superior to hot process soap. However, there are some factors that are very distinct between hot process and cold process methods, and you might just change your mind, no matter which one you like best right now.
The Cold Process Method of Soap Making
Pros of Cold Process Soap Making (Positive Factors)
1) You can Make Some Truly Beautiful Soap
After you have become skilled at making basic cold process soap, you can really let loose and make some beautiful bars. You can swirl the top of the soap, layer colors very easily, and easily embed flower petals and other items in the tops.
2) Cold Process Soap Making Takes Less of Your Time to Make
Essentially, all you need to do is bring the lye+oil+liquid mixture to trace, then pour it into the soap mold. Then you wait.
In essence, the actual amount of physical time you spend working with cold process soap is less than with hot process soap.
Cons of Cold Process Soap Making (Negatives)
1) SUPER Long Cure Time
It takes a LONG time to cure cold process soap---about six weeks, to be exact. This means that you can't use it until the chemical reaction is complete and the lye has left the soap all the way. You have to cut it after it cools in the mold (about 24 hours), then put it someplace safe out of the way of children and pets so it can cure quietly for several weeks before you can use it.
2) More Finicky Temperature Requirements
You have to watch the temperatures of the oils and water when you are making cold process soap very carefully. Both oils and liquids need to be within about 10 degrees of each other for the soap to work best.
3) The Scent Doesn't Seem to Last as Long
In my experience, the scent in cold process soap fades much more quickly. I use essential oil, so maybe this has something to do with it, but I have to other hypotheses for my observations.
The first is that you have to cut the bars to cure them for the several weeks. This means there is a lot more soap exposed to the air, which creates an environment for the essential oils to evaporate more quickly.
You also can't use the soap for weeks, and in those weeks, the scent dissipates a bit too. It may not be significant, but I can tell the difference.
You need the room to store your soaps while they cure. Since they are still caustic while curing, you need to keep them away from children and pets for safety reasons. Therefore, you'll need to plan on a dedicated spot for your soaps as they finish becoming usable bars.
The Hot Process Method of Soap Making
Pros of Hot Process Soap Making (Positive Factors)
1) Temperature is not as Finicky
With hot process soap making, your oils and lye solution will be heated in a crock pot. Therefore, the temperature of the oils and lye is not as important. What I've found is that I can almost just pour them together, even though the lye solution is very hot, and bring them to trace in the crock pot. This alleviates the need to take temperatures.
One caveat: I do let the lye solution cool down while my oils are melting in the crock pot. This seems to cool it enough so that I have never had a problem with the mixture being too hot. The one exception was when I made goat milk soap in the crock pot, and it did get too hot. I had to re-emulsify it during the cook.
2) Your Soap is Ready Right Away (Immediate Gratification, Anyone?)
I love that I can use my soap right away. LOVE, LOVE, LOVE this! I know right away how it turned out, and I get to experience my little experiment the very next day!
One thing to know: Although you can use your hot process soap right away, it will harden up more after an extra week or so of sitting. Frankly, we don't go through three pounds of soap all at once, so my soaps tend to sit for perfect lengths of time anyway.
3) It's More Traditional!
Even though you are using modern tools (crock pot, hand blender, digital scale, etc.) hot process is how soap making took place back in the day! Women would toil laboriously to stir a large pot of soap ingredients over a hot fire.
So, even though we now get to use a crock pot and other tools (isn't that awesome), it's truly more of a traditional way of making soap.
I like to think that if the grid went down, and there was no more electricity, I know enough about hot process soap making and the stages it should go through, that I could probably get some hard-wood ash and figure out how to make my own..... I like to think this anyway. ;-)
4) The Scent Lasts Longer Than Cold Process
I've found the soap is fresher, and the scent remains stronger over time with the hot process method.
Because the soap is ready right away, you don't have to cut it immediately into bars. You can let an entire loaf of soap sit for weeks. This means that the interior of the soap is not coming into contact with the environment, and the scents remain stronger for longer in hot process soap.
5) You Can Make Hot Process Look (Almost) Like Cold Process Soap
I have discovered that if I wait about an hour after I've poured the soap into the mold, I can cut the top off the hot process soap. This leaves a nice, smooth top. Once the bars are cut, all the sides and top look just as smooth and beautiful as cold process soap.
There are ways to get swirls in your hot process soap, too, but they won't be as calculated as you can do with cold process soap making.
Cons of Hot Process Soap Making
1) It Takes a Little More Time
Because you have to wait while the soap cooks, do some stirring, and wait a bit more, there is a greater initial time factor with hot process soap making. It takes about 45 minutes to an hour longer, I'd estimate, because you have to wait for the "cook".
2) Not as Attractive Bars of Soap
This is debatable, in my opinion. Yes, I love the smooth and cultured look of cold process soap. But I have made some absolutely delightful looking bars of hot process soap, too!
Because hot process soap is malleable during the cooling phase, and you can touch it since it's not caustic---you can make soap balls with the cut off loaf top!
Gosh---I think I just turned this negative into a positive?
At any rate, there are a lot more options in changing the appearance and making designs with cold process soap making.
Final Thoughts on the Hot Process vs. Cold Process Soap Making Debate
It may appear that I'm biased toward hot process soap making, but that's not actually the case. I think all these things have different values for different folks.
For example, time is not an issue to some people, and I know many people who don't mind waiting for a few weeks---plus your house will smell lovely during this time.
On the other hand, some people (myself included) don't mind a rustic looking bar of soap at all. I personally find intrinsic beauty in the different results of hot process soaps.
It's all about what YOU want!
One thing I can say is that I am so very glad my daughter-in-law inspired me to start making soap. It's been a creative and wonderful gift to learn how to do this. I'm also grateful to have a husband who may think I'm crazy but supports the things I want to try!
Do you make soap? What are your experiences? Which do you prefer--hot process or cold process soap? Leave comments, questions, etc. in the comments section! I always reply, and I appreciate you for reading!
Hugs & Self-Reliance,
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