Lye & Oils Temperatures while making cp soaps

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silver angel

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Hi everyone. Im a newbie here and want to know about a question regarding Lye and Oils temperatures. I know that most of the brilliant and kind soapers have already discussed on this topic. But I always get confused about the temperatures. I live in a humid place and my simple question is
Is Lye temperature must be lower than Oils temperature? YES or NO?

Thank you in advance and plz forgive me on asking this stupid question but believe me your support will make my path easy in cp soap making.
 

ResolvableOwl

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Welcome to SMF, @silver angel !

As you might have guessed, people have different opinions on this (and with different degrees of enthusiasm for caring about it at all); understand my opinion as not an exception to this:
NO, please DON'T use lye that is COLDER than oils. Especially don't use lye when it is below the melting point of your higher-melting ingredients (hard oils, waxes etc.), because that is likely to bring you in trouble with false trace issues. If the lye is warmer than oils, this is usually no issue – in the end, it's the temperature of the mix that matters for how quickly moving your batter will be (heat will speed up the reaction). The temperature equalisation between oils and lye is a matter of mere seconds even when you're just stirring with a spatula.
 

silver angel

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I dont have words to say a BIG THANK U for your quick reply and understanding my situation :)

I usually wud keep my LYE solution temperature lower (5 centigrade) than OILS but now im clear that LYE solution must be warmer than OILS.

Stay BLESSED :)
 

TheGecko

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Is Lye temperature must be lower than Oils temperature? YES or NO?

It depends. I MasterBatch (pre-mix oils/butter and Lye Solution) and my Lye Solution is often cooler, as much as 30F to 40F cooler than my Oils and I've never had an issues, BUT...I've also been making soap for 2 1/2 years now.

As a new soap maker, I was taught that my Oils and Lye Solution HAD to be 110F, then I was told that my Oils and Lye Solution HAD to be within 10 degrees of each other...didn't matter which direction. A lot of this was less about some hard and fast rule and more about keeping the beginner safe and successful.

The REALITY is...it all depends on your recipe, your skill level and your average temp.
 

gww

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I am super new and only made about ten batches give or take. To be honest, I don't know the right or wrong but do know that I put my lye water in my oils the minute that it has cleared and I know is dissolved and while the cup is very hot. I put it in cold oils and let it melt the oils. So far the soap seems to turn out fine but I am doing nothing fancy or adding any color or scent.
I did it this way cause all the reading and watching videos were hurting my head and so I picked the very easiest video and when it worked, have just been rinsing and repeating. I will also say that the people responding to this thread have helped me and explained things I wanted to know and I could not be more thankful for that and you are in good hands, my post not being counted in that.
Cheers
gww
 

ResolvableOwl

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I put my lye water in my oils the minute that it has cleared and I know is dissolved and while the cup is very hot. I put it in cold oils and let it melt the oils.
For some reason this is commonly called “heat transfer method”, and quite some soapmakers do it regularly. It is the most “efficient”/“ecological” way because the heat that is inevitably emitted during dissolving NaOH is used to do something useful (melt up solid oils) rather than just wasted. I personally feel uncomfortable to overestimate the amount of heat from the lye (hence, risk to end up with solid chunks of oil still swimming around in a batter that is already fully into saponification). I wouldn't recommend it to beginners, but won't deter those who find that it works for them.
 

TheGecko

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I personally feel uncomfortable to overestimate the amount of heat from the lye (hence, risk to end up with solid chunks of oil still swimming around in a batter that is already fully into saponification). I wouldn't recommend it to beginners, but won't deter those who find that it works for them.

I’m guessing that you have never used the Heat Transfer Method. Julie at Ophelia’s Soapery uses it quite often…here is a current link:

You will note that she has all her oils, soft and hard, in her container before she adds in her freshly made lye. She stirs for about five minutes then uses her stick blender to break up some of the remaining butters, stirs more until fully melted, and then stick blends until it is emulsified. Note how fluid her batter is…no solid chunks of oil swimming in ‘soap’. Then she adds in her FO, stick blends some more…the batter is still very fluid as she separates for colors. She whisks her colorants her, then goes back and stick blends and you will note that she has finally reached a light trace. She then drops both colors into her main pot and pours…batter is still fluid. Her batter is about a medium trace when drops the excess batter on top, but is still able to get a fluid swirl on top.

When she first started using the HTM, she just poured the fresh lye over her hard oils, melted them, then added her soft oils. This was the same technique that I learned from Jen at Be Scented. While I mainly Master Batch my Oils and Lye, there have been many occasions when I’ll make a soap from ‘scratch’ or run out of Lye Solution and use HTM.

Technically the ‘saponification’ process starts the minute you pour your lye solution into your oils…the lye starts to immediately bind with the oils. I really didn’t pay much attention to it until I started making my Lye Solution with 100% Goat Milk and could see the Lye binding with the fats in the milk.

This article was very helpful for me! Check it out!


This is not an article that I would recommend to beginning soap makers and there are a few things that I don’t agree with.

First is the temperature of her Lye Solution…it’s too low. @DeeAnna can give you the exact science of why your Lye Solution shouldn’t go below about 70F.

Second, I soap at cooler temps…around 80F to 90F and I Master Batch. But even during the summer when my MB oils are like pancake batter, I still remelt them to about 100F-110F. It’s okay to have oils that are slightly cloudy, but you don’t want them thick and slushy, especially if you are using hard oils heavy with stearic acid…unless you like having Stearic spots in your soap. The only time I don’t remelt my oils is if I am using freshly made lye (200F-220F).

There is no ‘sometimes’ about false trace occurring…it will occur. And it’s not going to go away as easily as described…it’s takes more than just a bit of movement with your spatula to generate the heat needed to melt the oils. And notice she is using a stick blender in her photo, not a spatula. I’ve made soap with a spatula…took a soaping class. Mind you, our oils and Lye Solution was about 100F and it took a lot of ‘movement’ to get it to trace.
 

ResolvableOwl

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I’m guessing that you have never used the Heat Transfer Method.
Yes I haven't. But then, I won't try it any time soon, as long as I want my process to be reliable at batch sizes around 100 g oils, i. e. some 14 g NaOH dissolved in 30 mL water. With that small volumes, heat losses to evaporation and conduction are much more severe than with production-size batches. And also don't underestimate my masochism to work with difficult-melting hard oils like canola wax, triglyceride-type palm stearin, japan wax, or ucuuba butter.
And lye masterbatching makes heat transfer pointless anyway.

There is no ‘sometimes’ about false trace occurring…it will occur.
Well, there are exceptions (e. g. 100% olive), but that article completely fails to acknowledge that it heavily depends on the recipe, which temperatures are workable and which aren't. Looking at the photo of her oils, this is at least an invitation to stearic spots. I don't want to rely on reaction heat to fix false trace, nor recommend this to people who don't have the experience to tell apart false from true trace. I can't always either.

First is the temperature of her Lye Solution…it’s too low. @DeeAnna can give you the exact science of why your Lye Solution shouldn’t go below about 70F.
That cold of a lye isn't just dangerous, it is also pointless. Unless it's winter and you are soaping in a garage, you would have to actively cool the lye in a fridge. And lye doesn't spoil, it just would waste space in the fridge.
That article really sounds like complementary to her CP pine tar soap, where it indeed might be advantageous to tame the “bite” (emulsification effect & heat of neutralisation from free resin acids) of the pine tar.
 

TheGecko

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Yes I haven't. But then, I won't try it any time soon, as long as I want my process to be reliable at batch sizes around 100 g oils, i. e. some 14 g NaOH dissolved in 30 mL water. With that small volumes, heat losses to evaporation and conduction are much more severe than with production-size batches. And also don't underestimate my masochism to work with difficult-melting hard oils like canola wax, triglyceride-type palm stearin, japan wax, or ucuuba butter.

And lye masterbatching makes heat transfer pointless anyway.

What seems pointless is spending an hour to make a single, small bar of soap. How do you adequately test it? My Test Batches are 14oz (453.59g) of Oils...this gives me 4-5oz bars. One bar is my control bar...it stays untouched for eight weeks (my minimum curing time). It is then examined, weighed and smelled; it then goes back on the shelf and checked again at twelve and twenty-six weeks. The other three bars are cut in half and cured for eight weeks and five are sent out to my testers who live in different parts of the US to not only test the qualities of the soap, but also to see how it does in different climates. Each bar comes with self-addressed, pre-paid postage postcard that each tester fills out and drops in the mail. My testers do not know exactly what they are testing...a new ingredient, a new colorant, a new scent. It's a pain in the butt process since it takes so long (at least three months), but my goal is to make soap for every body, not just myself.

True, you can't use the HTM if you MB a ready-to-use Lye Solution, but I don't always use my MB Lye Solution or Oils.

.....that article completely fails to acknowledge that it heavily depends on the recipe, which temperatures are workable and which aren't.

Which I mentioned: especially if you are using hard oils heavy with stearic acid

That cold of a lye isn't just dangerous, it is also pointless. Unless it's winter and you are soaping in a garage, you would have to actively cool the lye in a fridge. And lye doesn't spoil, it just would waste space in the fridge.

Lye (NaOH) does 'spoil'...which is why folks are advised to 1) NOT refrigerate their Lye Solution, and 2) to keep their Lye Solution and/or Sodium Hydroxide in a tightly closed container. As noted by @DeeAnna you want to keep your Lye Solution at least 65F/18C as "the sodium hydroxide will precipitate out (become solid) when the mixture gets too cold". Lye Solution and/or Sodium Hydroxide that is exposed to the air "will absorb water from the air and react with carbon dioxide gas in the air. Both of these things will reduce the concentration of NaOH, which is not good."

I know both of these to be true as I have done both (this was before I found this forum).

That article really sounds like complementary to her CP pine tar soap, where it indeed might be advantageous to tame the “bite” (emulsification effect & heat of neutralisation from free resin acids) of the pine tar.

Agree, since it says that in the first paragraph: "This is the soap method you should use to make Pine Tar soap, as the cooler temperatures allow you more time to mix your soap."

I've never made it, have no real interest in making it because while I plan to dip into the Cosmetic side of Bath & Body, the Drug side is too problematic as I am just a small soap maker. In the US..."drug claims" require licensing and oversight of the FDA (Food & Drug Administration), and it would undoubtedly require more expensive insurance. And without the FDA, I'd never be advertise or talk about the whole purpose of using Pine Tar...so why bother.
 

ResolvableOwl

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you want to keep your Lye Solution at least 65F/18C as "the sodium hydroxide will precipitate out (become solid) when the mixture gets too cold".
I agree, and want to add an important bit of context to this number: lye concentration. It is the 50% masterbatch that separates just below room temperature, as correctly remarked by @DeeAnna as well as the under-appreciated lab assistants who have experimentally determined the full water/NaOH phase diagram many decades ago.
For a 30% lye solution, the precipitation temperature drops to roughly 32°F/0°C. If someone insists on storing such a ready-to-use lye in the fridge, it is technically possible – yet still has zero advantage over room temperature storage (rather, downsides like condensation, false trace (if not heated before usage), occupied fridge space).

What seems pointless is spending an hour to make a single, small bar of soap. How do you adequately test it?
FWIW, the boundary between sensible and pointless is everyone's own decision. Making soap is pointless all in all, since you can just buy it (much quicker than making it from scratch!). The soapmaking decision also depends on many factors of personal situation which we don't know all (and don't have to know).

Even if I by far cannot compete with your crowd-sourced blind-test protocol (😍, btw!), I don't think I'm doing terrible injustice to my recipes, when I give them two or three weeks of washing hands/showering, divided into a few sessions across some months, to form a distinct opinion on it; and in case something goes wrong or I don't like it, I don't have to worry about many surplus bars.
 

TheGecko

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Even if I by far cannot compete with your crowd-sourced blind-test protocol (😍, btw!), I don't think I'm doing terrible injustice to my recipes, when I give them two or three weeks of washing hands/showering, divided into a few sessions across some months, to form a distinct opinion on it; and in case something goes wrong or I don't like it, I don't have to worry about many surplus bars.

Agree with the rest so saw no need to copy. Thanks for the explanation of how you test you soap.

I don't have a surplus either...I did in the beginning when I only had the 10-bar mold, but after having a toss a few batches, I quickly bought a couple of smaller molds. The 'crowd-sourced'...I don't if I would call a few old friends and classmates a 'crowd'. LOL It was when I decided to turn what was originally going to be a hobby for family into a business that I decided it would be a good idea to see if others liked my soap too so I did a 'shout-out' on my social media and took the first six people who responded...who just happened to live in different areas of the country.

At the time, I had four different recipes I was wanting to test and since I didn't want any pre-conceived ideas or expectations based on ingredients...I colored each one a different Mica with corresponding color postcard. I did check ahead of time to find out if anyone had any allergies or sensitivities.
 

TheGecko

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which is brilliant, because different areas = different water hardness!

And different kinds of environments. I've lived all over the US and I know that environment can play havoc on things from storing clothing, cooking, baking, skin, hair, etc...so why not something as simple as soap. Right now, I live in the Pacific Northwest in the US...during the winter we get a lot of rain...it's just damp, cold and fairly cloudy. It affects my soap making. I have to cure my soaps an extra four weeks and I have to go from a 33% Lye Concentration to a 35%.
 
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I don’t find it to be true that your oils must be cooler than your lye solution. I MB my lye solution (for the most part), and I heat my oils until clear. I often let the oils cool slightly, but they are always warmer than my lye solution and I have no issues. I use quite a bit of harder oils, fats, butters.
 

TheGecko

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I don’t find it to be true that your oils must be cooler than your lye solution. I MB my lye solution (for the most part), and I heat my oils until clear. I often let the oils cool slightly, but they are always warmer than my lye solution and I have no issues. I use quite a bit of harder oils, fats, butters.

Even before I started MBing my Lye Solution, it was always cooler than my Oils because I would make it the night before. Partly because my husband is sensitive to freshly made lye and partly because I didn't want to sit around waiting for my Solution to cool.
 

Zany_in_CO

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Is Lye temperature must be lower than Oils temperature? YES or NO?
Good question!!!
The REALITY is...it all depends on your recipe, your skill level and your average temp.
I agree with @TheGecko -- it all depends. You will learn this as you go along on your soaping journey. I have been soaping since 2003. For example:

For HP (Hot Process) the temp of the lye doesn't matter, although I mix the lye solution first and allow it to cool in the sink while melting my fats/oils/butters/wax in the crockpot. I stir the lye solution to make sure it is clear and fully dissolved before adding to the FAs (Fatty Acids).

For GM (Goat Milk) Soap CP (Colc Process), you want to "soap cool" to keep the batch from scorching due to the sugars present in goat milk. I made GM soap for 10 years for a wholesale customer. Since I didn't have fresh GM to work with, I used Meyenberg GM Powder -- added to the oils before adding the lye solution. I made my lye solution the night before. The next morning, I added fragrance, any other additives and the GM powder to the warmed oils. SB'ed (Stick Blended) for one full minute before adding the lye solution straight from the fridge.

For Castile Soap high in Olive Oil (or similar) I want both oils & lye solution 100 - 110°F (38°-44°C)

For Lard/Tallow/Palm CP (or similar) - 120°-135°F (52°-58°C)

For LS (Liquid Soap) CP - For best results and faster trace, combine when oils are 160°F and KOH solution is 140°F. Maintain 160°F while bringing to trace.

For GLS (Glycerin Liquid Soap) HP The ONLY time I use Carrie Petersen's GLS technique is in making 100% Olive Oil castile or bastile LS. 100% OO LS takes a long time to trace and to cook, so, and this is just me, I'm thrilled when it becomes soap in all of 2 minutes! CAUTION: For experienced LS'ers only! Due to the high heat of the KOH solution (over 210°F / 99°C) and possible exposure to toxic fumes if the KOH gets overheated (if it's yellow, it's scorched. Toss it.) TIP: Be sure to remove the melted KOH from heat the second you see "heat waves" rising from the surface to prevent scorching.
 

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