Melting point of mixture?

SoapMakingForum

Help Support SoapMakingForum:

tinycyclops

Active Member
Joined
Nov 22, 2014
Messages
39
Reaction score
21
Location
Utah
Kind of crazy question, so forgive me if this is silly. Chemistry is not my strong suit, it took me an embarrassingly long time to pass organic chemistry. However, I do remember talking about mixtures, and how they can change the physical properties (melting point, boiling point, etc) of a pure substance.

How does this apply to soapmaking you ask? Maybe it doesn't but, I'm going to be using my first potentially accelerating fragrance oil this weekend, and I know the conventional wisdom says to soap at lower temps. Right now, I soap at around 100 degrees because I have cocoa butter in my recipe. What I'm wondering is if I'll even be able to let my oils cool down to around 80 degrees, or will the cocoa butter resolidify? Does the mixture of oils affect the melting point?

Recipe, fragrance and additives for reference:

33% Olive Oil
25% Coconut Oil
15% Rice Bran Oil
12% Avocado Oil
10% Cocoa Butter
5% Castor Oil

6% Superfat
30% Lye concentration
Additives: coconut milk powder, kaolin clay, silk

Fragrance is Fresh Cut Roses from NG

Sorry if this is a silly question. And thank you!
 

KristaY

Supporting Member
Joined
Mar 2, 2014
Messages
2,577
Reaction score
1,958
Location
Arizona, USA
This absolutely isn't a silly question! I'm not a room temp soaper because I use palm oil and butters in most of my recipes and don't want to chance getting a false trace. Do you plan to do any multi color designs? That will play a part in how to proceed. If I'm going to use NG's Fresh Cut Roses, I know it's a moderate accelerator so I either plan a single color or a gradient pour where I add the FO to each color right before I pour it.

If I'm doing a single color I add the color to the oils before the lye, SB the color in. Add the lye and bring to emulsification. Then I slowly add the FO, whisk by hand, and pour at medium trace. You can also hold out an oz or so of the OO from the recipe, warm it to about 100*, add the FO to that, then add that mixture to the batter. It will help slow things down by having the FO warmed and diluted.

The other trick I use for speedy FO's is to do a gradient pour. Once your batter is at emulsification, divide it into containers for color & scent. Also divide your FO into portions for each color. Add the color to the first portion and mix well by hand. Slowly add the FO, mixing by hand and pour once incorporated. Mix the second portion in the same way. By the time you're ready to pour the 2nd, the 1st should be firm enough to support the next layer. Continue on until all portions are mixed and poured.

I hope this helps & isn't too confusing!
 
Last edited:

DeeAnna

Well-Known Member
Joined
Feb 20, 2013
Messages
13,469
Reaction score
19,368
Location
USA
Having soaped with NG Fresh Cut Roses about half-dozen times, yes, it does speed things up, but it's not acted nasty horrible for me. I really don't like scents that act up, and I'm quite willing to use this FO.

Here's what I would do in your shoes:

Pick a simple swirl for your first time if you want to do anything decorative. I'd suggest an in-the-pot swirl or other design that is easy and fairly quick to do.

Warm your fats so you know your cocoa butter is fully melted, but try to not go any warmer than needed. I've found with my high-lard recipes that if I don't get the lard melted completely until it is transparent, I get stearic spots in my soap. So I get my fats melted to about 110 deg F or pleasantly warm to the touch.

Let your lye solution cool until just warmish like the oils. You don't need to obsess over matching the lye and oil temps like the beginner books say, but don't use it smokin' hot either.

Set the FO aside in a place where you won't leave it out -- I put it in my mold so it's impossible to ignore it.

Put the lye solution and additives (however you normally do this) into the oils. Lightly pulse your stick blender a few times, interspersing with hand stirring, to gently bring the soap batter just to a stable emulsification -- you want to stop when the oils and lye are mixed and not separating from each other, but before obvious sign of trace.

If you're going to separate portions for coloring and swirling, do it at this point.

Right before you want to pour the soap into the mold, put the FO into the batter. If swirling, divide the FO amongst the various portions of batter. Hand stir until the FO appears blended in well. Stir gently more like you're folding in egg white into a cake, rather than whipping it good. :)

Finish swirling your soap and/or get it into the mold.

Hope this helps!
 
Last edited:

tinycyclops

Active Member
Joined
Nov 22, 2014
Messages
39
Reaction score
21
Location
Utah
Thank you both for such thorough responses!

My plan for this batch is to make the bottom third one solid color, and the top two-thirds either an in the pot swirl or drop swirl. I already was planning on waiting to add the fragrance until colors had been mixed. So this seems like it still might be a good plan, but I'll have a back up just in case.

This really helps so much. Thank you again!
 

DeeAnna

Well-Known Member
Joined
Feb 20, 2013
Messages
13,469
Reaction score
19,368
Location
USA
To answer your question about the fat mixture -- I realized you haven't gotten an answer to that one! You're thinking about boiling point elevation and freezing point depression of a mixture vs. a pure liquid.

I soap with a high % of lard, so any freeze point depression created by my others fats is going to be small, and it's not worth giving it much thought.

With a mixture of mostly liquid oils like your 10% cocoa butter mixture, freeze point depression might be something you can take advantage of. Best way to figure this out is to melt the mixture, let it cool, and occasionally measure the temp. When the temp is low enough that the cocoa butter begins to cloud the mixture, you've got your answer!
 

tinycyclops

Active Member
Joined
Nov 22, 2014
Messages
39
Reaction score
21
Location
Utah
Yes, that's what I was referring too! I'll have to test that one day when I have some extra time.
 

tinycyclops

Active Member
Joined
Nov 22, 2014
Messages
39
Reaction score
21
Location
Utah
I just wanted to come back and say thank you all so much for the advice! I made my soap yesterday and it went awesome. It did accelerate a bit, but it was totally workable in my design (actually it was perfect, the bottom layer was completely set when I added my top layer). I'm just waiting to unmold now. So thank you again!
 

cmzaha

Supporting Member
Joined
Sep 19, 2011
Messages
11,914
Reaction score
11,492
Location
Southern California
I just wanted to come back and say thank you all so much for the advice! I made my soap yesterday and it went awesome. It did accelerate a bit, but it was totally workable in my design (actually it was perfect, the bottom layer was completely set when I added my top layer). I'm just waiting to unmold now. So thank you again!
I love it when a plan comes together. Accelerating fo's can be used to make clean layers by just adding the fo to the layers as you are ready to pour them
 

Latest posts

Top