Quantcast

Do mixed oils separate as they cool?

SoapMakingForum

Help Support SoapMakingForum:

Joined
Oct 31, 2014
Messages
9
Reaction score
1
Bear with me here, this may be an odd one...

I premix several batches worth of my soapmaking oils in a 10 gallon pail. I am careful to mix the bucket thoroughly before pulling any oil out of it to use. Now that it's getting cooler in my soap kitchen, the bucket of oils is solid. My question is this - assuming the oils start out warm and well mixed when I initially make up my superbatch, will they still be well mixed several days later when cold and I want to make soap? Do the oils with higher melting points settle out? I'm worried that if I just pull the oils off the top of the bucket I might not be getting the right proportions.
 

new12soap

Well-Known Member
Joined
Apr 13, 2012
Messages
1,671
Reaction score
959
Just a random guess, but I don't think the melting point of the oils will cause them to separate.

The only potential problem I see is that if you used palm in your masterbatch, the stearic acid contained in it simply will not behave and likes to settle to the bottom. It does this on its own, too, it isn't just a case of not playing well with others.

Is there any way to separate out your batches after you mix the master? Mix all your oils in a large quantity, then split up the masterbatch into 3 or 4 or however many separate containers right then, and grab one when you are ready to go? That only works if you know your batch size ahead of time, of course.
 

boyago

Well-Known Member
Joined
Sep 11, 2013
Messages
1,031
Reaction score
834
Location
Portland, OR
yeah they will, not supper cleanly but enough to mess up your mix if you pull from the top. Whenever you pull from your master batch into smaller amount you want to heat and mix the master batch so ensure even distribution. But if you heat up the big MB and you make the same volume each time you soap then you can just do it once by dividing that batch into the smaller units that you use.
 

DeeAnna

Well-Known Member
Joined
Feb 20, 2013
Messages
13,349
Reaction score
18,957
Location
Northeast Iowa, USA
"...Do the oils with higher melting points settle out?..."

Yes, they can and do, depending on the temperature. Palm and rice bran oil are good examples of fats that will settle out at room temperature. You can see similar behavior in olive if you put room temperature olive in the fridge and watch it as it cools down.

Higher molecular weight saturated fats (fats high in stearic acid being the prime example -- lard, tallow, palm) will crystallize at the warmest temperatures, followed by the lower weight saturated fats (coconut, babassu, PKO). Unsaturated fats remain liquid at even colder temps. The more double bonds there are in a fat, the lower the temp has to be before the fat will solidify.

"...the stearic acid contained in it simply will not behave and likes to settle to the bottom..."

This behavior of palm oil is a perfect example of what's called "differential crystallization" to throw a $50 engineering term at y'all. :) It's not actually stearic acid as plain stearic acid, by the way. What settles out in palm is the high-stearic fat. It crystallizes first and settles out while the high oleic fats in palm remain liquid.

This is how "olein" and "stearin" were created when candle making was a big industry. High stearic fats like tallow and palm (depending on availabililty) were melted then slowly cooled. When the high-stearic fats crystallized out, they were separated from the liquid high-oleic fats by filtering or settling. The high-stearic fats -- the stearin -- was used for candle making. The high-oleic fats -- the olein -- were a glut on the market, and soapmakers were able to buy this olein cheaply for soapmaking.

Olein and stearin are still made today, although obviously it's not so much for the candle making industry any more.
 
Last edited:
Top