Soap heaves and heats up while in the mold

[Jaaret]

I have a mystery. I made a batch of soap today. After pouring it into the molds and set it aside to cure, the soap got hotter and heaved up in the mold until it cracked. This happened once before. The main common denominator was that I added ground oatmeal to both batches, about 2-3 tablespoons for the whole 72 oz batch (weight of oils only)




Here are the facts:
21.6 oz. Coconut oil (30%)
21.6 oz. Palm oil (30%)
7.2 oz. Cocoa Butter (10%)
7.2 oz. Almond oil (10%)
7.2 oz. Olive oil (10%)
3.6 oz. Jojoba oil (5%)
3.6 oz. Bees wax (5%)

9.6 oz. Lye (8% discount applied)
22.5 oz. Water (The lye is a 40% solution)

My hunch is that the oatmeal, added at trace, is absorbing some of the water and making the lye solution more concentrated and speeding up the saponification. That might explain why the batches get hotter in the mold and heave up.

The last batch that did this got so hot that it went from opaque to semi-transparent. It eventually cooled back down and became opaque again. I'm using the soap now and it's fine. I'm just trying to figure out if it is the ground oatmeal that is causing this reaction.

 

[carebear]

could very well be - try making your lye solution at 35%.

sugar can also contribute to this (from honey or milk).

tubular molds get HOT, hotter than logs even.

 

[NMAriel]

Hi, don't know if this helps. I've made oatmeal soap a long time ago, and I took plain oatmeal and finely ground it. It did gel, but it did not crack like yours though. How do you use the oatmeal, whole or ground? Could that be part of it?

 

[heartsong]

x

did you use any f/o that could heat up?

some here refridgerate the soap after pouring in mold-i wonder if it would stop that? do you have a place to "chill-out" but not freeze?

 

[Jaaret]

Oatmeal

I used finely ground oatmeal that I sifted through a fine mesh strainer.

The last batch that did this, the one that became became a semi-transparent gel for a brief time, had both oatmeal and honey. So it could be a combination of factors: the tubular mold, the oatmeal absorbing some of the water in the lye solution, and the sugar in the honey (in the previous batch). The next time I use oatmeal I'm going to make the lye a weaker solution.

 

[Lindy]

Hey Jaaret,

The only time that happened to me it was when I was attempting my transparent soap and you make it very lye heavy then rebatch so on the first part it was quite dry and heaved liked that. It was also harder than a rock but it rebatched nicely. Never did turn into transparent soap, but that's my fault ...... :wink:

Cheers
Lindy

 

[carebear]

happens to me when I use my PVC pipe molds. but only the top one is messed up so I don't really care.

 

[mandolyn]

happens to me when I use my PVC pipe molds. but only the top one is messed up so I don't really care.

Ditto here. I have to watch my molds like a hawk, then as soon as I see any bulging at all, I either put in into the fridge or some cool place so it won't crack. I've had good luck doing that. By the time it starts the bulging, it's at full gel, so I don't get bulls eyes.

It doesn't hurt the soap at all as you found out.

Beeswax + honey + pvc = a hot combination. I doubt very much that the oatmeal is the culprit unless it has sugar added to it.

 

[jbruner7]

I agree

I agree with the honey and milk. Any time you use milk it heats up more and honey also. Plus never cover up or wrap soap made with either of these as it will bubble up and even come out of the molds. Trust me I found out the hard way. It is not the oatmeal that is causing this to happen. It is the mold you are using plus the honey plus the milk. all batches of gm soap i make gets pretty hot and adding honey to it well it gets even hotter.

Just do as they said above. watch it and stick it in a cool place when you see it acting up and it should be fine.

Good luck to you and Merry Christmas and Happy Holidays!

 

[mandolyn]

happens to me when I use my PVC pipe molds. but only the top one is messed up so I don't really care.

Ditto here. I have to watch my molds like a hawk, then as soon as I see any bulging at all, I either put in into the fridge or some cool place so it won't crack. I've had good luck doing that. By the time it starts the bulging, it's at full gel, so I don't get bulls eyes.

It doesn't hurt the soap at all as you found out.

Beeswax + honey + pvc = a hot combination. I doubt very much that the oatmeal is the culprit unless it has sugar added to it.

Oops, looking at the pic again, I see cardboard not pvc, so eliminate that factor.

 

[topcat]

Hi Jaaret, did this batch have honey? If not, it could just be the shape of your mould. I have had a milk carton mould overheat (warm day and yoghurt added at trace) and I have concluded that the concentration of the batter in a narrow, tall mould could contribute to this. I have soaped fruit (so, sugar) and milk before and used both a log mould and a square tray mould and neither overheated on me those times.

Tanya

 

[Bunny]

I never could make honey, milk or beeswax soaps in upright PVC molds. They'd overheat every time. Upright molds do not dissipate heat well at all. You should try those recipes in a horizontal log or slab mold... they have more surface area which dissipates the heat much faster, so it doesn't build up and cook your soap. I finally threw my PVC pipe molds away because of that. A friend of mine made me some wood log molds years ago out of some scrap wood and I love those things! They just can't be beat for soapmaking. I can use them for slab molds or log molds. I've been using those old things for probably ten years now.

 

[Jaaret]

Milk and Honey

Hmmm... I didn't use honey or any dairy product in the last batch. My new theory is that it's the beeswax, the shape of the mold and the temperature I start out with. I mixed the lye with the oil when they were both around 120 degrees. I think if I start with temperatures around 90 degrees and perhaps cover the molds and put them out on the back porch to cool will prevent them from overheating and heaving in the molds.

Thank you for all the insights into this phenomenon. I've learned a lot!

 

[mandolyn]

Re: Milk and Honey

Hmmm... I didn't use honey or any dairy product in the last batch. My new theory is that it's the beeswax, the shape of the mold and the temperature I start out with. I mixed the lye with the oil when they were both around 120 degrees. I think if I start with temperatures around 90 degrees and perhaps cover the molds and put them out on the back porch to cool will prevent them from overheating and heaving in the molds.

Thank you for all the insights into this phenomenon. I've learned a lot!

You're welcome Jarat. Sometimes just having a fan blowing on the mold will keep the temp down, & yes mixing at lower temps helps. Have you considered soaping at room temp? I have far less overheating since I started soaping at room temp.

 

[Bunny]

Yes, beeswax, that's right up there with honey.