Does mold shape or size affect outcome?

[Mobjack Bay]

To date I’ve made soap in a small silicone loaf mold, a small slab mold (wood lined with parchment), lined cardboard boxes (parchment), three different kinds of silicone bar molds that hold six or more individual bars with rectangular, oval, or round shapes. I have produced soap that makes me happy using the loaf, slab and rectangular bar molds, but can’t seem to produce a truly satisfactory oval or round bar. The problems have ranged from lots of ash to uneven gelling to the last batch where the soap was kind of crumbly or granular looking after 24 hours. The oval molds are the pink ones that are all over Amazon. The silicone is pretty thin and I would suspect the material except that my rectangular bar molds are made from the same. I just recently made matcha tea soap in the rectangular bar mold and the soap looks wonderful. I used the round bar mold once. The silicone it’s made from is stiffer and a somewhat translucent blue.

I usually use 33% lye and soap on the cooler side. My recipes have varied, but the most recent crumbly batch was a vegan soap with 50% palm that has worked perfectly more than once in the loaf mold.
Is there something about using oval and round bar molds that I should know, or is it just me?
I have not tried mixing a 3 lb batch to split between the 2lb loaf mold and the individual oval molds, but I guess I could try that as an experiment.

 

[dibbles]

For me the problem with individual molds is getting the soap to gel. And it also seems that if the soap doesn't gel in the individual molds the ash is much worse. I put my individual cavity molds on a heating pad and insulate well, even in the summer.

I don't really see a difference in the rectangle vs round molds that I have.

 

[shunt2011]

I agree with dibbled. I don’t make much soap in individual molds. The rare occasion I do I cover with plastic wrap after spraying liberally with alcohol then cover with a dish towel and place on a cookie sheet in a warm oven. I then keep it covered for a day or two before taking out of the mold then spray again and cover in a raspberry flat.

I prefer silicone loaf molds.

 

[earlene]

When I use individual molds, I often use them just for overflow & they go in the oven for CPOP with the larger mold at the same time. So they do gel.

But sometimes, I use molds that I don't put into the oven and then they don't gel. Sometimes they get more ash, sometimes they don't. I believe that is recipe based.

I have noticed no difference between round and oval soaps, however. But I only have one oval mold and it is a hard plastic, and no round silicone molds. My only round molds are for round loaves; one is plastic (re-purposed round plastic kitchen container) and the other(s) have been re-purposed Pringles containers. The round soaps always gel with CPOP or on their own.

 

[Mobjack Bay]

In my attempts to get super smooth tops on the oval bars, I have been pouring at what I thought was a stable emulsion. But maybe it isn’t stable? I ran across this thread today and now I’m wondering if under-blending could be contributing to my problems. The last bad batch ended up granular on top, but normal looking below. Could that happen as a result of a less than fully stable emulsion? I have not seen any oil floating on the top of the bars.

 

[Mobjack Bay]

I posted the weirdest of my oval mold issues in the Beginners Forum, here, with the hopes that those with experience can help diagnose the problem(s). I’m convincing myself that many problems to date could be due to only reaching a barely stable emulsion stage.

I pretty much put the oval soaps below into the fail category, because they were covered in ash, but they look better after a little cleaning. I also polished them with a nylon stocking, which worked nicely. I cleaned up the edges with the back edge of my paring knife, which works much better for me than trying to use a vegetable peeler. I drag it along the edge rather then trying to cut the soap. I was testimg FOs and colors at the same time . With the ash coating, the colors were way too pale for my liking so I changed course and added more indigo powder and some AC to the batter for the rectangular bars. I don’t think the ovals bars are ever gelling for me but the rectangular bars might be. I keep wondering if I should try a low temp CPOP with the oval bars. Given the way the cavities are configured for the oval bar molds (there’s relatively more space between them at the ends due to being oval...) and the fact that the volume is smaller for the ovals molds (3 oz.) compared with the rectangular cavity molds (4 oz.) I think the bars could be cooling more quickly.

This first soap is lard 60%, HO safflower oil 20%, CO 15% and castor 5%. The colorant is madder (very weak dye) and the FO is MMS Osmanthus @ 1 TBS ppo, which I like. In fact, I like every FO I purchased from MMS. Not one of them smells like chemicals or cologne. I made the inverted stamp really quickly with some wire I had nearby. You can see the color the soap might have been if it had not ended up covered with ash. I think the stamp worked well for my first try:

The oval soap below is the same recipe as above with avocado oil subbed for the safflower. The FO is Jacob from MMS. The rectangular soap is a vegan palm (50%) recipe with OO (30%), CO (15%), and castor (5%). I added indigo powder, kaolin clay (which got clumpy for some reason) and AC, all dispersed in oil. The soap turned grey on the outside (easier to,see in the second photo) but is a nice dark navy on the inside, which you can see on the trimmed edges. It seems a little strange (or lucky) that I didn’t have any problems with ash when using the rectangular molds for this batch or for the Matcha tea lard recipe batch that I posted in it’s own thread.

 

[Mobjack Bay]

I re-read some of the earlier posts here and finally noticed that others are CPOP’ing individual molds or putting them on a heating pad. That’s also what KiwiSoap is doing with their tests runs, so I will definitely give it a try.