Why the brittle edges?

[ozziesgirl]

I made a batch of soap that I’ve made successfully several times, but this time I wanted to keep if from gelling, so I set it on my front porch immediately after putting it in the molds. It was 33 degrees and damp out. I was using Pringles cans for molds, which I also frequently do.
When I cut the soap today, the outer edges are brittle. The center of the bars seem normal, but the outer 1/4” is extra white and crumbly.
I also noticed that there was moisture between the cardboard and that plastic-ish inner coating of the Pringles can, which has never been the case before. Any thoughts on what has happened?
Here’s the recipe:
30 oz. olive oil
15 oz. coconut oil
5 oz. almond oil
7.14 oz. lye
17 oz. water

 

[soapmaker]

Have you ever sat it on the porch before? My thought is that it didn't warm up enough around the edges. That's why the center was good. Too cool for too long can cause crumbling as I found out with one of my batches. I had used td and wanted to avoid "crackle" effect. It did avoid that but the edges were crumbly and white. Temperature related I think.

 

[ozziesgirl]

Then I’m really confused. I read a bunch of posts about avoiding gel phase, and a lot of people said they stick their soap straight in the freezer. Why aren’t theirs doing this?
I used to just make soap and not worry about gel/no gel. Now that I’m trying to make a more consistent product, I’m either getting the volcano effect, or now this.

 

[Obsidian]

Was it hard and brittle or soft and crumbly? Soap that hasn't gelled needs more time in the mold. After bring it back to room temp, leave it in the mold for another 24 hours or so.
The moisture around the soap is from high humidity. I wouldn't put it outside if its damp out, use the fridge instead.

 

[soapmaker]

I've often wondered how long they leave it in the freezer. We have an unheated room (40 or 50 deg.) and I will allow my soap to start to warm up a little before I put it in that room. Then I watch it. I don't really go by the clock, just watch it for a few hours and bring it back inside without letting it get completely cold. And then, yes, like Obsidian said, let it in the mold longer.

 

[ozziesgirl]

I left it on the porch for about 4 hours, then cut it 2 and half days later. (3:00 pm Saturday - 9:00am Tuesday) The outer edge seems brittle and crumbly. Little hunks flake off as I cut it.

 

[Obsidian]

Hmm, it possible that you waited too log to cut then. Hard brittle edges usually mean you waited too long while soft crumbly edges means you didn't wait long enough.

Personally, I don't like the texture of soap that has been froze to prevent gel. It seems chalky and weird, I'd rather try to prevent gel by soaping cool and not using wooden molds. A fan in a cool room can help too. This really only work for recipes that don't get hot though, added sugar or honey might not work so well.

I tend not to use ingredients that increase heat. Goat milk is about the only one I'll use anymore and it doesn't overheat for me. If I want a boost to lather, I'll use aloe juice. I find it better than milk or added sugar and it doesn't cause overheating and no bad smell when mixed with lye.

 

[soapmaker]

I was using a pvc pipe to mold round soap. Not every bar crumbled at the edges, only the top and bottom. That's why I thought it was temperature related. Also I had this happen in a log mold when it didn't heat up enough. Even though you don't want it to gel, it still needs to get warm. In the log mold, every bar crumbled a bit and were white at the edges.

 

[soapmaker]

I guess we all have different experiences with different ingredients. Mine in the pvc mold was cut in about 20 hours, the log mold would have been between 16-18 hours and it was dry and crumbly on the edges.

 

[scard]

I've had those brittle edges on some of the test soaps I made in the plastic milky way molds. I thought it was because I had stirred in the FO so the soap would stay fluid enough to prevent air bubbles trapped in the detail of the mold. But I also put a bit of sugar in. Sounds like it may have been more of a temperature issue?

 

[soapmaker]

Yes, small test molds, less heat.

 

[IrishLass]

The center of the bars seem normal, but the outer 1/4” is extra white and crumbly.

The terms 'extra white' and 'crumbly' sure seem to describe the symptoms that the surface my soap comes down with whenever I've purposely set out to prevent it from gelling. The white surface on mine is always ash (the typical chemical reaction of partially saponified soap hitting the open air), and the crumbliness stems from the soap not being fully saponified yet. Mine is always a soft flakiness/crumbliness, though (like feta cheese), not a hard brittleness (like cold cocoa butter).


IrishLass

 

[Steve85569]

I have had the problem when using too many salty additives. Sodium acetate , sodium citrate and a pinch of table salt will give me salts migrating out of the soap resulting in hard sometimes crumbly edges.

The problem with trying to diagnose someone else's soaping problems is that there are so many variables.

 

[soapmaker]

The terms 'extra white' and 'crumbly' sure seem to describe the symptoms that the surface my soap comes down with whenever I've purposely set out to prevent it from gelling. The white surface on mine is always ash (the typical chemical reaction of partially saponified soap hitting the open air), and the crumbliness stems from the soap not being fully saponified yet. Mine is always a soft flakiness/crumbliness, though (like feta cheese), not a hard brittleness (like cold cocoa butter).


IrishLass

Yes, I like your descriptions of feta cheese and cocoa butter. Definitely not like cocoa butter. More towards the feta cheese crumbliness. Like Steve said it is hard to diagnose someones soap because of all the variables. For me keeping it warmer without allowing gel fixed the problem.

 

[GoBlue]

Thank you, everyone! This is very helpful. I make soap in our cold garage and have been having this problem for a while. Now I know that after pouring into molds, I need to put the soap in a preheated oven and keep it warm for a while.