Soap's bubbling on the underside?

[Izzye]

This is the first time I've ever made soap so I'm not entirely sure what's going on here. The recipe was 150g olive oil (pomace if that makes a difference), 50g coconut oil, 28g lye, 66g water, a bit of green dye and a superfat level of 3%.

It was left in the pantry over the weekend and then turned out and put in the airing cupboard a couple of days ago but I couldn't resist having a look at it and when I turned it over it had this weird bubbling on the bottom.

What have I done wrong? Or was it just a bad combination?

 

[lionprincess00]

Did you use a silicone mold? Cpop it? Heating pad under it? Can you give any details about the process you used from start to finish? It would help us better identify the cause.

 

[Izzye]

It was in a silicone mould, no heating pad, didn't cpop it (had to google that one).

I made it in the kitchen with the back door open (I got scared of the lye fumes), guestimated when the lye got down to 50 degrees as I had no thermometer, mixed everything together with a silicone spatula and then with a stick blender, added in some green colouring, mixed a bit more to what I hoped was medium trace but I think I was a bit over, and transferred into a jug and then the mould. The temperature in the pantry has a tendency to fluctuate through the day and depending on the weather, I don't think it got too hot in there as the heating was down to 12 as neither of us were in the house and it wasn't particularly sunny. I moved it from the moulds about four days later to a large cupboard we rarely use.

 

[dibbles]

Is the side you show in the picture the part that was on the bottom of the mold? If so, when you unmolded the soap did you notice any bits left behind? It looks like what I see when I get impatient and unmold when the soap is still a little too soft and parts stick to the silicone. I'm not sure about the little holes - maybe just air bubbles?

 

[toxikon]

Apparently, this kind of thing can happen when you use a silicone mold and the soap heats up too much during the gel phase. The bottom of the soap gets so hot that it basically boils - and with no air circulation because of the silicone, it creates those little holes and pock marks.

What kind of colorant did you use? Is it one that's safe and tested for cold-process soapmaking?

 

[Izzye]

Yes, that's the side at the bottom of the mould. There was nothing left on the bottom when I took them out of the moulds and I'm pretty sure it was smooth when I did so. I wouldn't be surprised if there were soap bubbles in it, I didn't have quite enough mix to cover the blender all the time, but surely they would rise to the top rather than sink to the bottom?

 

[shunt2011]

It looks to me like it may have been a bit soft when unmolded and just stuck to the bottom some. Just a guess, as I've had some come out that way when I didn't wait long enough to unmold. Have you zap tested it? If no zap you should be fine.

 

[Izzye]

Apparently, this kind of thing can happen when you use a silicone mold and the soap heats up too much during the gel phase. The bottom of the soap gets so hot that it basically boils - and with no air circulation because of the silicone, it creates those little holes and pock marks.

What kind of colorant did you use? Is it one that's safe and tested for cold-process soapmaking?

I used a concentrated green waterbased cosmetic dye which unfortunately, doesn't say whether or not it's suitable for cold process. If I put a USB fan cooler like you'd use for a laptop underneith the mould would that stop it overheating?

 

[kchaystack]

I used a concentrated green waterbased cosmetic dye which unfortunately, doesn't say whether or not it's suitable for cold process. If I put a USB fan cooler like you'd use for a laptop underneith the mould would that stop it overheating?

You could try that, or you could use less water. that would make it less likely to gel. But that might mean it would take longer to unmould.

It might also just be air bubbles. you said that it got pretty thick. If you didn't burp your stick blender, sometimes it happens. To prevent this you just need to use the SB less.

If it does not zap your tongue, then it should be fine to use, after a cure of 4-6 weeks. If nothing else you can use a vegie peeler and plane off the offending area if it just bugs you, tho it also would smooth out after a couple of uses.

 

[Izzye]

You could try that, or you could use less water. that would make it less likely to gel. But that might mean it would take longer to unmould.

It might also just be air bubbles. you said that it got pretty thick. If you didn't burp your stick blender, sometimes it happens. To prevent this you just need to use the SB less.

If it does not zap your tongue, then it should be fine to use, after a cure of 4-6 weeks. If nothing else you can use a vegie peeler and plane off the offending area if it just bugs you, tho it also would smooth out after a couple of uses.

I read somewhere about putting it in the fridge once it's in the mould? Would that stop it gelling? How do I know what is a safe amount of water to add? I've been using the brambleberry lye calculator which doesn't give a tolerance, just an amount.

No zap, doesn't really taste good either. I can't believe I voluntarily just licked soap. I'll make a bigger batch next time and try and get less air in it.

 

[IrishLass]

Welcome Izzye! :wave:

I just noticed that according to the gram weights you posted, the total weight of your oils was only 200g or 7oz, which amongst soap-makers is a very small batch indeed, and I just wanted to verify what type of scale you used. The reason being is because when it comes to weighing lye- size definitely matters (batch size, that is). To explain- the lower the amount of lye being weighed, the exponentially greater that any tiny discrepancy in weight can cause potential problems in ones' batch, even if your lye weight is off by just a fraction of a gram. For what it's worth, the smallest batches I ever make are 227g/8oz.(oil weight), but only with my very precise scale that weighs accurately down to .01g. When using my other scale, which only weighs accurately down to 1 g, the smallest size batches I attempt to make with it are 500g (oil weight).


IrishLass

 

[toxikon]

I read somewhere about putting it in the fridge once it's in the mould? Would that stop it gelling? How do I know what is a safe amount of water to add? I've been using the brambleberry lye calculator which doesn't give a tolerance, just an amount.

No zap, doesn't really taste good either. I can't believe I voluntarily just licked soap. I'll make a bigger batch next time and try and get less air in it.

Yes, popping it into the fridge or freezer will prevent gelling.

I'd recommend switching over to SoapCalc or Soapee calculator for more control over your recipes. The standard water/lye amount for most calculators is 38% Water as % of Oils, which can be a little high for most soapmakers.

It's also good to get into the habit of using "Lye Concentration" or "Lye to Water Ratio" instead of the default. It gives you more control and better results.

The standard 38% Water as % of Oils works out to approximately a 25% Lye Concentration. Most soapers prefer working with less water and a higher lye concentration - around 30-35% is great. For pure Castille soap, which is very slow to trace and cure, an even higher Lye Concentration of between 40-45% works well. 50% is the max you can go because some of the lye will not dissolve any higher. But for most standard recipes, 33% Lye Concentration is a good sweet spot.

 

[dibbles]

Apparently, this kind of thing can happen when you use a silicone mold and the soap heats up too much during the gel phase. The bottom of the soap gets so hot that it basically boils - and with no air circulation because of the silicone, it creates those little holes and pock marks.

I have had soap that overheated in a silicone mold and created pock marks on the surface. The reason it looks to me like it was a bit too soft when unmolded rather than an overheating issue is that the edges are smooth. Could be either though.

Izzye, if your batter was very thick the air bubbles could well be trapped in the batter and not rise to the top - even if you banged the mold to release them. Been there, done that too.

And IrishLass has a very good point about batch size.

 

[kchaystack]

I read somewhere about putting it in the fridge once it's in the mould? Would that stop it gelling? How do I know what is a safe amount of water to add? I've been using the brambleberry lye calculator which doesn't give a tolerance, just an amount.

No zap, doesn't really taste good either. I can't believe I voluntarily just licked soap. I'll make a bigger batch next time and try and get less air in it.

Putting it in the fridge can prevent gel, however the real way to prevent it is to change your lye concentration. Personally, I like my soaps to gel - it means I can get them out of the moulds in less than 24 hours.

The Brambleberry calc is terrible. I use soapee.com. You can adjust your lye concentration in that tool pretty easily. The least amount of water you can use is a weight = to your alkali (NaOH or KOH). This is a 50% concentration - but I would not soap with that. I usually use a 33.3333% concentration, or twice the weight of water to lye.

Yes the smallest batch I would suggest is 500g.

 

[Izzye]

Welcome Izzye! :wave:

I just noticed that according to the gram weights you posted, the total weight of your oils was only 200g or 7oz, which amongst soap-makers is a very small batch indeed, and I just wanted to verify what type of scale you used. The reason being is because when it comes to weighing lye- size definitely matters (batch size, that is). To explain- the lower the amount of lye being weighed, the exponentially greater that any tiny discrepancy in weight can cause potential problems in ones' batch, even if your lye weight is off by just a fraction of a gram. For what it's worth, the smallest batches I ever make are 227g/8oz.(oil weight), but only with my very precise scale that weighs accurately down to .01g. When using my other scale, which only weighs accurately down to 1 g, the smallest size batches I attempt to make with it are 500g (oil weight).

IrishLass

I used my bath bomb scales which only go down to 1g so I was rounding up or down to the nearest gram, I don't think I realised just how scientific soap is; with bath bombs if a measurement is a few grams over I'll chuck it in anyway. The next one I was planning on doing is going to be just over 500g so hopefully that'll solve whatever problem I have here. I might need to buy some bigger bowls at this rate though.

 

[Izzye]

Putting it in the fridge can prevent gel, however the real way to prevent it is to change your lye concentration. Personally, I like my soaps to gel - it means I can get them out of the moulds in less than 24 hours.

The Brambleberry calc is terrible. I use soapee.com. You can adjust your lye concentration in that tool pretty easily. The least amount of water you can use is a weight = to your alkali (NaOH or KOH). This is a 50% concentration - but I would not soap with that. I usually use a 33.3333% concentration, or twice the weight of water to lye.

Yes the smallest batch I would suggest is 500g.

Soapee's one looks way better than the brambleberry one. Do however now have a question; what's the difference between 92, 76 and fractionated coconut oil? The stuff I was using just says coconut oil on the label.

 

[kchaystack]

Soapee's one looks way better than the brambleberry one. Do however now have a question; what's the difference between 92, 76 and fractionated coconut oil? The stuff I was using just says coconut oil on the label.

76 and 92 is the melting point in F. Fractionated CO has been chemically altered to remove some of the fatty acids. It is also a liquid.

More than likely if you got it in a shop it is 76 degree.

 

[Susie]

Yes, that's the side at the bottom of the mould. There was nothing left on the bottom when I took them out of the moulds and I'm pretty sure it was smooth when I did so. I wouldn't be surprised if there were soap bubbles in it, I didn't have quite enough mix to cover the blender all the time, but surely they would rise to the top rather than sink to the bottom?

I call this mold rash, it happens when you use a silicone mold, and your soap goes through gel. If you put it in the oven (CPOP), it will happen every place the soap touches the mold. It is perfectly harmless, and can be cut off it you are very particular about the appearance of your soap.

 

[Izzye]

76 and 92 is the melting point in F. Fractionated CO has been chemically altered to remove some of the fatty acids. It is also a liquid.

More than likely if you got it in a shop it is 76 degree.

I did wonder if it was a melting point, but then I thought I can melt it in my hands and there's no way I'm 76 celsius. Is one better than another? I'm not sure I've ever come across fractionated coconut before.

 

[navigator9]

For what it's worth,what I like to suggest to newbies is this, although it's not very popular, because it's always so appealing to want to try everything at once, but here goes...take a very simple recipe, three or four oils, no color, no fragrance. Make that recipe until you can do it successfully every time. Then change one thing, just one. Maybe add color or fragrance or try a different oil or butter. If you only change one thing at a time, you'll know that's what's responsible if something weird happens.

There has been a lot of discussion in this forum regarding bubbling and silicone molds. Some soapers get those bubbles or pock marks every time they soap in silicone, while others, like me, CPOP in silicone and have never had that happen. I hope someone is able to really nail down the cause of this some day. The good thing is, if your bubbles are "mold rash", it's purely cosmetic, so your soap is still fine. Best of luck with your next batch!