Question for those who use silicone loaf molds

[Carly B]

I'm new to soaping - I only have about 8 or 9 batches "under my belt," but I wanted to ask the experts here who use silicone loaf molds some questions.

I have the equivalent of a 1 lb square mold (it's really cute) and a 2 pound loaf mold. How long do you leave the soap in the mold? I have had mixed successes Since I'm learning, I'm trying all sorts of variables--using salt water or sodium lactate, changing the water:lye ratio, and of course, trying different oils.

I'm not finding a lot of consistency of results. Some have been hard and ready to remove from the mold within hours and came out cleanly. Some have felt hard on the top and the sides, but were basically soap dough at the bottom of the mold even when left overnight.

So I'm wondering how to know when to take it out of the mold. All the soaps came to trace fairly quickly and some were quite firm when putting them in the mold. I know the water can't evap through the sides of the mold. so I'm hoping if leave them in the mold longer, it will help. But I'd like some guidance on how long from
someone with a lot more experience than I have.

Thanks for any suggestions.

 

[jcandleattic]

I make 3lb batch molds, and make sure I gel, and can unmold at about 18 hours - if they go ungelled I have to wait 24-48 hours before I can unmold.

 

[lenarenee]

No two soaps will be the same.

You've done a good job learning the different things that affect soap hardness. Fragrances are another. Ex: Nurture's black raspberry vanilla in a tall and skinny mold took a week for me to unmold...and I should have waited even longer.

Forcing gel, or CPOP in the oven can help a lot- but there can still be some variances.

As for how I tell when to unmold; gentle press with a finger on top of soap, if it feels close to firm I'll squeeze the sides of the molds (about half way down the side) to see how much give it has. But ultimately - I purposely leave a mess on the edges of the mold! I use those to press with my finger, or if there's enough leftover batter...put in an individual mold and use that as a test. When in doubt, I leave a day longer.

 

[KiwiMoose]

I usually wait 24 hours ( for a 1000g mold) - sometimes the corners get a little squished when unmolding, but only by half a centimetre or so.

I gel my loaf mold, and use sodium lactate.

 

[runnerchicki]

I have that same mold (two of them actually). I can usually unmold in 24-36 hours if the soap gels. I have a wood support box that I put my silicone molds in to keep them from bowing and it helps retain the heat. I put a cardboard box over it and cover that with a blanket. Before I used the wood box, I usually had to wait 48 hours or more before I could unmold without the sides tearing from sticking. I don't use SL very often lately ... because I keep forgetting to put it in lol.

I think the small batches in silicone lose heat fast, so I really pay attention to insulating them. I have done CPOP before, but 1) I'm using a lot of lard and tallow lately and do not want to risk overheating and bringing out a smell, and 2) I live in Arizona and I avoid using my oven at all costs while the weather is still so warm. The wood box covered with a blanketed cardboard box really retains a lot of heat.

 

[Anstarx]

Different oils will lead to different results. With additives there are just too many possibilities.
I have soaps with lots of hard oils that was mashed potato consistency when in mold that sticky and soft after a week in hot weather, and I have watery castiles soap hard as rocks only 24 hours after chilling in the fridge. I had to cut the castile with a hacking saw lol. It was caused by accidentally spilling too much sodium lactate.)

There are some determined rules, like 70% CO or higher need to unmold and cut within 4 hours and high OO will need at least a week or so.

However, I'd say best way for a beginner (like myself) to get a sense of drying time is to pick a balanced recipe (a blend of soft and hard oils) you like and first make it in a small batch (like a pound) without any way to increase hardening speed (salt, sodium lactate, gelling, cpop, etc.) and test it every 12 hours or so. Say it take 3 days for your soap to be hard enough to cut, then you will know if you used salt/gelling/ larger batch...it will take less than that, and if you use more soft oils it will be longer than that.

I don't usually gel my soap and prefer to prevent gel by keeping them in the fridge. Usually I will first squeeze the mold lightly to see if the mold will dent. If not, I'll scratch the surface lightly with a knife (pick somewhere your don't mind scratching of course, like the ends that will be cut off). If it feels like cutting into room temp butter then it's not ready. If it's feels like cutting fridge butter then it's ok to cut for me.

It also helps that you keep some leftover soap batter in a small mold in the same environment (fridge, oven, heat blanket...etc.). Smaller batches hardens slower so it that turns solid enough to be cut like room temp butter then the main batch is probably ready.

 

[shunt2011]

Different oil combinations will vary greatly on how long it takes to get out of the mold. I make 6 lb batches in a silicone mold with a wood box. My soaps can be unmolded in 18 hours for my most used recipes. My salt soap has to be cut at 3-4 hours. My mostly liquid oil soap takes about 24 hours. I always use sodium lactate or salt. I also always gel my soap.

I also generally use a 30-33% lye concentration. More liquid will make it harder to unmold as well.

You will learn how your particular recipes perform after some time.

 

[jcandleattic]

Less liquid will make it harder to unmold as well.

?? I find the opposite is true. The more liquid, the harder it is to unmold, the longer I have to leave it sit. That's the main reason I switched from 28% lye concentration to a 33-35% concentration.

 

[TheGecko]

Not an expert by any means as I am in my first year of soaping, but logic says you won't find any consistency if every batch is different. I did the same thing (same size molds too)...made a dozen or so different batches of soap with different oils, different butters, different ratios and then forced myself to stop making soap for a month so I could look at what was coming out of my curing rack. Then I picked ONE recipe after reviewing my notes and testing my soaps, and then made several batches to see if I was getting consistent results.

Of course, not every batch is going to be exactly the same unless you are a robot in a climate controlled environment and even then, there is no guarantee unless you have complete control over your ingredients. I've been fairly consistent until the last two weeks...our weather is changing; it's getting cooler and it's raining. Hubby is looking at building me an insulated box in the garage with a small computer fan to circulate the air inside. I also just ordered a case of dehumidifying packs from the Dollar Store as we sometimes get condensation on the inside of our vehicle windows and those should work for my box.

 

[shunt2011]

?? I find the opposite is true. The more liquid, the harder it is to unmold, the longer I have to leave it sit. That's the main reason I switched from 28% lye concentration to a 33-35% concentration.

You are correct. I meant it that way. I meant more. Sorry. Fixed it.

 

[penelopejane]

Not an expert by any means as I am in my first year of soaping, but logic says you won't find any consistency if every batch is different. I did the same thing (same size molds too)...made a dozen or so different batches of soap with different oils, different butters, different ratios and then forced myself to stop making soap for a month so I could look at what was coming out of my curing rack. Then I picked ONE recipe after reviewing my notes and testing my soaps, and then made several batches to see if I was getting consistent results.

Of course, not every batch is going to be exactly the same unless you are a robot in a climate controlled environment and even then, there is no guarantee unless you have complete control over your ingredients. I've been fairly consistent until the last two weeks...our weather is changing; it's getting cooler and it's raining. Hubby is looking at building me an insulated box in the garage with a small computer fan to circulate the air inside. I also just ordered a case of dehumidifying packs from the Dollar Store as we sometimes get condensation on the inside of our vehicle windows and those should work for my box.

Is your insulated box to use just while your soap saponifies? If so you don’t need a fan or dehumidifier at that stage. The insulated box (I use a polystyrene box with a lid) will keep the environment around the soap stable.

As you cure your soap if you do not have sufficient airflow around your soap or it is really humid inside your house then a dehumidifier might help every so often. You can buy these really cheaply on the net.

 

[TheGecko]

Is your insulated box to use just while your soap saponifies? If so you don’t need a fan or dehumidifier at that stage. The insulated box (I use a polystyrene box with a lid) will keep the environment around the soap stable.

As you cure your soap if you do not have sufficient airflow around your soap or it is really humid inside your house then a dehumidifier might help every so often. You can buy these really cheaply on the net.

The box will be to cure the soaps in. My garage is not well insulated and we get a lot of rain during the winter, so I’m looking at cold (40 degree) and damp...not the best environment to cure your soaps in. Hubby is okay with me saponifying a few well covered loaves in the house, but no way could I cure dozens of bars of different soaps...the scents would be overwhelming.

If I have a good size box to help mitigate the cold and damp, I may only have to extend curing time a couple weeks instead of months.

 

[MickeyRat]

I'm just a hobbyist, not a pro. I used to use wood molds but, I got sick of lining them. So, I switched to 10" silicone molds. I don't really know what the minimum time is but, I've not had a problem unmolding after 24 to 36 hours. I do cover the top with a piece of cardboard wrap with a towel for that period. That seems to prevent cracking on top.

 

[dixiedragon]

I have found that replacing water with vinegar makes the soap harden up faster in the mold, so you get those nice, sharp corners vs those mushed corners. However, on the flip side, you will have a bit less time to swirl, etc.

I know some people use sodium lactate for this reason but I've never tried it.

 

[Nanette]

I generally unmold at 24 hours for my 3 lb molds...but as stated different recipes have different results, meaning some recipes will be very solid at 24 hours, some may have soft edges still and those can be left in the mold another day if you want. Keep good notes with all your recipes and youll know what to expect, or how to tweak in the future. I do gel my soaps and I dont use sodium lactate--I keep forgetting too.

 

[MickeyRat]

I have found that replacing water with vinegar makes the soap harden up faster in the mold, so you get those nice, sharp corners vs those mushed corners. However, on the flip side, you will have a bit less time to swirl, etc.

I know some people use sodium lactate for this reason but I've never tried it.

I'm not saying that doesn't work but, I'm pretty sure that when you do that, you're neutralizing some of the lye. Given that lye is a strong base and vinegar is a weak acid, it's probably not a lot but, you might be getting a bit more superfat than you expect. I have no explanation for why it would harden faster. DeeAnna seems to know the most about the chemistry. Perhaps she'll chime in.

I add about 1/2 teaspoon of non-iodized salt PPO to help with hardening.

 

[earlene]

Mickey, there are threads here on the forum that go into the specific calculations for vinegar replacement in lye solution. I'm pretty sure dixiedragon has utilized those calculations (see first link below).

There are some variables, which include how much vinegar replaces water. For example if one were to replace all of the water with vinegar (which for me was too much as it made my soap brittle) more NaOH is needed to offset the vinegar. But with only a portion of the water replaced by vinegar then less NaOH is needed to offset the vinegar. By going the second route in a 500 gram total batch size soap, this makes negligible difference in the resulting SF. In a larger batch, it would of course. So it depends on a few factors: batch size, percentage of water used to replace water, target SF, and possible other factors as well (other additives, etc.)

https://www.soapmakingforum.com/threads/replacing-water-with-vinegar.73429/
https://www.soapmakingforum.com/threads/how-to-use-vinegar-to-harden-your-soap.59295/#post-588321
https://www.soapmakingforum.com/threads/testing-vinegar-sodium-acetate-in-soap-phase-ii.59148/
https://www.soapmakingforum.com/threads/hard-vinegar-soap.68661/