So, a bunch more misc. starting soap making questions

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Well-Known Member
Oct 1, 2021
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Houston, Texas
I made a few batches, promptly forgot almost everything after getting busy at work and having to take time off from the hobby, then started watching youtube videos again on hot process soap making. But they all seem to leave some fine details uncovered. Lots of miscellaneous questions, both theoretical and what I experienced a few times:

1. Trace. I get what it is I think - when you spoon some cooking soap out and let it drizzle back in, it doesn't just immediately rejoin the mass of soap, but it leaves little trails on top that take at least a few seconds to rejoin the mass. But, what EXACTLY is the relevance of trace? I'll first give a few things I don't think it is, then one or two it might be, but that brings up more questions!

Is it the point in time where you shut off the heat completely? I don't think so.

Is it the point in time where you add colors and fragrances? I don't think so.

Is it the point in time where you pour the soap into the mold(s)? I don't think so.

Is it the point in time when you stop stirring? Maybe this. But if so, what happens if you keep stirring longer? Any negative ramifications? Or if you stir it with a stick blender REALLY well, but quit before it gets to trace, any negative ramifications there?

What other relevance might it have?

2. What is the best heat to cook your soap? I think generally lower is better, but what is ideal? Is there an approximate temperature that, if you hit that, the soap will be done cooking in a reasonable time (half hour to hour), and it will do minimal damage to the fatty acids thus minimizing the risk of soap going rancid, developing orange spots, etc.?

Along these lines, I bought a $10 crock pot copycat recently. It has high, low and warm. Is there a best temp? Its weird, but I think based on what I read on the internet high and low probably hit like 210 degrees F, but the high keeps it there longer and the low lets it fall a bit more before turning on the heat again. Then the warm is like closer to 170 F? I don't have a crock pot per se, but a cheapie slow cooker. I have no clue about its real temperatures.

3. What is the IDEAL point to stop cooking your soap and pour it in the mold? Is it AS SOON AS the zap test does not zap you at all? What is the danger of stopping the cooking process and pouring it in the mold when the zap test still zaps you? I actually cooked a batch that I thought for sure was done cooking, poured it in the mold, did the zap test on a little soap I pulled out of the mold, and ZAP, it got me. But the soap came out really good actually. So if you have thoroughly mixed your soap, can you not just pour in the mold immediately and let it finish doing its thing in the mold over days and weeks? Any downside?

What are downsides to cooking it longer, other than excess water evaporating and the soap being hard to get into the mold and look nice?

4. I had a batch where I was cooking it and it was seemingly not done based on the zap test, but it was getting very hard to stir. I was worried I would not be able to get it out of the crock pot into the mold effectively. So I added (what I think) was a little water, but maybe a bit more than a little. It got real gooey. I figured no problem, I'll keep cooking it to get rid of the water. So I cooked it a LONG time, overnight actually, although on the "warm" temp. But the next morning, it was still gooey. So I figured maybe it was the heat that was keeping it from solidifying, so I went ahead and poured it into several silicone soap molds. Many days, even weeks, later it was still gooey and nasty, it had not hardened.

Same thing with some "rebatched" soap - I melted it, added some water, and stirred it on the heat in a crock pot copy, let it cooking for a loooong time, but it got gooey and nasty and did not harden even after weeks in the molds. I had to throw it away.

Any ideas what went wrong where you can literally turn it into soap that will not harden even after weeks?

Thanks for any help on any of this!!!
These can contain what are only my opinions!

1- trace in HP isn't overly important as it is in CP. In HP you don't have to get it in to a mould quickly, or start doing different colours and so on, you add the scent after the cook etc etc. It's a good point to know that you don't have to blend any more and can just switch to stirring if you haven't already

2- maybe try it on warm and see how it goes. Each machine is different and what works for you might not work for me. I even find a difference if I melt the oils in the slow cooker or not - I need a different setting to avoid issues

3- I would cook until it doesn't zap anymore, otherwise what is the point of HP? (Don't say "no cure" because HP does very much need a cure. It's safe to use, but no where near ready!)

4- without more information there is nothing to say here. What was the recipe, how did you cook it, how long etc etc etc. Will be very hard as you can't say how much water you added to loosen it up
You're obviously following HP instructions. As @The Efficacious Gentleman already pointed out, “trace” isn't an important thing that you're aiming for in HP. It's of paramount importance for CP, though. Trace is when you spoon out/let dribble back some soap batter without having heated it and it leaves a trace for at least a few seconds on the surface of CP batter. The only tools you need for that is a stick blender/whisk/spatula, and time.

The states of CP are unstable → stable emulsion, and then the different states of trace; and these are really only important when you are doing CP swirl designs that call for a specific batter viscosity. Also keep in mind that you have only a very small window in the early “life” of a CP soap to adjust the final composition (water content, fragrances, colours).

In HP, you are watching the viscosity/texture too, but the steps are different: First you emulsify the oils + lye (like in CP), usually with a stick blender. But then, you start heating. Heat might reverse emulsification to some degree (splitting/oils separating), but that's not a big failure and will even out by itself quickly.
The steps that the batter crosses, have different names, identified by characteristic appearance: applesauce, mashed potato, gel/vaseline. These names might sound simplistic/unscientific, but they really nail how the batter behaves.
And, most importantly, they tell you when the cooking is done! As long as the batter is still opaque (mashed potato or earlier), there are still unreacted oils in it; when you stop there, it might be the case that these oils separate and the soap bar feels oily and crumbles apart. The transition to vaseline phase (translucent, sticky jelly texture) happens surprisingly quickly and is easy to detect. Now the soapmaking reaction is finished, and it's time for final assembly (post-cook additions, moulding). The only purpose of further cooking at this point is to get rid of surplus water.

Unfortunately one can not predict how long HP cooking takes. Too many variables (batch size, heat input, shape of the pot, lye concentration/water content, evaporation losses, oil blend, …).

Incidentally, the vaseline state coincides with the time at which the batter isn't zappy any more. IF you are adding all the oils at the beginning. But if you have saved oils for post-cook superfat addition, your initial batter is around 0% SF, hence might be slightly zappy even if fully done. In this case, the better test to monitor the saponification progress is the clarity test (dissolve a bit of the batter in hot distilled water – if it stays clear, all oils have reacted).
Re: question #3. Since in HP, processing the soap through saponification is the goal, then the average HPer would not stop early to pour into the mold. But if it is plain soap without a lot of post-cook additives, there is nothing wrong with pouring into the mold before the soap is zap-free so long as it is fully incorporated (can no longer separate). Saponification continues while in the mold because once it starts, it doesn't stop. Otherwise, why would anyone use the CP method? (There are benefits to CP, but that is for another discussion.)

Re: question #1. The benefit of knowing that you have reached trace, is that you know it has not only reached, but moved beyond emulsion, meaning the ingredients should not separate after this point, unless something is adding to pull the batter out of emulsion. Another benefit is that if & when you choose to try your hand at CP soapmaking, you are prepared for a very important step in the process of Cold Process.

In HP you don't need to stir as vigorously after trace, but you do still stir because you don't want the soap on the outer edges to burn. And as TEG mentioned, with using a crock pots & slow cookers, there are so many variables with them, especially when using an older one or a cheaply made one, the amount of heat in yours versus mine or anyone else's, simply will not necessarily be the same even if we use the same setting, which BTW also vary greatly with different brands.
Re #3- yes stop cooking as soon as it's zap free.

Re # 4 there is no benefit in cooking soap so long. Usually mine cook in 20-30 minutes, but I cook them hot. Even on low I've never had a batch take more than 45.

No idea why your soap wouldn't harden. Can you give us more info on your recipe?

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