Hot Process

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Jack

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Having been removed from another group for discussing "off topic" subjects like making lye and hot process, I hope I am among more tolerant folks here.

I am interested in hot process soap making for a number of reasons but am having a great deal of trouble finding any useful information on the subject.

My interests or goals in soap making are to make hard soap from wood ash lye and to make hard soap from corn oil. So far I have made a lot more progress on the latter but not much on the former.

There is enough "chatter" out there to lead one to believe that hard soap can be made with KOH but usually with the kicker that it must be hot processed.

I purchased Dunn's book but learned more about lab procedures than soap making and nothing about hot process or KOH use. I have a very good pH meter and lots of hydrometers but he dismisses them out of hand.

I have about a gallon of 30B lye that I made from fireplace ash over the past few weeks so I have a handle on that process but know next to nothing about hot process.

Anyone out there interested in this?

Thanks,

Jack
 
I have no help for you, but I have to say that I followed your wool shirt adventures a few years ago. I wish I could rememeber what weaving and spinning message board I was on, but I remember you were the poster child for 'Yes, you can spin and weave your own clothing.' :D
 
Ive herd you can make hard bars from KOH but i wouldnt recomend it. You need to add extra KOH than recommended. then you run the risk of having lye heavy soap. Stick with NaOH. You can use it for HP hard bars. The process is extreamly similar to making liquid soap but you dont add the water at the end and you have to (very quickly) put the gel into the molds. (from what ive read) Its really hard to manipulate the gel to make designs. I know nothing about making lye but if your planning on making pure corn oil bars this is what comes up in the Lye calculator
Hardness 14 (suggested range 29-54)
Cleansing 0 (suggested range 12-22)
Conditioning 84 (suggested range 44-69)
Bubbly 0 (suggested range 14-46)
Creamy 14 (suggested range 16-48)
Iodine 117 (suggested range 41-70)
INS 69 (suggested range 136-165)

so i STRONGLY recommend adding some coconut oil to these bars.
 
I do hot process almost exclusively. I use a crockpot. It starts out just like cold process-mix your lye and water, melt your oils. You don't need to wait until it's a certain temperature-just pour the lye water into the oil when you're ready. Whisk or stickblend to trace.

Don't add your colors or EOs/FOs at trace like usual, because you're about to cook it.

Set your crockpot on high. Check it every 5-10 minutes, because your soap will probably double in size. Just stir it down if it starts creeping up the sides.

After about a half hour of cooking on high, your soap should have the consistency of vaseline. Check it via zap test (rub the soap between your fingers first and make sure it's waxy before putting it on your tongue) or a PH strip. If it's ready, turn off the heat and add your EOs/FOs and colorant. Glop into a mold and let it harden.

After it's hardened, it should be ready to use. I still suggest letting it sit for 3-5 days before selling it so it hardens up a bit more.

I personally prefer this method over cold process because I don't have to worry about soda ash, partial gels, or a long curing time.
 
If it's about soap, it's not off topic. :)

There are a lot of soapers on this board who hot process soap. Squigglz posted a good overview, and there are some links to tutorials with pictures in this thread http://www.soapmakingforum.com/f11/just-beginning-31002/ You can probably find a lot more information if you search a bit, it comes up pretty often.

As far as making lye with woodash, the general feeling I get from most people when the topic comes up is that they have not tried, because it is difficult to get a consistent concentration and that KOH generally leads to soft or liquid soap. I wonder though, since usually when I see discussion about making KOH from woodash comes up someone always brings up people who do it as historical re-enactments, if you contacted a group like the SCA if you could find someone with first hand experience at it. As far as I know (and I could be wrong) no one on this board has actually done it, just looked at the theory of how to do it.
 
I am having problems with just what is meant by hot processing as the various methods seem to gray into one another.

Dunn mixes his soap and cooks it at 140F in an oven for 4 hours.

The crock pot method uses much higher temps and regular stirring for indefinite time periods.

We also read about boiling the mix, sometimes for days and sometimes mentioning boiling of the oil, which could be really scary.

Then we have additions of water, lye and even oil during the boil and soap floating to the top where separation is the operative.

The latter seems like the more common commercial method but I wonder why they go to so much trouble if the other methods produce the same results.

The Dunn method works really well for single bar experiments and this is what I have been using with a spare toaster oven.

It's not clear why this works as well as the crockpot and regular stirring but
the crockpot does not lend itself to single bars so I abandoned that for the present.

I guess I am rambling but maybe it will generate some opinions of the different approaches.

And yes, I am wearing a homegrown shirt, trousers, vest and socks as I type. That first shirt was a real challenge and would never have happened without the help for the spinning and weaving fora. There is lots more of that on my fiber page.

Jack
 
I see why you are geting a bit confused :)

The Dunn method you are referring to is usually referred to as CPHP or cold process oven process. What you are actually doing is forcing the gel stage. Most people who use this only leave the oven on for an hour, probably bevcause the lowest temps on a full size oven are usually 170F.

A full hot process method is where you "cook" the soap until sponification is complete and there is no lye left, then add your fragrances, colours, and whatnot and put into molds. It does involve higher temps than CPOP, but has the advantage of being able to add fragrances and other additives that generally don't survive CP, and being able to control your superfat, plus a generally lower cure time.

The other ones you mentioned I am not personally familiar with, but I am sure someone will come along who is ;)
 
I see why you are geting a bit confused :)

The Dunn method you are referring to is usually referred to as CPHP or cold process oven process. What you are actually doing is forcing the gel stage. Most people who use this only leave the oven on for an hour, probably bevcause the lowest temps on a full size oven are usually 170F.

A full hot process method is where you "cook" the soap until sponification is complete and there is no lye left, then add your fragrances, colours, and whatnot and put into molds. It does involve higher temps than CPOP, but has the advantage of being able to add fragrances and other additives that generally don't survive CP, and being able to control your superfat, plus a generally lower cure time.

The other ones you mentioned I am not personally familiar with, but I am sure someone will come along who is ;)


What is CPOP method? I am confused about how it is cold process if you'er putting it in the oven.
 
What is CPOP method? I am confused about how it is cold process if you're putting it in the oven.

Cold Process Oven Process is used to ensure complete gel phase. You would CP your soap as usual, mold it, then put it in a warm oven to reach gel phase. It's basically the same as insulating your mold to encourage gel, just a more precise way, with a more controlled temperature. Some soapers do this to encourage/force quicker saponification, in the hopes of being able to shorten their cure time and use the soap sooner. (I still think it needs a 4 week cure, btw.)
 
I see why you are geting a bit confused :)

Most people who use this only leave the oven on for an hour, probably bevcause the lowest temps on a full size oven are usually 170F.

That's why I treasure my old oven. It will hold 100F for ever and is great for proofing bread and making yogurt. But the good news is that small toaster ovens have no problem holding 140 but of course are batch size limited.

>A full hot process method is where you "cook" the soap until sponification is complete and there is no lye left....

There is another confusion for me. There are visual indications of saponification and one can measure the pH but it's not clear how you know it is "complete" or that there is no lye left.

My experience has been that either in the oven or simulated mini crockpot, the pH always comes out over 11+ and after 24 hours drops into the low 10 range.

First of all, it seems intuitive that if all the lye was used up, the pH would be near 7 where the distilled water used started but I guess I slept through that chem lecture.

This obviously is not the case but I would think that one should be able to measure the pH and know that saponification is complete but this also assumes that the correct amount of lye was used.

I have a lab quality pH meter but it's not much help if I don't really understand the process. It's only been about two weeks since I got back into this but none of these soaps are less than pH 10. I found a bar that I made about 20 years ago left from a batch made in accordance with the instructions on the Lye label and it's 9.3 and a very nice soap.

Jack
 
I can't really help with the pH questions. I test to see if any lye is left by doing the zap test. With HP, you would do this by taking a tiny bit out, letting it cool enough to touch, rubbing it on your finger and then touching your tongue to it. If there is still active lye, it will zap, kind of like a 9 volt battery
 
Jack, if that is how you feel about the lye pH, then why don't you do a test batch and use pH strips to see where it um... lyes? :D (Sorry that really wasn't intended but once it came to mind I couldn't help it)!Sometimes jsut trying something, you will see what is supposed to happen and you'll feel better about it once you get it. I have also heard that even with hot process, the soap might still be slightly alkeli when it cooks, but will settle as it cures for a couple days.
 
>A full hot process method is where you "cook" the soap until sponification is complete and there is no lye left....

There is another confusion for me. There are visual indications of saponification and one can measure the pH but it's not clear how you know it is "complete" or that there is no lye left.

Make sure to double check your recipe-if it's still testing as having unused lye in it, you're using too much. I cook my hot process soap for a half hour on high in the crockpot, at most 45 minutes, and it'll be done. A good visual is if there's still 'white soap' (whiter stuff when you stir), that white soap isn't done yet so cover it and let it cook for a bit more. When it's done, it should look like vaseline and feel waxy if you rub it between your fingers.

I CAN, in fact, make individual bars with it-I can use the same molds for it as I do cold process and melt and pour. I just prefer log molds and the more 'rustic' look they give.


Jack said:
My experience has been that either in the oven or simulated mini crockpot, the pH always comes out over 11+ and after 24 hours drops into the low 10 range.

First of all, it seems intuitive that if all the lye was used up, the pH would be near 7 where the distilled water used started but I guess I slept through that chem lecture.

Most of the 'big name' soaps actually have a PH closer to 10-mostly 9-9.5 to 10. Dove is a 7, though. So basically, I wouldn't wait to see if it tests at 7, because you could be waiting quite a long time. Apparently there's a way to lower the PH by rebaching and adding boric acid, but I've never tried that.

Disclaimer: I don't use PH strips to test, I do the zap test. I do know I'm right about the store soaps, though.
 
Last edited:
HELP!! HP NEWBIE! SOAP Saponified instantly

This is my first time making a batch I was intending to use as baby shower favors. I waited until both Lye and oils in crock pot had cooled down to same temperature. Since I had melted my oils in the crock pot, I had to remove it from the base so it could cool down faster. I then placed it back in the crock pot and mixed both using a stick blender to get a med Trace.

I cooked for 1hr. stirring. It instantly turned super hard... after about 1/2 an hour it turned back into apple sauce consistency. when the hour and 1/2 was up i was waiting for it to cool down a bit so i could add my fragrance but it turned into crumbled soap. I added the oil anyway. I knew it would flash but I had to melt it or it wasn't going to be a solid piece of soap.


The recipe was
6.5 Palm Oil
6.5 Shea butter
7.5 oz Olive Oil
1.3 oz Castor Oil
8 oz Water
3.1 oz Lye
1 oz Frangrane

HELP!!! what did I do wrong?
 
Sounds like it cooked for too long and it dried out which is why it was crumbly. You should have added more water to get it back to a mashed potato consistency.
For future reference, its better to make a new post then bring up one that is over a year old.
 
Make a new post in the CP soap forum. Is your soap still in the pot? Can you possibly get a picture? I would add 1/4 cup water and turn it onto low and try and get it back to a goopy stage so you can mold it.

EDIT: I just ran your recipe through soapcalc, its lye heavy. Where did you get this recipe from? The way it is, its not usable unless you add some more oil to it. I would add 3 more oz of olive oil, that will bring the superfat level back to 5% which is the default for handmade soap.
 
You just saved my life!

It was in the crock pot. I added more water, got it to a gooey consistency and placed in the mold.

So this soap wont be usable? even if I cooked it for almost an hour and 1/2? Probably more counting the time I added the water.

I got the recipe from here:
http://candleandsoap.about.com/od/soaprecipes/r/basic4oilsoaprecipe.htm

I changed the coconut oil to shea butter. I should've known better than to do that without running it through the soapcal. I know different oils have different properties and fat content.

Thank you so much for your help. This was my first batch ever and thankfully I only made 2lb since I knew I would make mistakes and didnt want to waste all my product.
 
It won't be safe because it will still have lye in it. No amount of cooking will neutralize lye if there isn't enough oil for the lye to interact with. When ever you replace a oil, it always needs to be ran through a lye calc. I hate to be the bringer of bad news but it needs to go back into the crock pot so you can add more oil.
If you try to use it like it is, it will be very drying at best or cause a chemical burn at the worse.

Its a pain to keep rebatching but at least it's a easy fix and your oils won't be wasted. You may need to add a bit more water again but I'd just do 1 Tbs at a time, you don't want it too runny.
 
It won't be safe because it will still have lye in it. No amount of cooking will neutralize lye if there isn't enough oil for the lye to interact with. When ever you replace a oil, it always needs to be ran through a lye calc. I hate to be the bringer of bad news but it needs to go back into the crock pot so you can add more oil.
If you try to use it like it is, it will be very drying at best or cause a chemical burn at the worse.

Its a pain to keep rebatching but at least it's a easy fix and your oils won't be wasted. You may need to add a bit more water again but I'd just do 1 Tbs at a time, you don't want it too runny.

What effect will that have on the fragrance? I've cooked it so much I'm way past flash. Do I need to add another ounce? or should I just leave it as is?
Out of curiosity... what soapcal are you using? how can I see what percentage of Lye I'm in now?

This is the one I use-
http://www.brambleberry.com/pages/Lye-Calculator.aspx

And it doesn't give me that option.
 

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