Thursday, July 27, 2006

Hot Process Hints

For me, the hot process method is the quickest and easiest way to make soap. There is very little room for error and the soap turns out great 99% of the time. Still, there is that 1%, so I thought I'd try to shed some light on some common HP problems and how to easily solve them.

By no means is this a comprehensive list, but hopefully it will help you if you’re having trouble with your HP. Please bear in mind that my observations take into account that the recipe being used isn't flawed and that the equipment used (slow cooker, double boiler, oven, etc) is in good working order.

1. My soap is really thick and I have trouble getting it into the mold.

This is probably the most common problem with making HP soap. Fortunately, it's also the easiest to solve. Thick soap is usually caused by a lack of water, so it's important never to do a water discount with HP. In fact, it's a good idea to add an additional 5-10% to the recommended full water amount. I wouldn't suggest going over 10% as the extra evaporation while the soap cures can cause the sliced bars to warp or bend. The extra water may be added to the lye solution or even to the finished soap before it goes into the mold. I have 'thinned' out many a batch of thick soap by adding a small amount of hot water at the end of the cook, but it does require careful and lengthy stirring to fully incorporate into the soap.

In addition to extra water, there are a couple of additives that can help keep the soap more fluid. Adding 3-5% sugar to the lye solution before the lye is added can help keep the soap from getting too thick. It is imperative that all of the sugar is dissolved before the lye goes in or you'll end up with a caustic boiled sweet! Sodium lactate is another additive that can keep soap fluid, however, add no more than 5% or the soap can become brittle. Sodium lactate is a forgiving ingredient and may be added at any time during the soap making process. I prefer adding it at trace.

2. My soap has lumpy bits in it.

When I first started making HP, I had the lumpiest soap ever. Even the cured bars showed the tell-tale white spots. There are two main reasons for hard lumps in soap -- over-heating and over-cooking. In my experience, HP should never be brought to a temperature over 140F (60C). Doing so causes the indirect heat source to become more direct as the sides of the pot or slow cooker heat up enough to over-cook or burn the soap. The hot sides contact the soap, causing bits to over-heat and harden. While harmless, these hard bits will affect the look of the finished soap.

As with cooking soap at too high a temperature, cooking it too long will also cause lumps. A longer cook time means more evaporation -- and evaporation means harder, thicker soap. As the soap continues to over-cook, the soap will begin to form hard lumps. I have rarely had a batch of soap of any size which required cooking for more than 45 minutes.

3. My soap zaps!

Barring any mistakes with the recipe, zapping soap is undercooked. To avoid a heat or lye burn, soap shouldn't be zap tested (touching a small amount of cooked soap to the tongue) at all without meeting a few criteria first:

- Soap should be at the gel stage and there should be no parts of the soap that are not translucent. If the soap resembles cake batter in any way, do not touch it.

- Soap should be cooled before testing. While 140F isn't boiling, it can still burn.

- Soap should be rubbed between the fingers before testing. If the soap feels waxy and smooth, it's fairly safe to test, but if there are any rough or gritty bits, it should not be touched to the tongue.

If you’ve met the criteria and the soap zaps, simply cook it a bit longer.

These tips won’t solve every problem you might encounter with HP, but hopefully they’ll help you achieve more trouble free batches. If you have any hints you’d like to add, please leave me a comment. My hope is that by sharing, we can make HP a nearly fool-proof method!


mathilda said...

I shall try the sugar and extra water. My HP always looks 'rustic', ie: lumpy as hell.I must have been over-cooking it.

Any hints on how much turmeric to add to a pound of base oils for a strong yellow?

gracefruit said...

Hi mathilda! I don't think I've ever used turmeric. I have used paprika with pretty good success -- 1 heaping tablespoon per kilo of oils. Maybe the turmeric would work like that? Sorry I'm not more help!

Anonymous said...

Thanks so much for the excellent tips Elizabeth! The one that helped me most was the one about the thickness of the soap before scooping it into the mold. It helps to know that adding a little more water will help and not hurt the soap recipe. I just started making HP soap about a little over a month ago with Crock Pot and I have to admit that I'm now in love and prefer HP to any other process there is simply because it seems to be a lot easier and you can also use it almost right away. I love it!

Thanks for what you do.

gracefruit said...

Hi Vikki, isn't HP a blast? I love it because it's so hard to get wrong, which makes it excellent for beginners.

Happy soaping!

Anonymous said...

Oh yes, I love it so very much. I have a question for you though. Have you ever used Lanolin with HP?

I just opened a blog page myself but I don't really know anything about it lol. How do I get started? What do I post? I know it sounds lame but I'm just really lost. Thanks,Vikki

gracefruit said...

Hi Vikki, I've not tried lanolin, but I have used squalane which is very nice. I added a small amount once the soap had fully cooked. I'm sure you could do the same with lanolin.

Just write about what you love and enjoy. It gets REALLY easy after that. :)

E x

Mocha said...

I actually used it in a batch a week ago and I think it turned out nicely but I've been hearing something about it being heat sensitive or something to that effect. So I just wanted to get someone else's opinion on using the Lanolin. I'm going to actually try it tonight and I'll tell you how it feels and what I think. The fact that some people has bragged on how dreamy it makes the soap is what made me want to try it.

Thanks for the tip. Of course what I love is Soap so I guess I'll start there.


Anonymous said...

Thanks for your blog! Very helpful. We tried the HP today and our recipe had to stir for hours for it to even trace (we need to get a blender!) and then cooked for another 2 hrs to looks like it was ready to pour into molds. Only we tried the zap test, and were zapped!! how can it still be caustic after cooking for so long? We have been using recpies from a soapmaking book so it seems odd. Also with both recipes today the thick soap (just when it looked ready to pour) separated and there was additional liquid in the crock pot which looked like water...have you had any experience with that? thanks!!!

gracefruit said...

Hi there. The liquid at the end was probably glycerine. Sometimes it will 'float' on top of the cooked soap. You just need to stir it back in.

Without seeing your recipe, I can only guess that the lye content was too high. You can check your recipe by running it through a lye calculator ( to make sure you're using the correct amount of lye. I have seen many mistakes with lye in books, so it's always a good idea to check.

I hope this is helpful to you!

Anonymous said...

I just made yummy mocha coffee bars with leftover coffee from this morning in lieu of water, and I used the grounds in the soap for an exfoliater. I did forget to add the castor oil ( I just had twins so my heads a little screwy) and my soap took FOREVER to come to trace, then 10 more years to gel and finish. I put my recipe into the lye calculator minus the castor oil I forgot to add and there was a substantial difference in amount. So if it takes forever, there is probably too much lye. However, it was well worth the wait! The soap is the most amazing shade of brown and smells divine!

Wadawas said...

Hi Gracefruit,

Have you ever found that extreme summer heat + high humidity messes with the crock pot or the soap?

I've been CPHP fro 2 years without ever having a problem. But last week my soap didn't work out & i don't know why. Perfect measurements, perfect trace. But the soap was gritty with pools on top. Eventually it was completely gelled through & passed all other criteria for being finished, but i still zapped. This was after 8 hours of cooking!!! This happened to 3 batched in 3 days (different crock pots) all during the crazy hot & humid weather.

The only other thing i could think of is that all of my oils were hotter than usual when i added the dye.

Do you have any insights?

Wadawas said...

sorry, i meant when i added my lye. Sigh, i wish we could edit blog posts!

gracefruit said...

Hi Bunny! Living in Scotland, I must confess that I've never made soap in high heat or humidity. :) I know plenty of soapers in the US that do regularly make soap when then weather is hot, though.

If your soap is coming out lye heavy, it might be that your scale is a bit off, or that the caustic soda you're using has gone out of date.

I do hope you figure out what's causing the problem. Failed batches are annoying!

Wadawas said...

LOL - not one scortching hot day? Maybe i should move to Scotland!

I just had my scale replaced, so it's shouldn't be off. Do you know of a sure way to test it?

I don't even see an expiry date on my lye! oy!

Does it matter in CPHP if the oils & crock pot are already very hot when the lye is added?

gracefruit said...

Bunny, I've never worried much about temperature when making HP and have never noticed any ill effects. It is possible to burn the soap if your crock pot is set too high, but other than that, I don't think there is any harm in having a hot pot or hot oils -- just be careful not to burn yourself! :)

Anonymous said...

Hi Gracefruit!
I have yet another question for you:
I would like to add water based liquids after the cook. Have you ever done this? I was wondering if you had an idea of what % could add without creating an extreme long wait time for the soap to dry.

Fylith said...

Gracefruit, my soap keeps puffing up and over flowing my crock pot! it tests out at PH of 9 but it doesnt have that vasaline look to it. if i stir it up it settles down but by then i have lost alot of soap over the edge. i use a 8 L crock pot and i make about 5 lbs of soap. i made the recipe as follows.
26 oz of coconut oil
28 oz of palm oil
26 oz of soybean oil

11.5 oz of lye
30.5 oz of water

am I doing something wrong? i was told not to stir my soap until i put in my FO and color. but if i dont over the edge it goes.
thanks a bunch

Vikki said...


I'm not Grace but from what I can see your recipe is fine. There is absolutely nothing at all wrong with stirring your batch back down when it starts to puff up to the top. It's actually recommended that you do this.

I use a 6 1/2 quart crock pot to do my 4 to 5 lb batch in and I have to stir my 5 lb batch down most times so I'm not sure if maybe your crockpot is too small for the job or not being that it's an 8 lb batch that you are working with.

I hope this helps.

fylith said...

Vikki, thanks so much I will just watch it very carefully and stir it when it puffs up. thanks for letting me know my recipe looked ok :)

Mocha said...

Anytime Fylith! Your recipe has nice cleansing, conditioning and hardness qualities. I'm sure your soaps will turn out great!


fylith said...

Vikki or grace... so i made my soap and it didnt puff up this time but now it zaps. it called for 11.6 oz of lie i only put in 11.5 but it is still zaping even after cooking it 3hrs and adding 5 oz or more oils in what did i do wrong this time. im so frustrated. :(

Anonymous said...

Hi, gracefruit seems to not be on lately, so can anyone let me know if they have experience adding water liquids after the cook (like teas, for example). I would like to what % liquid i can add ofter the cook & still have my soap set.

Mocha said...

Hi Fylith,

What it sounds like to me is that you probably didn't get your batch to a true trace. When this happened to me I just let it cook cook cook until I touched it to my tongue and I didn't get the zap. My batch turned out great after that.

Sorry that it took me so long to get back to you as I had attend a funeral Saturday.

Mocha said...

Anonymous, it actually depends on how much water maximum that your recipe calls for. If you don't use the max at the beginning then you can make up for it in the end if you don't get carried away. I wouldn't add anymore than what I left out from the discount at the beginning.

I hope this helps.

The Spinner's Cottage said...

Hello, I am new to soapmaking and tried a cold process batch last night. Not happy with the 45 minutes with a whisk in order to get it to begin to trace and not sure if it will saponify correctly. Can I reheat this batch and turn it into a hot process batch instead?
Thanks and I absolutely LOVE your website.

Anonymous said...

Hi, I'm new to HP soap, and twice I've tried this exact method, with different HP recipes Twice now I've had it cooking for 16 + hours at about 170* with no translucency. I threw out the first batch and so want to save this one... any suggestions? Should I be adding water during the cooking process? Help! :D

Anonymous said...

Hi all,I was wondering about the adding sugar at 3-5% to the lye that 3-5% of the water amount or the batch weight ,or oil weight?

Anonymous said...

Same thing here is the 3-5% oil weight or lye water weight?

Anonymous said...

My soap came to trace too fast and I have been cooking it four-eveh-errrrrr and it still zaps! What in the world is going on? I figured too much lye and not enough oils and waters so I tried to re batch with extra water and oil and have been stiring like a mad woman and so far no change. It's zap city! Help?!?
Thanks :)

bued said...

Prior to trying the HP Crockpot recipe I'd like to ensure that my crockpot doesn't get too hot. I am especially concerned about the temperature at the sides (I wish to avoid lumps). Do you recommend that I use a candy thermometer and hold immerse it on the side to check the temperature? Also, how far should I immerse.

Thank you so much for sharing your talents! -Rhonda-