Hot process soap is a fantastic method to create homemade soap from scratch. Similar to cold process soaping in many ways, hot process involves “cooking” the soap which speeds up the saponification process. In this Soap Queen TV video, I demonstrate how to create natural Lavender & Lemongrass Hot Process Soap in the crock pot. The extra heat cuts down dramatically on wait time! Hot process soap is ready to unmold within 24 hours, and does not require the 4-6 week cure time. Personally, I still like to allow my hot process soaps to cure for about 2 weeks to allow excess water to evaporate and create a harder bar.
This hot process recipe uses a combination of Lavender 40/42 Essential Oil and Lemongrass Essential Oil for a blend that’s both fresh and calming. The light green color is created with green zeolite clay and spirulina powder. Lavender buds are added to the top of the soap for a chic and rustic look. For a charming finishing touch, I used a crinkle cutter. To help avoid drag marks from the lavender buds, I recommend flipping the loaf upside down and cutting from the bottom.
What You’ll Need:
2 lb Wood Loaf Mold
Silicone Liner for 2 lb Wood Mold
2.1 oz. Sweet Almond Oil (Note: In the video the amount of Sweet Almond Oil is 12.1, which is incorrect. I apologize for the confusion!)
1 oz. Avocado Butter
4.2 oz. Coconut Oil
8.4 oz. Olive Oil
4.2 oz. Palm Oil
1 oz. Shea Butter
2.9 oz. Sodium Hydroxide Lye
6.9 oz. Distilled Water
.6 oz. Sodium Lactate
Spirulina Powder
Green Zeolite Clay
Lavender Buds
.8 oz. Lemongrass Essential Oil
.6 oz. Lavender 40/42 Essential
Optional: Crinkle Cutter
Click here to add everything you need for this project to your Bramble Berry shopping cart!
Have you made hot process soap before? I love to use the hot process method when I need my soap quickly!
Would using French green clay work the same as Zeolite Clay?
Yes, French green clay will work well in this recipe. You can add it the same way as the zeolite clay. They are slightly different shades, so your bars will look different than the ones pictures above.
French green clay: https://www.brambleberry.com/French-Green-Clay-P6444.aspx
Hi, thank you for this wonderful recipe. I totally got hooked on soapmaking after watching your YouTube video a while ago and now I’m looking forward to making my first batch of soap.
To be honest, I would love to try this recipe… but considering how limited my experience is with soapmaking, I’m going to follow your basic and gentle cold process soap recipe 😀 If I want to scent my soap with lavender and lemongrass essential oils so that it will smell like this one, would you please tell me how much lavender and lemongrass essential oils should be added to the basic recipe? Thank you in advance.
You can use our Fragrance Calculator to find out how much to add to that recipe: https://www.brambleberry.com/Pages/Fragrance-Calculator.aspx
When blending essential oils, you’ll want to find the strong usage rate for both and make sure not to go over that. For instance, if you want to add 2 ounces of scent, the lavender and the lemongrass need to add up to 2 ounces. So, you can do a 1:1, 2:1, etc., as long as it adds up to 2. If you add both and use 4 ounces, that would be over the usage rate. This post talks more about that: https://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/how-to-blend-essential-oils-safely/
-Kelsey with Bramble Berry
Dear brambleberry team, I just made this soap yesterday and cutted it today. Thanks for this recipe and video! My lavender buds don’t stick very well to the soap, is there a trick to make it adhere better? Thank you and greetings from the Grand Duchy of Luxembourg 🙂
You’re welcome, glad you’re enjoying the recipe! The lavender buds will fall off the soap as you use it. To help them stick a little longer, sprinkle on a handful and then press them in firmly. Make sure to wear gloves as the soap is pretty hot.
-Kelsey with Bramble Berry
I an allergic to nuts so was wondering if the sweet almond oil in the soap would cause a reaction? I know when I ingest nuts I break out but never thought about it in soaps.
Nut allergies are most common when ingested, but to be extra careful we recommend avoiding them in soap as well. Learn more about working with allergies and sensitivities here: https://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/soaping-with-allergies-nuts-gluten-more/
You can use avocado oil in place of sweet almond. They have a similar lightweight feeling: https://www.brambleberry.com/avocado-oil-p3198.aspx
-Kelsey with Bramble Berry
Hi there!
I was wondering if I could use BB liquid green oxide instead of the spirulina powder? If so, how much for this recipe? TIA!
We don’t recommend the glycerin colors for cold and hot process. We’ve found they can cause beading or glycerin rivers. You can use another liquid colorant though, like a LabColor: https://www.brambleberry.com/LabColors-C171.aspx
You can also use a pigment mixed with a lightweight liquid oil. Green Chrome is really lovely in soap: https://www.brambleberry.com/Green-Chrome-Oxide-Pigment-P4042.aspx
Learn more about working with pigments here: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/talk-it-out-tuesday-colorants/
-Kelsey with Bramble Berry
I used your video for the recipe amounts, I had to throw our the batch because I added too much almond oil. The second try worked better but I found it hard to mix the colorants into the batch, it was very thick. I ended up with a brownish, dark greenish color that didnt get mixed in very well. Mine did not look anything close to your picture. Do you have any recommendations, could I add a little water if this happens again? Thank you!!
Absolutely. How long did you cook the soap for? It may be the cook time – if it’s under cooked, it will have hard chunks that still need to be mixed in. If it’s overcooked, it may start to get dry and flaky. The best time to add colors is when it’s the consistency of mashed potatoes and has a gel-like appearance. If you find it’s a bit too thick, you can add a bit more distilled water to loosen it up.
-Kelsey with Bramble Berry
Hi! I am new to soap making. Two questions about the recipe. The ingredients says 6.9oz of distilled water. Is that in total, or just for making the lye water? If I was to omit the spirulina powder and zeolite clay, should I then decrease the distilled water by 2Tbsp? And when I mix in the essential oils can I mix the lavender buds into the soap? I like the idea of having them dispersed throughout the soap rather than on top.
The 6.9 oz. is just for the lye water, it doesn’t count for the clay. So, if you skip the colorants, you don’t need to adjust the recipe at all. Also, you can add lavender buds to the soap. They do turn brown in the soap, so that’s something to keep in mind. They’re still fine to use, it’s just an aesthetic issue.
-Kelsey with Bramble Berry
I used a the 9 cavity silicon mold for this recipe and when the soap pops out of the mold it looks like there are air spaces throughout — almost as if I didn’t pack the soap down enough. Once done cooking, it was the same consistency as mashed potatoes – is there a way to get all the air out? I did tap it and shake it a bit but perhaps a loaf mold is better for the hot process. Do you have any tips for this?
Hot process soap is pretty thick, so it tends to get more air trapped inside than cold process. To get rid of those pockets, place your mold on a hard surface like a cutting board. As you’re filling the cavities, firmly tap the cutting board with the mold on top several times throughout the process to settle it. The cutting board will allow you to get a bit more impact with the tapping and it will settle all the cavities at once.
-Kelsey with Bramble Berry
Hi there
Just started making soap. I would like to kno what what is the substitute for sodium lactate. I live in South Africa
You can use a salt water solution instead! That can help make the soap a bit more fluid. To make the solution, mix 1 teaspoon of regular table salt into 1 ounce (by weight) of warm distilled water. Stir until the salt is fully dissolved. We recommend 1 teaspoon of salt in 1 ounce of water per pound of soap. Make sure to discount the salt water solution from your liquid amount. Then, add the solution at trace. 🙂
-Kelsey with Bramble Berry
Thank you for informative tutorial. I was wondering about the usage rate of Essential oils in hot process and cold process. HP is less harsh for essential oils rather than CP, but here seems the same usage rate for HP is considered.
The bramble berry Fragrance Calc also have option for cp and liquid not for HP. Would you please make it clear for me? I am sure somewhere in your website you have covered this topic (adding essential oils and usage rate for different products) but I can not find those pages. that would be great if you mention the links.
Thanks a lot
You’ll want to use the cold process category on the Fragrance Calculator for hot process soap! Sorry for any confusion. The cold process section gives you the correct usage rates for essential oils. 🙂
Fragrance Calculator: https://www.brambleberry.com/Pages/Fragrance-Calculator.aspx
-Kelsey with Bramble Berry
Hello. I needed to confirm something. After soap has cooked, do I need to wait for it to cool down a little before adding colorants and fragrances? Thank you
You can add those colorants and fragrances when the soap is still warm! When the soap starts to cool down it begins to harden fairly quickly. Adding the colors and fragrances when the soap is still warm gives you more time to work with them. 🙂
-Kelsey with Bramble Berry
Hello. Is there a printable recipe for this soap?
Thanks
We don’t have a printable recipe for this one, sorry about that Ilona! You can find instructions in the video though. 🙂
-Kelsey with Bramble Berry
Hi,
Is there any oil I can substitute with Avocado Butter? I have just about every other oil other than that! I’m in a pinch and need to make this batch by this weekend and do not want to wait some days for ordering and shipping online. Send help!
Coffee butter is a great substitute for avocado butter! If you don’t have that on hand, you can increase the shea butter in the recipe. Shea butter is a bit more firm than avocado butter so the bars will be a bit more firm. They will still feel really nice though. 🙂
Make sure to run the recipe through the Lye Calculator after any substitutions: https://www.brambleberry.com/Pages/Lye-Calculator.aspx
This post has more tips on how to substitute oils in cold process recipes: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/how-to-substitute-oil-in-cold-process-recipes/
-Kelsey with Bramble Berry
While cold process is my preferred soap because designs/patterns are virtually unlimited, I do love hot process and recommend it if you have not tried it. My favorite way is to take cold process soap (any color scheme you want) , cube it (small cubes) and add it to the hot process at the end, just prior to molding. It makes a great looking bar! Another thing I love about hot process is the superfat. My recipe calls for 5%, but it has a high coconut oil percent so I like a higher superfat. Once the soap is cooked and ready to mold, it is soap with no lye so this is a great opportunity to add your extra superfat. I usually add castor oil (no more than 1 to 1.5 oz for my recipe), stir it well and mold and I have an awesome bar of hot process soap. Another great thing is no glycerine rivers and no soda ash! I just made some one week ago and am going to try one this weekend. See it on youtube.com under theorgelmeister.
That sounds so pretty! I love the way embeds look in soap. It’s a great way to use leftover soap as well. 🙂
-Kelsey with Bramble Berry
Hello I am looking to try this recipe, but I have a question. What size crock pot should I use? Thanks again for all that the team at brambleberry do! You guys rock!
Hi Ayanna!
You’ll want a Crock-Pot that’s a bit larger. As hot process cooks it can expand, so you only want the soap to fill about half the pot. I would recommend a 4 or 6 quart Crock-Pot for this recipe. A 6 quart one would be better for larger recipes! 🙂
-Kelsey with Bramble Berry
Can another oil be used as a substitute for Palm Oil?
Palm oil adds some great firmness to your soap, and there is no direct replacement for it. You can add certain oils and butters to help firm your soap up though! For instance, adding a hard butter, like cocoa butter up to 15%, can harden the bars. You can also add tallow up to 33%. 🙂
Read more about common oils and what properties they add to soap here: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/free-beginners-guide-to-soapmaking-common-soapmaking-oils/
This post on substituting oils has some great information too: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/how-to-substitute-oil-in-cold-process-recipes/
-Kelsey with Bramble Berry
Hi Kelsey,
Thank you so much. I have the soap crafting book and looked up hot process but didn’t have insulation info in it. You are all wonderful.
Many thanks
Kate 🙂
You’re very welcome Kate! 🙂
-Kelsey with Bramble Berry
Hi,
one more question does this soap need to be insulated for 24hrs or just covered with cling film and left to rest?
Many thanks
Kate 🙂
Hot process soap doesn’t need to be insulated! As it cooks in the Crock-Pot, it goes through the saponification process fully. That means by the time it’s spooned in the mold, it is already soap and technically ready to use (after it hardens overnight). That is different than cold process, which takes about two days to fully saponify and turn into soap. Cooking hot process soap forces it through gel phase, which is what happens when you cover cold process soap. So, you can leave that soap at room temperature overnight. It will likely be ready to unmold the next day. 🙂
Read more about gel phase here: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/gel-phase/
-Kelsey with Bramble Berry
Hi,
I’m using the silicone loaf mould 50 oz one. I’ve recalculated the lye but with the Spirulina and Zeolite clay should I use 1.5 tsp in 1.5 tbsp of oil and water respectively?
Many Thanks
Kate 🙂
Hi Kate!
I think that would be a great idea! That way you know you have enough color. You can even prep 2 teaspoons into 2 tablespoons to be on the extra safe side. 🙂
-Kelsey with Bramble Berry
Hello! I made this recipe a few weeks ago and it was a pretty green. As is cures, it’s turning a mossy, almost brown green. I used all the same ingredients. Could this be due to the olive oil used? Any suggestions?
Thanks ! Love the site!
Also, my lavender buds are falling off everywhere and turning brown!
Hi Amel!
As the soap cures, the spirulina can fade slightly. However, we didn’t notice any browning with the recipe. Did you make any recipe substitutions at all? Also, lavender buds are a natural ingredient, so they do turn brown over time. That is normal with natural ingredients like lavender buds and rose petals. Let me know and I’ll help you troubleshoot!
-Kelsey with Bramble Berry
Hi,
Probably a really silly question but make a mistake and money down the drain!!! So the butters and waxes come in solid form and need to be melted down. My question is, the amount of oz needed is that in solid form or liquid form?
Thanks so much 🙂
No worries Kate, we are happy to help! The butters will weigh the same in solid form as liquid form. We like to measure most of our recipes by weight instead of volume. We find that’s a bit more accurate. So, you can melt the butters and waxes before adding them to the Crock-Pot, or add them in solid form and melt them in the pot. 🙂
Read more about weight vs volume here: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/a-guide-to-weight-vs-volume/
-Kelsey with Bramble Berry
Thanks Kelsey – also can I use the 10″ silicone loaf mould – I know this holds more soap but was thinking i could multiply ingredients by 1.5 to fit this mould?
Thanks so much 🙂
You can use the 10″ Silicone Loaf Mold! It holds about 1 pound more soap than this one. We have a really great posts that shows you how to resize recipes. I’ll link that below. 🙂
How to Resize Cold Process Soap Recipes: https://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/how-to-resize-cold-process-soap-recipes/
-Kelsey with Bramble Berry
Could this recipe be used in cold pressed method?
Hi Nitza!
Absolutely, this recipe would work for cold process soap as well. I would recommend pouring the soap around medium trace. That way the lavender buds will sit nicely on top. 🙂
See an example of medium trace here: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/trace/
-Kelsey with Bramble Berry
I just topped a CP soap with lavender buds and there was a lot of discoloring around them. Is this what usually happens or could there be another explanation, like using old buds, only sprinkling them on instead of putting a solid base that would cover any discoloration on the soap, etc.
Also, would adding lavender buds into the soap base at trace also cause browning?
Thanks!
Hi Jen!
That is normal with natural products like lavender. Eventually, they will all turn brown. There can be a bit of mold growth on the plants as well. That’s something to keep in mind when using fresh products!
Learn more about using botanicals in soap here: https://www.youtube.com/watch?v=G3VbeNl1Nqg
-Kelsey with Bramble Berry
Hi, I love your site, but I haven’t done any recipe yet. it’s because i’ quite beginner in cold process soaps and i don’t want to do these big amounts and second, i’m from Europe and it’s hard to convert it in kg.
and I have a big demand – could you give a % of used oils? it would helped me a lot to adapt a recipe to smaller quantities:) many thanks in advance, and congratulations on your great job:)
Hi Adwena!
Thank you so much for your great suggestion! We’ll definitely keep that in mind for future blog posts. 🙂
Also, you can figure out the percentages using our Lye Calculator! Just enter the oil amounts, select a 5% superfat and hit “Calculate.” It will show the percentages of each oil next to the ounce amounts.
Lye Calculator: https://www.brambleberry.com/Pages/Lye-Calculator.aspx
This post on how to resize recipes may be helpful for you as well: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/how-to-resize-cold-process-soap-recipes/
-Kelsey with Bramble Berry
Hi guys just wondering if you could help me troubleshoot something. Every time I put rose geranium essential oil in my cold process soap it would start To get tiny lumps straight away, similar to ricing. However, I don’t get this problem with hot process. Just wondering do you think this would be ricing? And if so is this common to using rose geranium oil? I am baffled as it doesn’t happen with any other oils. Thanks guys
Hi Amanda!
It does sound like the rose geranium essential oil is causing some ricing in your cold process soap. My guess is that the reason why it does not cause ricing in your hot process soap, is because by the time you add fragrance to hot process, the soap has gone through more of the saponification process than cold process. Therefore, the soap does not contain as much active lye for the essential oil to react with.
How essential oils behave in cold process soap can vary dramatically. Rose essential oils in particular are known for being difficult to work with in soap. If you find that your soap is ricing when you add the essential oil to the soap, you may be able to stick blend the lumps out of the batter :). I’ve included a blog post below that has more info on pesky fragrance and essential oils. I hope this helps Amanda (great name by the way!) 🙂
Soap Behaving Badly: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/soap-behaving-badly/
-Amanda with Bramble Berry
Thanks so much Amanda! That is very helpful 😀
You’re very welcome! 🙂
-Amanda with Bramble Berry
I’m new to hot process and plan on making this soon, but the video and the ingredients list above have different amounts for the sweet almond oil. Is it 12.1oz or 2.1oz. Thanks.
Hi Sheila!
That recipe amount is 2.1 ounces of sweet almond oil. Sorry for any confusion, and thank you for catching that! We’ll get the blog updated with a note about those differences. 🙂
-Kelsey with Bramble Berry
I really want to try this recipe and I even purchased a cheap crock pot this week just to make this bar but….. I don’t use palm oil. What is your suggestion of an oil to replace the palm in this recipe?? Also when you use sodium lactate, can you water discount? I purchased some sodium lactate from you but haven’t tried it yet. Thank you 🙂
Hi Annie!
Palm oil adds some great firmness to your soap, and there is no direct replacement for it. However, you can use tallow to help firm the soap up! You can use it up to 30% in your recipe. 🙂
Read more about how to substitute oil in cold process soap here: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/how-to-substitute-oil-in-cold-process-recipes/
If you don’t have tallow, you can make a recipe with other oils. For instance, you can replace the palm with olive or rice bran oil. You can add up to 30% coconut oil and 15% of a hard butter, like cocoa butter, to add firmness. We have a lot of great palm free recipes you may like. I’ll include links below. 🙂
Palm Free Vertical Twist: http://www.soapqueen.com/bath-and-body-tutorials/cold-process-soap/palm-free-vertical-twist-tutorial/
Palm Free In The Pot Swirl: http://www.soapqueen.com/bath-and-body-tutorials/cold-process-soap/a-palm-free-in-the-pot-swirl/
Formulating Cold Process Recipes: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/formulating-cold-process-recipes/
Any of those recipes would work nicely for this design! You can resize them using our Lye Calculator: http://www.soapqueen.com/bath-and-body-tutorials/cold-process-soap/using-the-bramble-berry-lye-calculator-2/
As for a water discount, you can do that if you like! Hot process soap speeds up the saponification process and hardens the soap up more quickly. During the cooking, most of the water is cooked off. A water discount can help, but I think the cooking process on its own will harden your soap up quickly. Also, you can definitely add sodium lactate. That helps make the soap more smooth. 🙂
Read more about water discounting here: http://www.soapqueen.com/bath-and-body-tutorials/tips-and-tricks/water-discounting-cold-process-soap-how-why/
-Kelsey with Bramble Berry
Is there something else I could put on the top of my soap? I don’t like the mess that lavender buds make!
Hi Nancy!
Absolutely, you can top this soap with anything you like! Jojoba beads or glitter would look really pretty on top. You could also sprinkle a shimmery mica, like King’s Gold. The combination of green and gold would give the soap a nice holiday feel. 🙂
King’s Gold Mica: https://www.brambleberry.com/Kings-Gold-Mica-P6224.aspx
Jojoba beads: https://www.brambleberry.com/Jojoba-Beads-C125.aspx
Iridescent glitter: https://www.brambleberry.com/Iridescent-Glitter-P3976.aspx
You could also top the soap with curls or scraps from another loaf. That adds a really unique look to the top of it. We did that with the Cherry Blossom Glitter Cold Process: http://www.soapqueen.com/bath-and-body-tutorials/cold-process-soap/cherry-blossom-glitter-cold-process/
Just make sure to press the scraps in so they stick to your soap. 🙂
-Kelsey with Bramble Berry
Thanks! I really need to give this a try.
You’re welcome! Have fun trying this recipe out. 🙂
-Kelsey with Bramble Berry
Great tutorial! I have just started making HP soap (having made CP for some time). I really like it as I don’t have to worry about partial gel or acceleration, which is much more relaxing 🙂 . Plus I find it less messy for some reason :). Kelsey from the team has answered so many of my questions re hot process soaping over the past few weeks. I am very grateful for the support you guys provide!
You’re welcome Amanda, we are happy to help! When we were talking about hot process I was excited for you to see this video. Perfect timing! Hope you get a chance to try it. 🙂
-Kelsey with Bramble Berry