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Crock Pot Hot Process Method

Instructions for Crock Pot Hot Process Soap

Making soap in a crock pot is an easy way to use the “Hot Process Method”

These instructions outline the steps for making crock pot soap and assume you are familiar with the soapmaking process.

Start with a good recipe. The one shown below is a good basic recipe. Any recipe can be used for Hot Process Soap, you just need to make sure that the lye calculation is correct.

Follow this link for a great soap lye calculator that I highly recommend –

I prefer recipes that have a higher amount of liquid oil to solids.

One of my favorite recipes is very simple: 60% Olive Oil, 20% Palm Kernel Oil, 20% Palm Oil. Run it through a lye calculator to determine the amount of lye and [distilled] water needed. I don’t discount my water when making hot process.

I use a large crock pot. A 2kg batch of soaps fits perfectly. It fills the crock pot about half to 3/4 full – giving room in the case of it bubbling up, but not too little an amount that it could burn.

First, measure water and set aside.

Measure the lye into a separate container (with digital scales).

Slowly pour the lye into the cold water.

Stir until dissolved. Set aside in a safe place.

Once I have my lye mixture set aside to cool down to 100*F, I measure out my solid oils.

These solid oils can be put into the crock pot to be melted. (it takes longer this way, so I generally put them into the microwave for a couple minutes until melted and then pour into the crockpot).

At this point, my crock pot is on low to gently warm the oils. (TAKING CARE NOT TO OVERHEAT OILS)


Next, measure the olive oil – and/or any other liquid oils you will be using – and pour into the SOLID OILS once melted a little in the crockpot.

The temperature of the lye must cool to 100*F and the Oils must be heated to 100*F.

The lye can be poured INTO the oil mixture – once the temperatures are within a range of 5-10*F of each other – the closer they are to 100*F and each other the better.

Slowly pour the lye mixture into the melted oils.

Stir initially with a spatula or spoon to combine.

Then take out your stickmixer and start to mix it. Giving your mixer a rest every 30 seconds or so.

Use the stickmixer to stir as well so you can monitor progress, lifting it up whilst off – so you can see the texture and viscosity of your soap batter.

Gently move the stickblender around, up, down, around, ensuring a nice even blend.

Keep mixing like this until a good trace is reached.

The consistency of a nice cake batter, that’s right a cake batter!! For HP Crock Pot soap the trace consistency is not essential but you must be sure that you have reached trace.

Once it has reached ‘trace’, I put the lid on the crockpot and turn the heat setting up to high.

However, the first few times I made crock pot soap, I left it on low until I was confident in how it worked (both the soap AND my crockpot). I do recommend this for first timers and until you are used to your specific recipe. Keep in mind that the mixture will rise and you’ll need to stir it down if this happens. Constant monitoring is recommended for this to be achieved.

Now, I ready my mold – this can and should be done now (ahead of time), so that you’re not rushed at the end of cooking, measure out any fragrance oils or essential oils and any additives I plan to use.

After about 30 minutes on high or 60 min on low, I take the lid off and, using a potato masher, mash the soap around to ensure that all has cooked through. Lumpy pieces of white and any parts that look solidish are not cooked enough.

Replace the lid and continue cooking until you are sure that it’s cooked through, this could take 3 lots of 30-40min cooking seasons. Between each cooking season take the lid off and give a really good mix with a spoon, spatula or masher.

The total cooking time can vary a lot, but you’ll reach a point that there are no lumps, the texture is smooth and waxy and if touched it feels waxy, a little hard and does not stick to your finger when touched.

It has a look of a thick vaseline texture; glossy and slick. It will have a waxy feel if you rub a piece of it between gloved fingers.

Another method for testing if it is ready is the ZAP TEST – place a small amount on your tongue and see if it tingles – if it doesn’t tingle, it’s ready. If it tingles, keep cooking.

If your not game to do this, a ph strip is also a great way to test.

You’ll learn when it’s ready mostly by the feel and look of it.

As the cooked/ready soap cools down it will begin to solidify more and quite quickly – so you’ll need to mix in your colour, fragrance and additives quickly so that you can get it into your mould before it’s too hard and difficult.

The hot process soap batter is in a gel state – when its ready and will continue to gel in the mould for a few hours.

Once your soap batter is ready and you’ve tested and are sure that it is ready it is time to instil your creative talents and create your custom designed colours, scents and additives.

Add your additives, colorants, herbs, etc and mix well using the potato masher.

You can if desired, split the batch into various jugs/containers and colour them differently to make colourful two or three tone soaps.

Once that is blended fairly well, add your fragrance and mix again. Then add any botanical ingredients such as lavender/rose buds. mix, mix, mix.

It is done! At this point, it’s soap (not caustic).

It only needs to be put into your mould.

Do this in large spoonfuls, pounding your mould on the counter every few scoops to ensure it packs into the mold tightly, I also get my hands in there and press down to ensure it’s packed in.

The viscosity of Hot Process Soap Batter, is much thicker and glupier than Cold Process Soap Batters.

Once I have it all in the mold, I use my hand and push the top in – making sure to “squish” it into the corners really well.

Now is a good time to wash all the dishes. And you don’t even need to add any soap!

You should see some lovely lather from the soap you’ve just made.

I let this sit over-night. The next morning, I unmold and slice into bars to air out for a week or so.
Once each bar has had time to harden, I bevel each one and it’s ready for use, or sale.

My favorite crock pot soap recipe: You can add any additives or essential oils to this to personalize your bars.

Hot Process Soap Recipes – 1.8kg Batch

– 1077gm olive oil (59.38%)
– 408gm palm kernel oil (22.5%)
– 329gm palm oil (18.13%)
– 251gm sodium hydroxide (5% discount)
– 689gm distilled water

Disclaimer: Sodium Hydroxide is highly caustic and should be handled carefully and knowledgeably. It is the soapmakers responsibility to research safety procedures for soapmaking.

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