How to thicken your handmade products

Castile Soap is awesome, especially Under Your Sink’s Organic Handmade Liquid Castile Soap. Even though it’s a concentrate, it’s not extremely thick & can get a bit runny once diluted further.

Never fear, there are ways you can thicken your liquid creations – but you need to understand a few things first. Let me explain 😊

If your using Castile Soap straight up – undiluted
You can use Castile Soap directly without diluting it down with water, but you may want to be light handed with the pump as its pretty concentrated.

In this case, you can thicken your soap in two easy ways
     1) Essential Oils – Some Essential Oils will automatically thicken your soap like Eucalyptus and Lavender. On the other hand, some essential oils like citrus blends will thin it. I suggest doing a little test to see what the impact is before you start hitting the large quantities.
     2) Saline Solution – the addition of good old iodised table salt will naturally thicken Castile Soap. The smallest amount is needed & there are no hard & fats rules. So, the best way to tackle it is to make a saline solution and add a tiny, tiny bit at a time to see what happens. Also bear in mind it thickens up more over time, so stop adding saline just before the consistency you want.

If you are adding water to your Castile Soap – diluted
Adding water to Castile Soap will only ever thin it out (even if you have thickened it with the methods above) but it's a smart move to get the absolute most out of this liquid gold! To thicken a solution of liquid Castile Soap & water you will need a little hand from Xanthan Gum, a natural thickening agent that is used in a lot of gluten free cooking.  

You only need teeny weeny amount of this stuff to thicken your liquid, but it is a little tricky to mix without becoming clumpy and annoying. Google will give you a few tricks around creating a vortex with some type of blender, but one trick I have found works best is using Organic Vegetable Glycerine to emulsify the xanthan gum first – and then adding that to the liquid.

This great video I found on YouTube shows how different amounts of Xanthan Gum can thicken just plain old water





Under Your Sink

HI Danielle Morgan

Thanks so much for reaching out, I love that your making your own products, so great!!!

Now forgive me if I am wrong here, but I believe that Castor Oil and Coconut Oil do provide better lather but once they are made into soap, not by itself I am afraid. The oils need to be converted though saponification and using Lye, but I am assuming your not making the actual soap since your adding Castile Soap already so those additional oils it will just add moisturizing qualities

This glycerine and xanthan gum trick works to thicken any water based product and with 16oz of distilled water it should work for you. But if you after a bit more lather maybe try adding a teaspoon of grated Coconut Soap, only use a bit as hard soap will want to go hard again and can clog up your bottle.

Please feel free to email me on or hit the Chat on the website and Im happy to talk through this more with you if that helps.

Thank you!!


Danielle Morgan

Help please! I’m making beard was and used the following ratios in and effort to increase soap lather. Originally I just used coconut oil but I was reading that castor oil and almond oil would help with suds. Not sure how to fix this lather. Consistency is good and it smells good. I’m so confused.

– 7 ounces of coconut oil
-2 ounces of castor oil
– 16 oz of Castile Soap (liquid form)
– 20 drops of bergamot
– 20 drops of geranium
-20 drops sage
-20 drops sweet orange
-20 drops cedarwood
– 16 oz of distilled water.
-5 ounces almond oil

Used your instructions below:
1. In the bowl add the Glycerine, Xanthan Gum & essential oils, mix well until it is free of lumps & forms a gel.
2. Add the distilled water & Castile Soap to the gel mixture then gently whisk, try not to make too much bubbles. Keep whisking (for up to 5 minutes) & slowly the mixture with thicken up. 

3. Once you have the desired consistency, pour into your pump bottle & it’s ready to use. Store any leftovers in an airtight bottle. 

Under Your Sink

Hi Claire,
I am so glad you are experimenting with some wonderful recipes – your hand wash sounds lush!

The saline trick will only work with the Castile Soap that has been undiluted and has no other ingredients. So its perfect if you are using Castile Soap as is undiluted and just want it thicker.

If you add water, essential oils or anything else it will not work and that is where the xanthan gum comes in. The good part about xanthan gum is you are literally only using a few grams at a time, a small amount goes a long way so its worth while. It will thicken water based solutions (but not alcohol unfortunately)

One idea is to thicken the Castile so much it turns to a thick paste and then add your water and extra ingredients, see if that gives you the consistency you like.

Hope this helps!
Have fun & happy creating

Under Your Sink

Under Your Sink

Hello Janie,

Thanks for your message, I recommend mixing approx 1/2 to 1 teaspoon of the xanthan gum to 1 tablespoon of glycerine first in the bowl of mixing jug, make sure the jug is big enough to hold all the liquid your making plus a bit more for bubbles :-) It will form a nice gel which is much easier to spread through liquid.

Next add your water and castile soap to the bowl and gently whisk for a while, it can take a few minutes depending on how much you are doing but it will thicken up, yet still be pourable.

You can check out the recipe I use for dish liquid here if this helps, its also my hand wash and body wash :-)

Thank you and good on you for using soap, you’re a legend!

Under Your Sink

Claire Newman

Hi, this is a great post. I added saline solution to my home made hand soap and achieved a really nice consistency but after a few days it went watery again. Do you have any idea why? My hand soap consisted of both essential oils, vegetable glycerin, almond oil and water.

I will try the gum but I was hoping for a cheaper and easier solution. Thank you

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