Our summery Watermelon Mint series continues today with a simple Watermelon Mint Foaming Hand Wash that pumps out thick clouds of the most decadent lather, making handwashing a treat. To keep things as easy as possible, I’ve used a pre-blended surfactant product so you don’t need multiple different types of surfactants—making this a great DIY for anyone new to working with surfactants. There’s no heat required, so just measure, stir, wait, and you’re ready to bubble!

How to Make Watermelon Mint Foaming Hand Wash

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The surfactant I’m using in this hand wash, Stepan-Mild® BSB Liquid Surfactant Blend, is the same one I used in my How to Make Easy DIY Hand Wash live stream back in April (Pssst…. that live stream is a great place to get more information on formulating hand washes + customizing this one!). I really loved the handwashes we made in that live stream—the lather was utterly decadent. Rich, slippy, and left the skin feeling cleansed and conditioned. Swoon. So, I’m bringing that lovely surfactant blend back for a proper blog post!


The basic live stream formulation used the surfactant blend at 30%, but that proved to be too viscous for the foamer bottle. If you’ve ever sent something even slightly viscous through a foamer bottle you’ll know the poor foamer cap spits and sputters with each pump, dispensing a watery blob of lather(ish) rather than the clouds of decadent bubbles we want. Thankfully, the foamer cap will transform formulations with lower than usual concentrations of surfactant into mountains of lather, so I reduced the surfactant blend to 15% and the final product is still ultra-lathery.

For scent, I’ve used two ingredients. Peppermint hydrosol brings the minty note, and a small amount of watermelon fragrance oil adds a lovely sweet, fruity note that isn’t overwhelming or too reminiscent of the hair detanglers I used as a kid. If you want to use peppermint essential oil instead of the hydrosol I’ve provided instructions on that in the substitutions list after the formulation.

Since my foamer bottle is clear, I also included a very small amount of a pink/red water-soluble dye. You certainly don’t have to use the dye (simply replace it with more water if you’d rather not), but if you do want to colour this hand wash, be sure to choose something water-soluble. Iron oxides and micas will both settle out of this no-viscosity formulation, leaving a layer of pigment at the bottom of your foamer bottle.

The finished hand wash smells great, cleanses your hands beautifully, and is positively decadent. Enjoy!

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Watermelon Mint Foaming Hand Wash

22.5g | 15% Stepan-Mild® BSB Liquid Surfactant Blend
22.5g | 15% vegetable glycerine (USA / Canada)
0.3g | 0.2% watermelon fragrance oil
0.015g | 0.01% water-soluble red/pink dye
0.45g | 0.3% Liquid Germall Plus™ (USA / Canada)

74.235g | 49.49% distilled water
30g | 20% peppermint hydrosol

Weigh the surfactant blend, vegetable glycerin, fragrance, dye, and liquid germall plus into a measuring cup or beaker and stir to combine. Once that mixture is uniform, gently add the water and peppermint hydrosol. Stir gently until uniform—it’s useful to leave the mixture to sit for 30 minutes or so after a bit of stirring so it can do some dissolving on its own.

Once the mixture is uniform, you’re done! Package it up into a bottle with a foamer top; I used a 250mL cube bottle with a foamer top from YellowBee. I recommend using a clear bottle so you can appreciate the pretty colour of the hand wash.

Use as you would any other hand wash/hand soap. Enjoy!

Shelf Life & Storage

Because this hand wash contains water, you must include a broad-spectrum preservative to ward off microbial growth. This is non-optional. Even with a preservative, this project may eventually spoil as our kitchens are not sterile laboratories, so in the event that you notice any change in colour, scent, or texture, chuck it out and make a fresh batch.


As always, be aware that making substitutions will change the final product. While these swaps won’t break the recipe, you will get a different final product than I did.

  • As I’ve provided this recipe in percentages as well as grams you can easily calculate it to any size using a simple spreadsheet as I’ve explained in this post. As written in grams this recipe will make 150g (approximately 150mL/5 fl oz).
  • To learn more about the ingredients used in this recipe, including why they’re included and what you can substitute them with, please visit the Humblebee & Me Encyclopedia. It doesn’t have everything in it yet, but there’s lots of good information there! If I have not given a specific substitution suggestion in this list please look up the ingredient in the encyclopedia before asking.
  • If you’d prefer a thicker hand wash that will work in a normal pump bottle, simply thicken the hand wash with Liquid Crothix (USA / Canada) or salt at the very end. The instructions for this project serve as a good guideline.
  • You can use a different mild surfactant blend instead of the BSB Liquid Surfactant. Suggestions include Iselux Ultra Mild and Miracare Soft 313.
  • If you want to make your own surfactant blend I’d recommend referring to this formulation for some guidance. You can also look at creating your own blend based on your personal collection; I recommend checking out this table, this FAQ article, and this series of posts to learn more.
  • You could try propanediol instead of vegetable glycerin.
  • The dye is optional; feel free to replace it with more distilled water.
  • If you’d prefer to use peppermint essential oil instead of peppermint hydrosol:
    • Add 0.3% peppermint essential oil when you add the watermelon fragrance oil.
    • Drop the peppermint hydrosol and replace with 19.7% distilled water (29.7% distilled water + 0.3% peppermint essential oil = 20%, to replace the 20% peppermint hydrosol)
  • If you’re like to use a different preservative, please review this page and read this FAQ.

Gifting Disclosure

The foamer bottle and water-soluble red/pink dye were gifted by YellowBee.