If you’re looking for a glossy, slippy, richly hydrating body lotion sort of thing for summer, I think this pretty pink Raspberry Mint Body Custard might just be it. This formulation is unlike emulsion I’ve ever made, with a consistency that puts me in mind of rich custard with a hint of taffy-like plasticity that’s rather fascinating. It stars lightweight raspberry seed oil, hydrating sodium lactate, and an all-natural palm-free emulsifier; I hope you find it as delightful and intriguing as I do!

Want to watch this project instead of read it?

Watch Now

This formulation was a bit of a DIY-ing happy accident. I was aiming to create a natural body yogurt; a formulation with a small oil phase that gets its viscosity in very wobbly way from a gelling ingredient. Back in 2021 I shared a Strawberry Kiwi Body Yogurt formulation that was gelled with Polyacrylate crosspolymer-6 (Sepimax ZEN); in this first stab at a natural riff, I used hydroxyethylcellulose as a natural alternative because it creates clear, carbomer-like gels, which is rather rare in the world of natural gelling/gum ingredients. The end result wasn’t anything like what I was imagining it would be. I was thinking I’d get something that was wobbly and wiggly; instead, it was silky, glossy, and, just… really cool. Not at all yogurty, but sort of… custardy. Hence the name! I highly recommend watching the video so you can see it while it’s stirred and poured because it’s hard to describe the almost elastic quality of this Raspberry Mint Body Custard.

I’m very pleased with a bit of pH-synergy I baked into this formulation. Our preservative, Geogard Ultra™, causes the pH of formulations to drop quite a lot—sometimes enough that a 10% NaOH solution is needed to boost it up a bit. Sodium lactate, a fabulous humectant, causes the pH of our formulations to go up. So, I figured I’d pair sodium lactate with Geogard Ultra™ for awesome hydration + built-in pH regulation. Sodium lactate is not as potent as Geogard Ultra™ when it comes to pH shifts, so I’ve paired 6% of a 60% sodium lactate solution with 1.5% Geogard Ultra™ for a final pH that should land in the 4.5–5 range, depending on how long your distilled water has been open.

Because this is a summery formulation, I’ve kept the oil phase of this formulation small, and the emollients are nice and light. The star emollient is lightweight, golden raspberry seed oil. If you don’t have raspberry seed oil, I’d choose a different light, fruity oil instead—something like apricot kernel oil or cranberry seed oil. It doesn’t have to be fruity (sunflower oil or grapeseed oil would work, too), but a fruity swap would keep the summery/fruity vibe going 😎 I’ve complimented the raspberry seed oil with some ultra-light isoamyl laurate for some emollience and a bit of tack reduction.

Our emulsifier is Montanov™ 202, a new-ish-to-me all-natural emulsifier that boosts the moisturizing properties of our formulations and is made without palm oil. Montanov™ 202 shares a fabulous characteristic with Glyceryl Stearate (and) PEG-100 Stearate; it emulsifies, but it doesn’t thicken. This allows us to choose how we want to thicken our formulations exactly the way we want to, and with this formulation, I’ve used hydroxyethylcellulose. I love the silky, clear, carbomer-like thickening hydroxyethylcellulose brings to formulations, though in this formulation we get more of a taffy/caramelly experience than a jelly/wobbly one. It’s unique, and I like it!

I’ve included a wee bit—just 0.01%—of a potent water-soluble dye to make this Raspberry Mint Body Custard pink. This is the only not-natural ingredient in this formulation, so the formula is 99.99% natural. If you don’t want to use it, simply replace it with more distilled water and you’ll have a 100% natural product.

Want to watch this project instead of read it?

Watch Now

Relevant links & further reading

• Distilled water in the Humblebee & Me Encyclopedia
• Sodium Lactate in the Humblebee & Me Encyclopedia
• Geogard Ultra™ in the Humblebee & Me Encyclopedia
• Hydroxyethylcellulose in the Humblebee & Me Encyclopedia
• Montanov™ 202 in the Humblebee & Me Encyclopedia
• Raspberry Seed Oil in the Humblebee & Me Encyclopedia
• Isoamyl laurate in the Humblebee & Me Encyclopedia
• Cetyl Alcohol in the Humblebee & Me Encyclopedia
• Tocopherol (Vitamin E) in the Humblebee & Me Encyclopedia
• How long will ______ last? What is its shelf life? in the Humblebee & Me FAQ
• Can I use a different preservative than the one you’ve used? in the Humblebee & Me FAQ
• pH
  • pH meter in the Humblebee & Me Encyclopedia
  • pH measurement in cosmetic lab: why we dilute samples? from Skin Chakra
  • How to adjust the pH of your cosmetic products from Skin Chakra
  • Why do you create a 10% dilution of a formulation before measuring the pH? in the Humblebee & Me FAQ
• Other lightweight/summery formulations:
  • Raspberry Mint No-Melt Summer Body Butter
  • Ultra-Light Summer Face Cream
  • Summer Glow Body Oil
  • Summer Solstice Body Milk
  • Watermelon Mint Summer Body Oil

Raspberry Mint Body Custard

Heated water phase
94.068g | 78.39% distilled water
7.2g | 6% sodium lactate (USA / Canada)
0.012g | 0.01% red 40 dye (USA / Canada)
1.8g | 1.5% Geogard Ultra™ (USA / Canada / UK / NZ / Aus / South Africa)
2.4g | 2% hydroxyethylcellulose

Heated oil phase
1.8g | 1.5% Montanov™ 202 (USA / Canada / EU / NZ / AU)
8.4g | 7% raspberry seed oil (USA / Canada)
2.4g | 2% Isoamyl Laurate (USA / Canada / EU)
1.2g | 1% cetyl alcohol (USA / Canada)

Cool down phase
0.24g | 0.2% Vitamin E MT-50 (USA / Canada)
0.48g | 0.4% spearmint essential oil

Prepare a water bath by bringing about 3cm/1″ of water to a bare simmer over low to medium-low heat in a wide, flat-bottomed sauté pan.

Weigh the heated water phase into a small heat-resistant glass measuring cup or glass beaker. Weigh the entire lot (measuring cup + ingredients) and note that weight for use later. Weigh the heated oil phase into a second heat-resistant glass measuring cup. Place both measuring cups in your prepared water bath to melt everything through.

After about 20–30 minutes the oil part should be completely melted and the water part should be thoroughly dissolved. Remove the water bath from the heat and weigh the water phase. Add enough hot distilled water to the heated water phase to bring the weight back up to what it was before heating, and then pour the water part into the oil part. Stir with a flexible silicone spatula to incorporate.

Grab your immersion blender and begin blending the lotion, starting with short bursts so the still-very-liquid lotion doesn’t whirl up and spray everywhere. Blend for about a minute before switching to hand stirring. You’ll need to be fairly diligent with the stirring at first, but once the mixture has thickened up a bit and is uniform you can switch to stirring occasionally. Once the outside of the glass measuring cup is just warm to the touch (40°C or cooler, if you have a thermometer) we’re ready to proceed.

Now it’s time to incorporate our cool down ingredients. Because cool down ingredients are typically present at very low amounts you’ll need to use an accurate scale—preferably one accurate to 0.01g. As these more accurate scales tend to have fairly low (100–200g) maximum weights you won’t be able to put the entire batch of lotion on that scale without blowing it out. So—grab a smaller dish. Add a scoop or two of the emulsion, and then weigh the cool down ingredients into that, using the more accurate scale. Stir to thoroughly incorporate, and then stir all of that back into the master batch. Doing it this way minimizes the amount of cool down ingredients lost to the secondary container.

To test and adjust the pH: create a 10% dilution by weighing 2g product and 18g distilled water into a small bowl or beaker and whisk to combine (wondering why?). Check the pH with your pH meter (I have this one [USA / Canada]). Depending on the shape of your bowl/beaker you may need to tilt it in order to fully submerge the sensor on your pH meter. The pH should fall between 4.5–5. If it’s lower than 4.5 or higher than 5.5, you’ll want to adjust it. Please read this article to learn more about pH adjusting.

Once the cool down phase has been incorporated, all that’s left to do is package it up! I recommend a squeeze bottle or a pump-top bottle.

Use this body custard as you’d use any lotion, taking care not to over-apply. A little goes a long way, so start with less than you think you need. Enjoy!

Shelf Life & Storage

Because this formulation 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 you notice any change in colour, scent, or texture, chuck it out and make a fresh batch.

Substitutions

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

• As I’ve provided this formulation 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 formulation will make 120g, which will fill a 120mL/4 fl oz container nicely.
• To learn more about the ingredients used in this formulation, 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.
• You can try a different humectant, like glycerin or propanediol 1,3, instead of sodium lactate, but if you do this, you’ll need to raise the pH of the formulation with a different ingredient (I’d recommend a 10% NaOH solution).
• The dye is optional; replace it with more water if you don’t want to use it.
• If you’re like to use a different preservative, please review this FAQ and this chart.
• For the hydroxyethylcellulose: I think soft xanthan gum would work as well, though I’d probably only use 1%. I don’t recommend Polyacrylate crosspolymer-6 (Sepimax ZEN) or Ammonium Acryloyldimethyltaurate/VP Copolymer (Aristoflex AVC) as alternatives due to the sodium lactate (electrolytes).
• You can use Glyceryl Stearate (and) PEG-100 Stearate instead of Montanov 202.
• You can substitute another lightweight oil for the raspberry seed oil. I think Cranberry Seed Oil and Apricot Kernel Oil would both be lovely choices that would keep up the fruity, summer theme!
• You can replace the isoamyl laurate with a different lightweight ester, like Coco-Caprylate or Neossance® Hemisqualane. You could also replace it with more raspberry seed oil.
• I don’t recommend substituting the cetyl alcohol, but if you have to, Cetearyl Alcohol is the best choice.
• If you’d like to incorporate a different essential oil, please read this.
• If you’d like to use a mint hydrosol instead of mint essential oil, replace about 30% of the distilled water with the hydrosol and add the dropped 0.5% from the essential oil to the distilled water.
• If you’d like to use a fragrance oil instead of the essential oil, please read this.