Today we’re making a lovely solid conditioner bar starring exotic passionfruit oil and richly conditioning BTMS-25! When you run this solid bar over wet hair, it transforms into creamy, slippy hair conditioner—leaving your hair soft and silky, taming flyaways and improving comb-through. It’s quite simple to make, and one bar can last up to a year depending on how often you use it!
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The biggest difference between this conditioner bar and other conditioner bar formulations I’ve shared in the past is that it uses solely BTMS-25 as its solid conditioning ingredient. I’ve heard from lots of readers and viewers that they can only get BTMS-25 where they live, so this formulation is accessible to those people!
BTMS-25 contains 25% Behentrimonium Methosulfate (the active conditioning ingredient), while the other 75% is cetearyl alcohol. In contrast, BTMS-50 contains 50% Behentrimonium Methosulfate, with the remaining 50% comprised of cetyl alcohol and butylene glycol. That means BTMS-25 contains half of the active ingredient, but far more thickening/hardening ingredients. That means if you replace BTMS-50 with BTMS-25 in an emulsion, the BTMS-25 version will be thicker, but less conditioning.
This conditioner bar formula (and last year’s Cranberry Orange Conditioner Bar) grew out of a sample formulation from Dow for a “Zen Conditioner Bar” that I found on UL Prospector. I’ve been riffing on that formulation since summer 2019, and at this point, the only thing I haven’t changed at some point is the Behentrimonium Methosulfate concentration (15%)—though I’m sure that’ll happen soon! One thing I really like about this formulation is the inclusion of a small amount of water. I use a lot less than the sample formulation does, but it’s still enough to dissolve water-soluble solids like panthenol powder and prevent that funny wavy top completely anhydrous conditioner bars develop as they cool.
In addition to 60% BTMS-25, these conditioner bars also include some luxurious passionfruit oil and virgin coconut oil. You’ll also find another 17% cetearyl alcohol for further hardening. I find one of the biggest characteristics a conditioner bar needs to nail is the melting point; it needs to be hard enough to survive being rubbed on heads on dropped in the shower, but it also needs to melt (just enough) when rubbed on wet skin and hair. Too hard, and it’s like running an eraser over your hair. Too soft, and you get way too much product in your hair, the bar breaks down far too quickly, and you might get a “splat” instead of a “thunk” when you inevitably drop it!
For scent, I’m using the ultra-juicy passionfruit natural fragrance oil from Essential Wholesale, but you could easily use any sort of fragrance or essential oil you love! You could also leave the bar unscented if you prefer; simply replace the fragrance oil with more water or passionfruit oil.
The finished conditioner bar is beautiful; it easily deposits an even coating of conditioner over hair (and skin, if desired), leaving it feeling richly conditioned and easy to comb through. Shelf-life wise, I’ve had a few of last summer’s experiments living in my shower for close to a year now, and they’re all doing brilliantly. Enjoy!
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Passionfruit Coconut Conditioner Bar
0.75g | 1.5% hydrolyzed oat protein (USA / Canada)
0.5g | 1% cetrimonium chloride (USA / Canada)
0.5g | 1% panthenol powder (vitamin B5)
0.5g | 1% passion fruit natural fragrance oil
0.5g | 1% Optiphen™ Plus (USA / Canada)
2.25g | 4.5% distilled water
Preheat your oven to 200°F/93°C. You’ll need three heat-resistant beakers or glass measuring cups for this project.
Weigh the heated phase ingredients into a small heat-resistant glass measuring cup or beaker. Pour some distilled water (I used about 40mL for a 50g [1.76oz] batch) into a second beaker or heat resistant glass measuring cup. The amount of water isn’t really important as we’ll be weighing it out later once it’s hot—just make sure you have enough water in there that it’s not all going to evaporate in the oven while you heat it up.
Place both beakers on a baking tray and pop that in your preheated oven for about 20 minutes, until the oil mixture has melted through and the water is nice and hot.
While the heated phase is heating up/melting, weigh the secondary phase ingredients into that third beaker. At this point, it’s also a good idea to get your mould ready and clear out a spot in your freezer that is large enough for the filled mould to rest flat.
Once the heated phase is melted/hot, we’re ready to combine everything. We want to move quickly at this point, so be sure you know exactly what you need to do and you have everything at hand before you remove the tray from the oven. REMEMBER! The things that were in the oven will be hot. Make sure you are wearing oven mitts whenever you touch them!
Remove the heated phase from the oven. Weigh the correct amount of pre-heated distilled water into the secondary phase and whisk to combine. Once that mixture is uniform, add it to the melted BTMS/oils mixture and stir to combine. Once that is uniform, pour it into your mould.
To decorate, sprinkle some mica over the bar and quickly swirl with a toothpick or similar thin instrument.
Carefully transfer the mould to the freezer and freeze until solid (at least half an hour). When the bar is solid, gently unmould it and leave it to dry for at least two days before using it.
To use, simply glide the bar over wet hair after shampooing, leave it in for a minute or two (I usually shave my legs in that time), and rinse clean. That’s it! I recommend storing the bar somewhere it can drain and dry out between uses; I have a wire rack in my shower that works beautifully.
Shelf Life & Storage
Because this conditioner contains water and will frequently be in contact with 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 50g, which is a good-sized conditioner bar that will likely last a single person close to a year.
- 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 (panthenol) please look up the ingredient in the encyclopedia before asking.
- I don’t recommend swapping out the BTMS-25 or cetearyl alcohol. If you do, you will be in re-development territory as the biggest challenge in conditioner bar development is balancing the melting point/hardness of the bar, and those two ingredients are 77% of the formulation and have a huge impact on the melting point/hardness.
- If you only have BTMS-50, I recommend this formulation instead.
- You could use a different liquid oil instead of passionfruit oil.
- Babassu oil will work instead of coconut oil; you could also use more passionfruit oil.
- You can use a different hydrolyzed protein instead of oat, like quinoa or rice.
- You could try polyquaternium 7 or honeyquat instead of cetrimonium chloride, or use more distilled water.
- If you’re like to use a different preservative, please review this page and read this. I selected Optiphen Plus because of its high heat tolerance; keep that in mind when choosing alternatives.