Bath bombs are fairly simple to make, but to get that lovely extra foaming ability you need a surfactant like SLSa, you could substitute this for SCI, but SLSa is better for this purpose. This will give it that extra wow from swirls of soft foamy bubbles instead of that underwhelming fizz ;)
There’s a lot of negativity surrounding SLSa, and there shouldn’t be. Instead of going by ‘free from’ adverts without any facts, let’s dive into what SLSa is exactly and why you should or shouldn’t use it in skincare and bath products.
SLSa (Sodium Lauryl Sulfoacetate ) is an anionic surfactant of coconut and sustainable palm origin, and much milder than SLS. It’s a non-irritant with a pH between 5 and 7.5 which for the purpose of a Bath bomb is fine.
It dissolves well in water and lathers up well which is why we want it for our Bath bomb as it creates a great lather that lasts.
Wear a respirator when working with powder surfactants like SLSa. It is dangerous and unpleasant to breathe.
Here is where the confusion comes in. Many people will lump SLSa in with SLS (Sodium Lauryl Sulfate) which is different. SLS is a cheaper lab made surfactant, whereas SLSa is a naturally derived surfactant. SLSa molecules are too large to penetrate the skin and therefore don’t irritate the skin like sulphates.
In short. SLSa is a safe, non-irritating naturally derived surfactant that lathers and foams well, with excellent cleansing properties and so is a great addition to you Bath bombs and cleansing products such as bubble bars, bubble bath and shampoo.
Usually paired with secondary surfactant. In the case of our Bath bombs, we are using Polysorbate 80 for its ability to solubilise the oils into the bath water instead of leaving an oily film around the bath. If you were making a bubble bath or shampoo you could pair it with cocamidopropyl Betaine as these would either not contain oils, or also contain some sort of emulsifying agent instead.
For the rest of our recipe, we’ve added the required citric acid and bicarb to get that fizz and colour and fragrance to make it more fun :) Then so long as you can make the texture of wet sand to compact it, you can add some nice additions. We’ve chosen sweet almond oil and arrowroot powder, but be aware of but allergies with these ingredients. Some people may be sensitive to sweet almond oil and the arrowroot although not an allergen itself, may have been packaged on food lines dealing with nuts, soy and gluten. You could use cornstarch or kaolin clay instead. Using cornstarch helps to slow the reaction of the bomb and help it float (though floating isn’t necessary, some people like them to).
If you are making these with kids and don’t want the worry of using SLSa and respirators, then replace the arrowroot and SLSa with cornstarch. You won’t get as much of a foam, but it will float and fizz and be altogether safer for them to make.
You can use whatever oils you like and I’d add in vitamin e as an antioxidant for the oils and for its nice properties.
Formula and Recipe for a 200g Batch – 1-2 sphere bombs depending on size
You'll notice that I separate this out into a lot of phases, this is because we want to add the Citric near the end to avoid accidentally activating the mixture. If you added it in phase A and then added your phase B wet ingredients, it could activate in the bowl, so we add that at the end.
I gave the colours a separate phase as it's just easier to add them once the mix is made. If you are using pre-dispersed liquid colours, you can add them in the oil phase B, but you'd need to then have two separate batches.
Bicarbonate of Soda 60% (120g)
SLSa 2% (4g)
Arrowroot Powder 2.5% (5g)
Sweet Almond Oil 2.5% (5g)
Polysorbate 80 1% (2g)
Fragrance 1.5% (3g)
Citric Acid 30% (60g)
Colour 0.5% (1g) UP TO - In the video I'm using our own fluorescent neon non-bleed pigments in purple and green.
· Wear a respirator for SLSa
· Mix Bicarb, SLSa and Arrowroot in a bowl.
· Add wet ingredients (almond oil, polysorbate 80, fragrance oil) and mix with gloved hands until you have the texture of wet sand, so that you can easily compact the mixture. Be thorough, you want it completely mixed.
· Add the Citric acid and mix again with your gloved hands. We add this last to avoid the mix reacting as the Citric is essentially the activator.
· Divide into bowls and add your different colours and mix more.
· Compact it into moulds and turn out to dry. If making spheres like us, fill each side then pile some mix on top of one half. Squeeze the two halves together compacting the mixture. DO NOT TWIST. Gently tap the mould on the table all sides and then gently remove. Use a muffin tray with some cling film to dry your sphere bombs so that they don’t get flat bottoms.
· Avoid rooms that are too humid as it may activate your bath bombs before they are ready. You can buy humidity meters online. A dehumidifier is a good purchase if you live in a humid area.
· The above recipe is fairly basic and variations are available online from various creators, so have a play around and find a formula that works for you. I’ve tried varying amounts of bicarb to citric and ½ citric to 1 bicarb seems to be a good balance to get the best results in my opinion.
· You can change up the colours, fragrance and oil to your preference.
· You can change the SLSa for a different surfactant like SCI if you wish, but our experiments have shown SLSa to give the best foam/bubble payoff.
· Swap out arrowroot for cornstarch or Kaolin depending on your preference.
· If you don’t want too much foam, then you can omit the SLSa entirely and up the arrowroot/kaolin/cornstarch content. The Polysorbate 80 will still be required as a solubilizer, this ingredient is non-negotiable really, as nothing else solubilizes in the same way, especially since this is an oil-based formula. You will need it to avoid a horrible oily film around your bath after using the product.
· You can change up the moulds you use and paint them with Mica and Isopropyl mixtures.
· Be sure to take the amount of colour as an ‘up-to’ amount. You can get away with a fair amount for bath bombs, but some pigments can stain both the skin and baths, so use enough for colour payoff without going too nuts.
· Don’t forget to calculate your fragrance oil allergens and mark them clearly on your labels.
· To package bath bombs, provided they are in a cool dry environment you can leave them as they are or pop a paper band around them to label, or you can shrink wrap them or use bio-degradable cellophane bags or glassine bags as a few ideas.
· If your bath bomb making goes wrong, such as not compacting and turning to dust or breaking apart or partially activating, then salvage what you can and create a bag of ‘bath dust’ or ‘bath rocks’ to sell, as these are just as appealing and mean that you won’t be wasting product.
Disclaimer: These formulas and recipes are experiments created for the purpose of sharing on Patreon and YouTube. Revega does not make any claims as to their qualifications or the efficacy of the formulations which are listed here for entertainment purposes and accepts no responsibility for how you use these. We are self-taught and offer these videos from our years of knowledge and experience in making our own cosmetic products.
Remember that if you intend to use one of these formulations for your own product range, do your own research, experiments, adjustments and tests before using, gifting or selling.