It is tempting to assume those words mean a perfect recipe with zero concern or worry. However, I think this really does lead people down a frustrating path when they don't work. With experience and understanding of ingredients, we can learn why they work for some but not all, and let's work through some recipes and hopefully get a better understanding for you and get you as far along to your master recipe as we can.
So let’s start with a look at a really simple starter 101 recipe I have seen:
280g Baking Soda
140g Citric Acid
3g Cream of Tartar
15g Grapeseed Oil
10g Fragrance oil (you might need less or more depending on your fragrance)
binder (as needed)
Most of this is cheap and readily available. Also, nearly all of these ingredients can be picked up at the supermarket. This will give you a bubbly fizzy performance however won’t leave foam on the top of the water. This is also lacking in colour. This one is based towards a nice hard bomb, how can you tell?
Well, there are main ingredients with purpose in a bomb, let's go through this recipe:
Baking soda and Citric Acid - This is the main part of the bomb, this gives you the fizz! Bubbling water and reaction to anything humid.
Cornstarch/cream of Tartar/Kaolin Clay/Any clays - This is for hardness, that is to say, once you have mixed and left the bomb to dry this will also react with the humidity.
Grapeseed oil/sunflower oil/almond oil - This is the glue, the lovely lighter oil that holds it together.
Fragrance oil - smelly goodness.. No other function
Binder (which can be Witch Hazel/90 proof alcohol/water or a combination) this is the tiny few sprays when you are really close to the mix coming together if you make the mix too wet it will react and you will end up with a volcano/a reacted non-exciting bomb. If you make it too dry it will crumble and not come together as a uniform shape.
Now with all this in mind let's look at a complicated bath bomb recipe, this has extra ingredients and will do cooler things. Keep in mind, of course, this means it's more expensive and all the ingredients won’t be available at your handy supermarket.
Advanced Bath bomb recipe to try
340gram citric acid
30grams cream of tartar
15mls Sweet Almond oil
Mica (cosmetic grade Mica)
Water Soluble Colourants (we, of course, recommend SOS and Auroradyz)
Water as Binder
So there are some new ingredients in this listing and they will do some super fun things.
SLSA - (Sodium Lauryl Sulfoacetate) This is the foaming agent, the pretty bubbles that sit on the surface. People use this but there are others that aren't as strong such as powdered milk/SCI/etc
Poly80 - (Polysorbate80) In simple terms this is the mixer that means mica/pigments/oils mix into the water instead of sitting on the surface of the water.
Mica - these are great colours for bombs, however, they do not colour the water. Mica is not water-soluble so ends up as tiny glitter specks in the water when used with Poly80.
Water Soluble Colourants - These are the colour bang! Those amazing bright pink baths or deep blue colours. So when the foam clears on the top the beautiful colour underneath and the wow factor. These can also be used/colour the foam on the top.
So keeping this in mind if you were to make this recipe and it wasn’t going hard for some reason you would add more hardener, not bright enough add more colourants etc. This is the place where you take over and need to adjust for your own area and personal preference. We, of course, have a bath bomb help group and are happy to troubleshoot with you also, sometimes it's hard to know what to change exactly to get more foam, faster foam, more bubbles or fewer bubbles.
Now to talk about some things you might come across in other recipes that aren't in the above and maybe you would like to try.
Epsom Salts - These are used and serve a similar function as Citric Acid. Salts are known for of course trace minerals and people like to ‘soak’ for benefits. These are notorious for drawing moisture/humidity into your bombs however and can be the reason you get bumps/bubbles in a mix.
Embeds - These are a mix of 1:1 Citric and BS made beforehand (with a binder) and normally a different colour then the whole bomb (for example a blue embed inside a bright yellow bomb) these can be as simple or as complicated as you like, the rainbow clouds are the perfect example of some fantastic embeds that take a little work.
Bloomed Baking Soda - ‘blooming’ is a term in the Bomb-making community that refers to pre colouring your baking soda. People bloom the Baking soda since it is not water-reactive (no fizzing) so you can add water-soluble colour and make the baking soda nice and bright before making the bath bomb.
Glitter- Biodegradable glitter is the most responsible choice since it goes straight into the waterways from your bathtub. Cosmetic grade glitter is also used still and is safe for skin.
Sprinkles - The lolly/sugar sprinkles that are normally used on cupcakes/baking decorations have been used as decoration. Some say this increases the chances of yeast infection since it is sugar in the water, however, the large volume of water to sugar ratio is very minute. Some people avoid them, others use them on everything, it really becomes a personal choice and for your target audience.
Botanicals - Rose petals, lavender, etc. all really pretty in a natural-looking bath bomb.
Icing - This is a term for anything added on top of the bath bomb as decoration. Some examples are bubble icing, cocoa butter icing, mica drizzle, spray bottle colours, melt and pour soap decorations, novelty toys.
Bonus information to consider -
Ideally should be around 30-35. A dehumidifier is a great investment but cheaper is a humidity gauge so you can glance and see what you are dealing with in your workspace (I picked up a digital one from Bunnings). People do successfully make bath bombs in higher humidity, but there is nothing worse than doing everything perfectly and the whole batch is ruined because of the weather.
Fragrances with high Vanilla content
Vanilla discolouration is a heartbreaking thing to discover. The perfect bomb will slowly go through a chemical discolour due to high vanilla in a smell to a brown(this can be a light tan to a dark brown or combination with your original colour). All the delicious fun ones like fudge brownies, lots of icecreams and sweet scents tend to have high vanilla. You can buy a vanilla stabiliser (1:1 ratio of fragrance) which will slow down the reaction but will not stop it completely only slow down the process. This is something important to consider when looking at fragrances.
Floating/spinning performance in bath bombs
This has to do with how light the bomb is, the shape of the bomb, the embed placement, all the fun experimentation that happens when you get a good regular recipe to use.
This is by no means an exhaustive list or a BBB (Bath Bomb Bible), just a handy guide to point you in the right direction and get started with some of the terminology and ingredients. We do have other articles also for many of these topics with more information also.
The exciting news is it's not a fixed finished project with new trends, techniques and the whole art process is always changing. Remember half the fun is the journey and those yahoo moments when things work! You can come a long way in a short time with troubleshooting and asking questions. You got this! Jump in and give it a start! We can’t wait to see what you make, we really want to cheer you on as you succeed and share in your learning