Don’t you just love the fizzing, sparkling and bubbling of a gorgeous bath bomb? For those who have been hiding under a rock for the last few years, a bath bomb is a ball of fizzing scented goodness which releases scent and colour into the bath.
There are many things you can put into a bath bomb but the two main ingredients are Sodium Bicarbonate (Baking Soda) and Citric Acid. Both are easily available at your local grocery or oriental food store. Or you can order them from one of the many soap making online shops.
The other main ingredients are fragrance and colour. Additional goodies could be oils, clays, glitter, botanicals, salt grains, oats, aloe powder, honey powder, seaweed or herbs. As you can see the potential is almost endless.
A word about colour before we start. You 
should use a water-soluble colour for your bath bombs. Those that are soluble in oil won’t work as they will not disperse in the bath water. The best are the kind that you can use in melt and pour soap. Pigments used in cold process soap also can be used but they must be used in very small amounts or they can stain the bathtub quite badly. I have only used enough to give a light pink tint to my bath bombs. Food colours work as well.
You will need a mould to put your bath bomb in. The most recognisable mould is the round two part mould which makes a spherical bath bomb. You can easily buy these online. But you can use anything you want. I often use silicone moulds for baking although you do have to be careful with these. They can distort in shape when you are packing your mixture in tightly. I have used muffin trays, cupcake silicone moulds (both with and without the cupcake liner) and the little cardboard cupcake or mini loaf cases are perfect. Have a look around the house and see what you have to hand.
So how do we make them?
Here is a basic recipe which you can customise yourself.
400g Bicarbonate of Soda
200g of Citric acid
6g of fragrance (1%)
A tiny drop of colour.
You will also need a spray bottle with some water in (or you can use witch hazel if you prefer)
Place your Bicarbonate of Soda and Citric acid in a large bowl. A large bowl used for baking is ideal. Mix the dry ingredients together thoroughly. You can use a spoon, spatula or your hand.
Add a few drops of your colour and mix. Then add all of your fragrance. Stir until they are all well mixed.
This is the tricky part. Start spraying your water in with one hand while mixing with the other. Use only a very small amount to begin with. Keep stirring and adding the water until the mixture looks like damp sand.
You know the type that is perfect for building a sandcastle? It should hold together when squeezed into a ball but not be wet. If it gets too wet, the mixture will start to react and fizz and bubble and your mixture will be ruined. You can squeeze the mixture in your hand. It is ready if it holds together and doesn’t crumble with slight pressure.
Once you ha
ve the correct consistency, it is time to press into your mould. You need to pack it in quite tightly so that it all holds together. If you don’t it will have too many air pockets and will crumble when it is removed from the mould.
I recommend l
eaving the bath bomb in the mould for a few hours or even overnight. It is possible to remove them from the mould but unless you are perfect at getting the wetness right your bath bomb may flatten or go out of shape. Best to leave it in there.
The best idea is to make these bath bombs only a few at a time. If you make a big batch of mixture it can start to harden in the bowl before you can get it all in the moulds.
Extra additions (to the dry mixture)
1 tablespoon of any oil you like or butters that have been melted and cooled a bit (too much heat will cause it to fizz)
A tablespoon of rose petals, lavender buds, calendula or any other botanical that takes your fancy (but remember that although they look great, they are messy in the bath).
A tablespoon of powdered seaweed, honey, aloe or any other powder you like
A tablespoon of oatmeal
A tablespoon of clay eg bentonite or French green clay. This makes a very hard bath bomb too
You could add a tablespoon of Epsom salts, dead sea salts, or sea salt. Himalayan pink sea salt is very pretty in a bath bomb too.
If you want your bath bomb to produce bubbles that last you can add a tablespoon of SLS or SLSA (do remember to wear your mask for this)
And of course you can add a sprinkle of glitter. You can mix it in or you could sprinkle it on the surface of the mould to make it glittery on the outside!
The most tricky part of the process is getting the wetness right. If it is too dry your bath bomb may crumble when you take it out of the mould. If you don’t pack it in enough it may be crumbly or split down the seam when you take it out of the mould. If it was too wet then it might stick in the mould or if you have added much too much water it will fizz right up before you put it in the mould.
Here is what happens when your bath bomb is too wet!
And this is what they look like when they go right!
So good luck with making the bath bombs. If you would like to share your version of this recipe we would love to see them.
