A bath bomb comes down to a pair of ingredients — citric acid and sodium bicarbonate. Without water they do not react at all, but the moment you drop the bomb into the bath the reaction starts and it begins to fizz. The rest is up to you: salts, oils, fragrances and colours. We have put together a recipe with Epsom salt and olive oil, complete with a video tutorial.
About this recipe
This recipe using Epsom salt and olive oil was prepared by our author. It is a classic bath bomb shaped in a plastic ball mould, and even a complete beginner can manage it — the whole process comes down to mixing the dry and wet ingredients and being patient while it dries.
The tutorial also includes a video in which you can watch the whole process step by step.
What is a bath bomb?
The basic ingredients of bath bombs are citric acid and sodium bicarbonate (baking soda). These ingredients do not react together without the action of water, but if we throw them into water, they react with the formation of carbon dioxide, which fizzes — and that fizz is what the bath bomb is named after. So much for the chemistry.
In cosmetics, however, it is not just about chemistry, which is why various additives are added to bath bombs that have a beneficial effect on our body. Various salts that relax the muscles, oils that hydrate the skin, dried herbs, essential oils and colourants are used as additives.
Key benefits
- Fizzing in the bath
The reaction of citric acid and baking soda in water produces carbon dioxide, which fizzes — and that fizz is what the bath bomb is named after.
- Relaxed muscles
Epsom salt in the bath relaxes the muscles; according to the author it also helps with skin diseases and heart diseases.
- Softer skin
The olive oil in the recipe softens the skin after the bath; oils in general hydrate the skin.
- Fragrance and colour to suit you
You choose the fragrance oil and the mica colourant to your own taste — you can just as well reach for dried herbs or essential oils.
- Simple to make
Just mix the dry and wet ingredients, fill the two halves of the mould and leave the bath bomb to dry for at least one day.
Product details
Key ingredients in the recipe
Below we go through the individual ingredients and the role they play in the bath bomb — from the pair that does the fizzing to the additives that turn a bath into a ritual.
Baking soda
Sodium bicarbonate is one of the two basic ingredients of bath bombs. Together with citric acid it does not react without the action of water — the reaction only starts in water, when you drop the bath bomb into the bath. In this recipe it makes up the largest share of the dry mix.
Citric acid
The other half of the fizzing pair. In water it reacts with baking soda to form carbon dioxide, which fizzes. There is exactly half as much of it in the dry mix as there is baking soda.
Epsom salt
Salts are among the classic additives in bath bombs — in the bath they relax the muscles. For this recipe the author chose Epsom salt (magnesium sulphate). According to her, salt in the bath also helps with skin diseases and heart diseases.
Starch
The dry mix also includes starch — potato or corn. The recipe uses the same amount of it as of citric acid and Epsom salt.
Olive oil
Oils in bath bombs hydrate the skin and soften it after the bath. For this recipe the author chose olive oil — you will use 2 teaspoons of it in the wet mix, together with demineralised water.
Other ingredients and equipment
Demineralised water makes up the wet mix together with the olive oil — you will use 2 teaspoons. Add it to the dry ingredients very slowly and gradually, so that the reaction does not start prematurely.
Fragrance oil gives the bath bomb its scent. Essential oils or dried herbs will serve just as well — they are among the usual additives for bath bombs.
Mica colourant colours the finished bath bomb. Colourants, along with fragrances, are the part of the recipe you can adapt entirely to your own taste.
Bath bomb mould — a plastic ball made up of two halves. These are filled with the mixture and joined together.
The recipe
The original recipe is given in grams: 112 g baking soda, 56 g citric acid, 56 g Epsom salt and 56 g starch — 280 g of dry mix in total, plus 2 teaspoons of demineralised water and 2 teaspoons of olive oil.
To make it easy to scale the batch, the shopping list below is converted to 100 g of dry mix, that is to proportions of 40% : 20% : 20% : 20%. Dose the wet ingredients, the fragrance and the colourant according to the original recipe and your own taste.
| Phase / ingredient | Amount in the recipe | Share of the dry mix |
|---|---|---|
| Dry ingredients | ||
| Baking soda | 112 g | 40,00 % |
| Citric acid | 56 g | 20,00 % |
| Epsom salt | 56 g | 20,00 % |
| Starch (potato or corn) | 56 g | 20,00 % |
| Wet ingredients | ||
| Demineralised water | 2 tsp | — |
| Olive oil | 2 tsp | — |
| Fragrance and colour | ||
| Fragrance oil | as needed | — |
| Mica colourant | as needed | — |
| Equipment | ||
| Bath bomb mould | 1 pc | — |
How to make it
- Dry mix Dry ingredients
In a bowl, mix the dry ingredients and combine them thoroughly.
- Wet mix Wet ingredients
In another bowl, mix the wet ingredients.
- Combining the mixtures
Very slowly, gradually add the wet ingredients to the dry ones and mix continuously.
- Testing the consistency
After being pressed in the palm, the mixture should hold together.
- Filling the mould
Fill the hemispheres with the mixture and join them.
- Removing the bath bomb
Tap the hemispheres with a spoon so that they separate from the finished bath bomb.
- Drying min. 1 day
Leave the bath bomb to dry for at least one day.
Video tutorial
You will learn more in the video below:
How to use it
We simply use the bath bomb by throwing it into the bath. The chemical reaction we described in the introduction takes place — fizzing. The salt relaxes our muscles, helps with skin diseases and also heart diseases, and the oil softens the skin.
Frequently asked questions about the recipe
Practical questions about the bath bomb — why it fizzes, which additives go into it, how to tell when the consistency is right and how long it has to dry.
Why does a bath bomb fizz in water?
Citric acid and sodium bicarbonate do not react together without the action of water. When you throw the bath bomb into water, they react with the formation of carbon dioxide, which fizzes — and that fizz is what the bath bomb is named after.
Which additives go into bath bombs?
Various salts that relax the muscles are used, along with oils that hydrate the skin, as well as dried herbs, essential oils and colourants. In this recipe they are Epsom salt and olive oil, topped up with fragrance oil and mica colourant.
How do I know the mixture has the right consistency?
After being pressed in the palm, the mixture should hold together. That is why you should add the wet ingredients to the dry ones very slowly and gradually, mixing as you go.
How long does a bath bomb have to dry?
Leave the finished bath bomb to dry for at least one day. To get it out of the mould, tap the hemispheres with a spoon so that they separate from the bath bomb.
Which starch should I use?
The recipe calls for potato or corn starch — use whichever you have to hand. There is 56 g of it in the batch, the same as citric acid and Epsom salt.
You will find baking soda, citric acid, Epsom salt, starch and bath bomb moulds in the Handymade range of raw materials.
