How To Make Bath Bombs ~ One Recipe For Every Kind of Bath Bomb!

Natural bath bombs are a great way to relax and pamper yourself at home. They can make your bath water fizzy and fragrant, while also nourishing and soothing your skin. But, did you know that you can make your own bath bombs with natural ingredients that you may already have in your kitchen or garden? In this blog post, we'll show you one versatile recipe for luxuriant homemade bath bombs that are fun, affordable, and eco-friendly.  Making bath bombs is also a fun and easy project with the kids as they don't involve heating or handling harsh chemicals.

How to Make Bath Bombs Recipe

Our home made bath bombs are extra special as they only use safe, earth friendly ingredients. They do not contain any artificial colours, perfumes, or sodium laureth sulphate like many commercial bath bombs, such as Lush bath bombs. 

Whether you want to create a floral, citrus, herbal, black charcoal, or even a chocolate bath bomb, we have the perfect recipe for you. So grab your mixing bowl and let's get started!

Why do bath bombs fizz?

Firstly, let's understand the science of how a bath bomb recipe works. Bath bombs fizz because they contain a secret ingredient: magic! Just kidding, it's actually science. Bath bombs are made of two main components: bi carb soda (also known as baking soda or sodium bicarbonate) and citric acid. When these two substances are dry, they don't react with each other. But when you drop them in water, they start to dissolve and release carbon dioxide gas. This gas forms bubbles that make the water look fizzy and feel ticklish on your skin. The more bath bombs you use, the more bubbles you get. It's like having your own personal spa in your bathtub!

What are the ingredients in homemade bath bombs?

No matter the scent or look you want, with this one simple recipe, you can make countless variations of bath bombs at home, saving you a lot of money.  These bath bombs make wonderful personalised handmade gifts at a fraction of the cost of store-bought bombs.

1. Bi-carb soda: reacts with the citric acid to create the fizz. 

2. Citric acid: Citric Acid is an alpha-hydroxy acid that stimulates collagen production and promotes regrowth. It also provides the "fizz" in this bath bomb. 

3. Epsom Salt:  This magnesium-based salt can be added for additional muscle relaxation and to promote sleep. 

4. Cornstarch, coconut milk powder, or kaolin white clay: gives the bath bomb a 'silky' feel. 

5. Oil: oil binds the ingredients and leaves your skin feeling soft, soothed and moisturised. Choose from castor oilfractionated coconut oiljojoba oil, or other light oil such as sunflower or grapeseed oil.

6. Scents, herbs, petals and powders: here's where you get creative and customise your bath bomb with a combination of essential oils, herbs and petals for their unique properties, and even spice it up with cacao or activated charcoal.  At Biome, you can find a huge range of essential oils for all your needs. 

7. Colour: all brightly coloured commercial bath bombs use artificial colours as it is not possible to get those colours from nature.  We don't recommend soaking in artificial colouring!  Plant powders and clay are the best way to naturally colour bath bombs. Try powders like turmeric for yellow, blueberry for blue, spirulina or matcha for green, pink dragonfruit or beetroot powder for pink, or red or pink clays, charcoal for black, and cacao for chocolate brown.

Note: there is no water in the recipe!  Try to avoid making bath bombs on a hot, humid day as the moisture in the air may cause the bath bombs to expand and fizz prematurely.

All of our bath bombs are suitable for sensitive skin, but be sure to avoid any essential oils that you know irritate your skin.

Bath bomb recipe

To get you started, here are five variations for how to make bath bombs.  With each bath bomb you will use the same base ingredients and method, but create variations with the essential oils, petals, spices, herbs and powders.

All the DIY bath bomb recipes here make enough for approximately five round 100g bath bombs.

You can use a bath bomb mould, but all of ours in the photos here have been hand rolled, which works just as well and is a bit more fun.

1. Moisturising Rose Bath Bomb

How to make rose bath bombs

These DIY rose scented bath bombs make a wonderful gift, or spend a lovely afternoon making them with someone special! 


  • 1 cup bi-carb soda
  • ½ cup citric acid
  • ½ cup cornstarch
  • ½ cup epsom salts
  • Up to ¼ cup castor oil or other light oil
  • 1 teaspoon vitamin E oil (optional)
  • 2 tablespoons dried rose petals (1 tablespoon will be infused in the castor oil and the remaining tablespoon is for decorating)
  • 6 drops rose geranium essential oil
  • 6 drops lavender essential oil
  • 6 drops grapefruit essential oil
  • 6 drops mandarin essential oil

How to make Infused Castor Oil

For addition scent and beneficial properties, you can infuse the oil with various herbs and petals.  For example, soak one tablespoon of dried rose petals with castor oil (or alternative oil) for a few hours or overnight. Once the dried rose petals have been infused, strain the oil through a garni bag, muslin, or a sieve into a cup and set aside. You may need to squeeze the rose petals or herbs to get more of the oil out.

Method (for all bath bomb recipes):

  1. In a large mixing bowl, add all the dry ingredients (bi-carb, cornstarch, Epsom salt, citric acid, coconut milk, clay, etc). Mix together thoroughly with a whisk.
  2. Add the essential oils and vitamin E (if using).
  3. Stir the mixture, and while stirring, gradually add in half the oils until you have a crumbly mixture that still holds together well.  Use your hands to bring it together.
  4. It should start to resemble wet sand or moist cookie dough. If it seems too dry, add a little more oil and repeat the mixing process. Don't use too much oil or the mixture may start to expand and fizz, ruining your batch. 
Hand mould:
  1. Divide the mixture into 5 equal portions.
  2. Gently roll each portion into a ball without pressing too hard. This will take a little patience, but slowly you'll start to see the ball form and hold together.
  3. Once you have 5 balls, roll each of them in the remaining rose petals. You might like to grind the petals down using a mortar and pestle to help them stick more easily to the bath bomb.
  4. Place the bath bombs on top of a soft towel and let them dry overnight. It's best to let them dry for at least another 24 hours after that to increase their fizzy power.
Bath bomb mould:
  1. Divide your mixture into the moulds and pack down lightly.
  2. Press some rose petals into the tops of them for decoration. You might like to grind them down using a mortar and pestle, as mentioned above.
  3. Let your DIY bath bombs set overnight in the mould.
  4. The following day, gently remove the bath bombs from the mould, and let them air dry for 24 hours.

With the petals and red colour these are great bath bombs for kids

2. Festive Chocolate Bath Bomb

Festive Christmas bath bomb recipe

Here's how to make bath bombs that smell just like Christmas in Australia! Combining traditional festive spices with a hint of classic Australian lemon myrtle, soothing Epsom salts and moisturising castor oil, our DIY festive bath bombs will help you wind down and get straight into that Christmas spirit. Use these DIY bath bombs for yourself, or gift to friends and family. 


  • 1 cup bi-carb soda
  • ½ cup citric acid
  • ½ cup cornstarch
  • ½ cup epsom salts
  • Up to ¼ cup castor oil or other light oil
  • 1 teaspoon vitamin E oil (optional)
  • 3 tbsp cacao powder
  • 1 tsp ground cinnamon
  • ½ tsp ground clove
  • ½ tsp ground nutmeg
  • ¼ tsp ground ginger
  • ¼ tsp ground allspice
  • 12 drops orange essential oil
  • 8 drops lemon myrtle essential oil
  • 3 drops cinnamon essential oil
  • 3 drops clove essential oil
  • 3 drops nutmeg essential oil
  • 3 drops ginger essential oil

For an optional decoration: mix together 1 tsp sparkly mica and 1 tsp Epsom salt and sprinkle on top while wet.


Follow the method under number 1. 

3. Citrus Burst Bath Bomb

Citrus Burst Bath Bomb Recipe

With a beautiful combination of uplifting essential oils, healing calendula petals and moisturising castor oil, you'll want to learn how to make this lovely bath bomb. 


  • 1 cup bi-carb soda
  • ½ cup citric acid
  • ½ cup cornstarch
  • ½ cup epsom salts
  • Up to ¼ cup castor oil or other light oil
  • 1 teaspoon vitamin E oil (optional)
  • 3 tablespoons dried calendula petals (for infusing in the oil and decoration)
  • 6 drops grapefruit essential oil
  • 6 drops orange essential oil
  • 4 drops bergamot essential oil
  • 4 drops lemongrass essential oil
  • 4 drops ginger essential oil


Follow the method under number 1. 


4. Green Tea & Epsom Salt Bath Bomb

how to make green tea epsom salt bath bombs

A beautifully-scented bath bomb that is great for your skin and well being. Essential oils help calm your mind, while Epsom salts relaxes and green tea detoxifies and soothes.  By now, we think you are seeing the easy pattern for how to make bath bombs!


  • 1 cup bi-carb soda
  • ½ cup citric acid
  • ½ cup cornstarch
  • ½ cup epsom salts
  • Up to ¼ cup castor oil or other light oil
  • 1 teaspoon vitamin E oil (optional)
  • 2 tbsp dried Green Tea  (for infusing in the oil and decoration) or matcha green tea powder
  • 6 drops Lemon essential oil
  • 6 drops Lemongrass essential oil
  • 6 drops Ginger essential oil


Follow the method under number 1. 

5. Black Bath Bomb with Activated Charcoal

How to make black bath bombs with activated charcoal

With our black bath bomb recipe you can take your love of activated charcoal to a whole new level. These unique little bath bombs contain detoxifying activated charcoal, nourishing castor oil and soothing epsom salts, leaving you feeling cleansed and relaxed. It is great for those who have oily or combination skin, acne and blemish prone skin, or those who love something a little bit different!

While your bath water will turn black, it won't stain. Just be sure to clean your bath down as soon as you are done.


  • 1 cup bi-carb soda
  • ½ cup citric acid
  • ½ cup cornstarch
  • ½ cup epsom salts
  • Up to ¼ cup castor oil or other light oil
  • 1 teaspoon vitamin E oil (optional)
  • 1 tablespoon activated charcoal
  • 6 drops rosemary essential oil
  • 6 drops thyme essential oil
  • 6 drops lavender essential oil
  • 6 drops sage essential oil


Follow the method under number 1. 


How to Store Bath Bombs

If you're a fan of fizzy, fragrant and lush bath bombs, you don't want your precious bombs to go off prematurely or lose their potency. Here are some tips on how to store your bath bombs.

  • Keep bath bombs away from moisture. Water is the enemy of bath bombs, as it triggers the chemical reaction that makes them fizz. If water gets at them, they might start to crumble, crack or lose their scent. To prevent this, store your bath bombs in an airtight glass container in cool, dark place away from humidity or steam.
  • Keep bath bombs separate. Different bath bombs might have different ingredients, scents or colors that could affect each other if stored together. To avoid any unwanted reactions or mixing, store your bath bombs individually or in separate compartments. 

How to Use Your Homemade Bath Bombs 

Now that you know how to make bath bombs, it's time to enjoy! Run a warm bath and drop in one bath bomb. It should fizz and release a beautiful relaxing aroma.

Use bath bombs within six months. Bath bombs are best used when they are fresh and potent. Over time, they might lose their fizziness or scent due to exposure to air or moisture. 

Always wash down your bath tub as soon as you're done to prevent any discolouration or scum build up.

CAUTION: Please be very careful of slipping and falling.  Due to the oils in bath bombs, your bath may become slippery.


DIY Recipe for Homemade Shower Bombs

Shop all our ready made natural bath bombs

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