DIY Colour Powder Bath Bombs @HOME!

DIY Colour Powder Bath Bombs @HOME!

Everyone loves making a fun fizzing colourful bath bomb, ideal for your own use or as a gift. Purchase the colour powder on our website and buy the remaining ingredients from the supermarket.

Here’s our tried and tested recipe that we are happy to offer for FREE. It makes approx 4 bath bombs; simply multiply the amounts to make a lot more!


  • 1/8 cup of coloured powder (16grams) – we have red, blue, green, orange, purple, yellow, pink in 100gram bags
  • 1/4 cup of baking soda
  • 1/8 cup of citric acid (loses potency over time, buy new or make sure it’s been stored in airtight container)
  • 1/8 cup of epsom salt
  • 1/2 tsp of water
  • 1 tsp of oil (i.e. caster)
  • A few drops of essential oil (i.e. lavender, vanilla)
  • Moulds (refer to FAQs)


  1. Combine baking soda, citric acid, epsom salt and coloured powder in a large bowl and mix well until combined. Use fingers to ensure any clumps of powder are broken down properly.
  2. Gradually add the caster oil and essential oil (if desired) to the dry ingredients a few drops at a time. Mix well with hands (wear gloves if you have sensitive skin). Add water last, as it creates a reaction. It is important to stir water in quickly. Avoid allowing the mixture to fizz.
  3. Mixture should slightly hold together when squeezed. You may need to add slightly more oil if it hasn’t achieved this consistency yet.
  4. Push mixture into moulds. Press in firmly. Seal to make air tight.
  5. Leave for 24-48hrs or until hardened. It is important that your bath bombs are sealed or covered to keep the air out as much as possible.
  6. When dry, remove and store in airtight container, jar or bag. If you remove bath bomb too early, it will crumble. We live in a humid climate in Queensland and choose to wrap each bath bomb in plastic wrap or put in a sandwich bag to protect them from excess moisture.

TIP: we suggest making batches of different colours and combining – but not mixing – 2 or 3 colours in the mould

How to use

  • Drop into a luke warm bath and watch the water fizz as the bath bomb dissolves and the water turns colour.
  • If you’ve put essential oils in your bath bomb it will also smell amazing.
  • The oil will moisturise skin and make it silky smooth.
  • Enjoy and relax. The colour should not stain the bath tub (although there are lots of different surfaces on baths so we can’t guarantee that it won’t stain all of them)

Frequently Asked Questions (FAQs)

How long do bath bombs last?

If not stored properly, bath bombs should be used within 2 weeks. Some have stored their bath bombs longer by wrapping them in plastic and putting them in airtight containers. Citric acid loses its potency within 6 months of exposing it to air.

Where do I find bath bomb moulds?

Two-part moulds made of plastic, silicone or aluminium can be purchased online or from a local craft shop. Ball shaped moulds are most common (i.e. round cupcake moulds) Alternatively, to reduce costs, you can re-used half-moon dumpling or round chocolate trays, as well as small cupcake/muffin trays. It is important when using a tray type mould, that the tops of the bath bombs are covered, to reduce reactivity with humid air.

How do I dry bath bombs?

Natural air drying indoors takes 24-48 hours. This process can be sped up by putting bath bombs in a fridge for about an hour before removing them from mould.

If you are using a baking tray for your mould, we have seen that others dry in the an oven (preheat oven to 170F, turn off, insert trays, close door), but haven’t tried this ourselves.

Why are my bath bombs crumbly and fall apart?

Batches with too little liquid ingredients will cause bombs to not hold shape. It is important that you use just enough liquid to form each bomb.

Why didn’t my bath bombs fizzle?

There are a few reasons this happens:

    1. Citric acid is no longer active (sitting exposed to air for weeks/months). Test ingredients with water to ensure fizzle in advance of activity to avoid disappointment.
    2. Too much water or oil was added to recipe. This can be seen while making bombs as the mixture will fizzle in bowl or moulds.
    3. Bombs were stored uncovered or unwrapped for an extended period of time before use.
    4. Too much coloured powder was added to bomb mixture.
    5. Bombs were dropped into cold water instead of warm water.

What is the basic science behind the bath bomb?

The baking soda is a weak base and the citric acid is a weak acid. This creates an acid-base reaction which creates carbon dioxide bubbles when added to water. The coloured powder acts as a filler to control this reaction.