How to Make Bath Bombs at Home

• Sodium bicarbonate (baking soda): the base, and the largest component by volume
• Citric acid: reacts with the sodium bicarbonate to create the fizzing effect
• Foaming bath butter base or oil: binds the mixture and adds a moisturizing, skin-conditioning finish
• Skin-safe fragrance oil: for scent
• Mica powder: optional, for color
• Witch hazel or a light spray of water/alcohol: just enough to bind the mixture without triggering the fizzing reaction early

2 parts sodium bicarbonate : 1 part citric acid

1. Sift the sodium bicarbonate and citric acid together into a large bowl to remove clumps
2. In a separate small bowl, combine your oil/butter base with fragrance oil and color
3. Slowly drizzle the wet mixture into the dry mixture while whisking continuously
4. Add witch hazel or water a few spritzes at a time, mixing between each spritz, until the mixture holds together when pressed (like damp sand)
5. Pack the mixture firmly into a mold, pressing both halves together and holding for a few seconds
6. Let cure in the mold for a few minutes before gently unmolding
7. Allow finished bombs to air-dry for 24–48 hours before use or packaging

The mixture starts fizzing before molding

This means moisture was added too quickly or in excess. Add liquid in small spritzes, mixing thoroughly between each one, rather than pouring it in.

The bath bomb crumbles when unmolding

The mixture likely needed more moisture or oil to bind properly, or wasn't packed firmly enough into the mold.

The bath bomb expands or cracks after molding

This usually happens when there's too much moisture in the mix, causing the reaction to continue slowly inside the mold. Reduce liquid slightly next batch.

Why do my bath bombs fizz before I even use them?

This happens when too much moisture is introduced during mixing, triggering the acid-base reaction early. Add liquid slowly and in small amounts.

How long do bath bombs need to dry before packaging?

At least 24–48 hours in a dry environment, to ensure they're fully hardened and won't crumble or continue reacting once sealed.

Can I use food coloring instead of mica powder?

Liquid food coloring can work but may stain the tub or skin more than cosmetic-grade mica powder, which is formulated for this kind of use.

Why did my bath bomb turn out too soft?

Too much oil or liquid relative to the dry ingredients is the most common cause. Reduce the liquid slightly and ensure the mixture feels like damp sand, not wet paste, before molding.