Few things land in a body of water with the satisfying “kerplunk-fizzzzz” as a bath bomb at the end of a long and harrowing day.

If you’re a parent, especially one bedeviled by young children, you’ve probably not seen the inside of an empty bathtub—let alone bathroom—for a long time. My guess is you are looking for delicate, lavender-scented toiletries the way you’re shopping for fine collectible stemware. You know, not at all.

But trust me — bath bombs are more than powdery vehicles of frivolity. Bath bombs are doers.  Bath bombs summon the filthy children to the water. They get that bedtime show on that bedtime road. They are science, they are art. They are beautifully crafted orbs. They are misshapen lumps launched into the tub. But more than anything — bath bombs are fun!

Bath bombs are doers.  Bath bombs summon the filthy children to the water.

Bath bombs are also pretty much a one-bowl project. Some care and patience are required, but the basic instructions and ingredient list are simple. If you do muddle the ingredients on your first try, don’t worry. On our first attempt, I turned around for one second and Hugo dumped all the liquid into our bowl at once. But it didn’t matter! He still loved the process (and lumpy outcome), and he had a blast that night in the tub. Bath bomb-making is seriously your game to lose, folks.

Now to the main event...

You'll Need:

• 2 cups baking soda
• 1 cup corn starch
• 1 cup citric acid
• 1 cup Epsom salt (the finer the better, but don’t fuss over this)
• 5 tbsp vegetable oil (olive oil, coconut oil, etc.)
• 4 tsp water (to start)
• 1–2 tsp essential oil (lavendar is nice)
• food coloring (optional)
• small water-safe trinkets or candy dragées for eyes (optional)

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Step One

If you’re an apron person, don one now. If you wear nail polish, are making gifts, or if anyone has any cuts or scrapes (citric acid!), you may wish to wear gloves. 

Step Two

Add baking soda and cornstarch to a big bowl, passing them each through the sieve to break up any clumps. Measure and add the citric acid and Epsom salt to the bowl. Mix these four ingredients VERY well with a spoon, then use a whisk. 

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Step Three

Combine your vegetable oil and fragrance in a smaller bowl, then add this to your dry ingredients. Use your spatula to get every last drop of oil. If there is any fizzing, whisk the mixture vigorously to stop the reaction.

Step Four

Add 4 – 8 drops of food colouring to your water (if using). Add half of your water/colour solution SLOWLY to the large bowl, whisking vigorously to dampen the reaction. Don’t be afraid to use your hands to break up any small lumps. Whisk the mixture until you have a fine crumb. The mix will look impossibly dry, but squeeze it with your hands to see if it holds a shape. If it’s still too dry, add a few more drops of your coloured water. Mix well. Repeat this process until the mixture JUST holds a decent shape. If you add too much water, your mixture will feel spongy and start to expand in your molds, but again — this is not the end of things. Kids like weird lumps, I promise.

Step Five

Scoop your powder into molds, muffin tins or cookie cutters and press very firmly. Take your time and make sure you’ve packed each section or mold well. If you’d like a clean edge, run the backside of a knife over the top of your molds so you have a clean line. If you’re using cookie cutters, fill to no more than ¾ the height of the cutter UNLESS you’re planning to give the bath bomb as a gift in the cookie cutter (see below!).

Step Six

Leave your bombs to dry in a warmish area overnight (big ones could take a bit longer), then invert your mold or muffin tin onto a soft towel. Most of your bombs will probably slide out, but if not, tap the bottom or sides with a metal spoon until you hear them drop. Let them dry in the open air for another day or so. That's it! If your bath bombs are gifts, or if you would like a finer edge, you can use a kitchen rasp and/or fine sandpaper to clean up the bottoms or edges. Store in glass containers (metal and plastic containers are not advised).

Makes approx. 12 medium-sized muffin tin bath bombs.

WILLY WONKA’S GOLDEN TICKET? If you’re using muffin tins for your bath bombs, it’s really easy to hide fun little things in the bombs. A nickel could mean an extra book at bedtime, a tin-foil heart could mean a 2-song dance party — and maybe a red marble could mean clean-up your room! Work it, my parents.