How to Make Homemade Bath Bombs

Learn to make easy DIY bath bombs using a simple recipe and natural ingredients. They will come out perfectly every time - I promise! 

My kids absolutely love bath bombs. Seeing them fizzing away in the tub brings them so much joy. Bath bombs simply give your bath time this special sparkle and excitement while at the same time delivering gorgeous scents and skin-loving goodness. If you make your own bath bombs, you can save a lot of money compared to store-bought. Aaand, they make a great gift. What's not to like?

I've experimented with different ingredients and techniques over the years. In this article, I will show you how to make bath bombs using a simple bath bomb recipe without a ton of ingredients. But the secret to creating perfectly round, crumble-free bath bombs is to let them dry in the mold. The molds I'm using are great for that, plus they double as the perfect packaging.

What are bath bombs, and what do they do?

Bath bombs comprise two main ingredients: baking soda and citric acid. Mixing both together will set off a fizzing reaction when immersed in water. Baking soda on its own adds some health benefits to the bath water, but typically, a bath bomb is used to deliver additional skin-loving ingredients (like essential oils, oils, bath salts, milk powder, etc.) to a bath in a fun way.

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How to Use a Bath Bomb

Fill your tub, drop in 1-2 bath bombs, and watch them fizz. When it's done fizzing, you might want to move the water around a little bit with your hand. Get in the tub, soak and relax after a long day of work.

Caution: Bath bomb recipes that contain oil or butters can leave a slick film on the bottom of your tub. Exit the tub carefully and help your kids get out safely. If you wish to counteract the slipperiness, add polysorbate 80, it will help disperse the oil mixture evenly in the water without sticking to the tub.

Can You Make Bath Bombs without Citric Acid?

Can you make bath bombs without citric acid?  The short answer: Yes, but it won't fizz as much! My friends over at CountryHillCottage have a great recipe you can try.

If you're concerned about citric acid being made from genetically modified fruit, I suggest you use non-GMO citric acid that you can find here. 

What does Cornstarch do in Bath Bombs?

Cornstarch is used in many homemade bath bomb recipes as "buffer" if you will. Citric acid and baking soda are very reactive and will fizz and create a chemical reaction quickly when exposed to moisture. 

By adding cornstarch to the mix the citric acid and baking soda don't sit quite as closely together. Therefore, your bath bomb will fizz longer and more moderate. Also, you can reduce the risk of your bath bomb fizzing up before it hits your bath (when exposed to moisture, etc.).

Can I use Food Coloring to Color my Bath Bombs?

Yes, you can. Gel food coloring will give you a stronger color but is tougher to incorporate. Regular food coloring will work as well, but it might set off the fizzing reaction due to its water content.

Do I have to Use a Special Bath Bomb Mold?

No, one of my favorite "molds" is a stainless steel ¼ cup measuring up. I used it to make these Lime Coconut Milk Bath Bombs. You can also use an ice cube tray or a silicone baking mold.

Tips for Making Bath Bombs

• Avoid making bath bombs when the air is very humid (e.g. it's raining or has rained for the last few days). The mixture will absorb the moisture in the air and never really set up.
• Pay close attention to the consistency of your batter before putting it in the mold. It takes some practice to be able to notice the right consistency. I typically squeeze the mixture and see if it holds its shape. If it does I give it a little tap with my finger so I can gauge the firmness. If not firm enough, I will add a couple more spritzes of witch hazel. A mixture that's too wet will not harden enough and will not hold its shape once unmolded. A mixture that's too dry will crack or crumble upon unmolding. 
• Sift your dry ingredients or really try to work out any clumps with your fingers. If there are clumps in your mixture, you run the chance that your bath bombs develop "warts." It looks like the bath bomb has little protruding growths on it.

For Humid Weather

• Omit any type of salts (epsom salt, sea salt, etc.) from your bath bomb recipe. Salts will attract moisture and mess with your final product.
• Keep in mind that your mixture might already have enough moisture from the humidity in the air before adding any witch hazel or isopropyl alcohol. Do your squeeze test and decide if you need to add any more moisture.
• Use a plastic mold or Christmas ornament that interlocks. I've had good results with this type of mold as I find it creates a tight enough seal to keep any moisture out.
• You could look into "baking" bath bombs at 170º F in the oven for a couple of hours, then turn it off and let the bath bombs dry in there overnight.

Troubleshooting

Why did my bath bomb crack? Why did my bath bomb crumble?

Oftentimes, you'll see cracks or crumbly sides after the bath bomb has been set out to dry. Most likely your mixture was too dry when you molded the bath bomb. Try using a little bit more liquid (witch hazel or isopropyl alcohol) or oil next time. Remember only to add a little at a time and check the consistency often. Too much moisture will make your bath bomb too soft.

Why did my bath bomb halves not stick together?

There can be several reasons for separated bath bomb halves:

• Your mixture is too dry, and the halves can't stick together properly
• You didn't fill your mold enough before pressing the halves together. Remember to really mount the mixture as high as you can.
• You twisted the two spheres and thereby separated the halves from each other
• Try the instructions in this recipe and leave the bath bomb drying in the closed mold overnight

Until next time. Happy Tinkering!

Looking for more fun bath bomb recipes? Try:

• Oatmeal Bath Bombs for Sensitive Skin
• Easy Bath Bombs for Kids
• Snowman Bath Bombs