Today we're going back to basics and will talk about how to make homemade bath bombs. Making bath bombs is fun, easy and you can really get creative with it.
My kids absolutely love bath bombs and they make for great gifts. To me it is so much fun to see the bath bomb fizzing away in the tub. It simply gives your bath time this special sparkle and excitement while at the same time delivering gorgeous scents and skin loving goodness. 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 very basic DIY bath bomb recipe. It doesn't require a ton of ingredients and they're easy to source at your local supermarket and health food store.
Jump to:
- What is a Bath Bomb and What do Bath Bombs do?
- Ingredients (makes 2 big 4 oz bath bombs):
- Equipment:
- How to Make Bath Bombs at Home
- How to Use a Bath Bomb
- Can You Make Bath Bombs without Citric Acid?
- What does Cornstarch do in Bath Bombs?
- Can I use Food Coloring to Color my Bath Bombs?
- Do I have to Use a Special Bath Bomb Mold?
- Tips for Making Bath Bombs
- Troubleshooting
- Why did my bath bomb crack? Why did my bath bomb crumble?
- Why did my bath bomb halves not stick together?
What is a Bath Bomb and What do Bath Bombs do?
Bath bombs are made up of two key ingredients: baking soda and citric acid. Mixing both together will set off a fizzing reaction when immersed in water. Baking soda on it's 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, salts etc.) to a bath in a fun way.
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Ingredients (makes 2 big 4 oz bath bombs):
- 1 cup baking soda
- ½ cup citric acid
- ¼ cup cornstarch
- 1 tablespoon of grapeseed oil (you an use melted coconut oil or canola oil instead)
- ½ tablespoon of polysorbate 80 (optional, will help keep your tub slick free)
- 15 - 20 drops of lavender essential oil
- blue and red food coloring
- witch hazel
Equipment:
- one medium sized and one smaller bowl for mixing
- a wire whisk
- a spray bottle for the witch hazel
- bath bomb molds (I used the 2.6 inch size)
- a shot glass
- gloves (optional)
How to Make Bath Bombs at Home
- Combine baking soda, citric acid and cornstarch. Make sure there are no clumps by either putting your mixture through a sifter or by working them out with your hands
- Melt and add the coconut oil; Combine well
- Add polysorbate 80 and essential oil; Combine
- In a shot glass combine 12 drops of blue food coloring with 12 drops of red food coloring; Stir
- While constantly whisking add food coloring to the mixture little by little
- Incorporate the food coloring thoroughly by rubbing the mixture in between the palm of your hands until the color is evenly dispersed
- Spritz with witch hazel until the mixture reaches the desired consistency, test by squeezing mixture in your fist and see if it's firm enough to hold it's shape and won't crumble if you tap it gently with your finger
- Fill both halves with the mixture and pile as much as you can on top
- Firmly squeeze both halves together; Don't twist!
- Gently release one half, then flip the bath bombs back into that half and release the other half (if you're having trouble getting the bath bomb out, use a spoon and gently tap on the mold). Release by first twisting, carefully lifting the mold
- Set the bath bomb aside while still sitting in one half of the bath bomb mold
- Let set overnight and unmold
How to Use a Bath Bomb
Fill your tub, drop in your bath bomb and watch it fizz. When it's done fizzing you might want to move the water around a little bit with your hand. Get in the tub and enjoy.
The bath bombs we're making today are pretty big, so one bath bomb per bath would be enough. If you are using smaller bath bombs or have a larger tub you might want to use two.
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 to get out safely so nobody slips. If you wish to counteract the slickness hazard you can try using sunflower lecithin or polysorbate 80, these will help disperse the oil evenly in the water without sticking to the side and bottom of 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. It's great - I use it all the time!
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 together are a very reactive bunch and will fizz very quickly and vigorously.
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. Ideally you want to use gel food coloring since it doesn't contain any water. If the only thing you have on hand is regular water based food coloring it will work as well if you either:
a) whisk your mix while adding the color (shown in video) or
b) mix the color only into your baking soda mix and wait to add the citric acid once the color is fully incorporated.
Do I have to Use a Special Bath Bomb Mold?
No, one of my favorite "molds" is a stainless steal 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 where you would leave the mixture in the mold to dry overnight.
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). Boy, have I learned this the hard way. If you ever want to see a bath bomb expand and expand right after it was made and transform into a droopy mess - then try making bath bombs in 80% humidity weather.
- 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 it's 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 not hold it's shape once unmolded. A mixture that's too dry will crack or crumble upon unmolding. There's a sweet spot you need to find between the two.
- 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". Yes, it doesn't sound pretty and it isn't. It looks like the bath bomb has little protruding growths on it.
- If you're using water based food coloring use a whisk to quickly work in the color. If you have a big blob of color just sitting in your mixture it will start to fizz and that's what we're trying to prevent.
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 to only 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?
This is so frustrating isn't it? Creating the perfect round bath bomb is like the holy grail of bath bomb making, so don't beat yourself up 😉
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 full 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
Until next time. Happy Tinkering!
Looking for more fun bath bomb recipes? Try:
Aimee
Hi there
what is the witch hazel for? can I use a witch hazel and rose water mix?
Celine
Hi Aimee,
great question! Witch hazel is used to achieve the wet sand consistency of the bath bomb mix before you mold it. Depending on your climate you might not even need it, if the recipe contains enough liquid oils, butter and essential oils and you live in a humid climate. I like to use witch hazel or 90% rubbing alcohol since these don't set off the fizzing reaction when added to the mix. You can use rose water sparingly, too much will cause your mixture to fizz. Happy Tinkering 🙂
Ashley
I have witch hazel mixed with rose water, can I use that? Not just the rose water, but the witch hazel is mixed with the rose water already
Celine
Yes you can sparingly in a spray bottle while you whisk the mixture. Happy Tinkering!
Loan
My bomb is not fizzy. I dont know the reason. Could you please tell me more?
Celine
Hi Loan, two things come to mind. Either your baking soda or citric acid was past its expiration date/ exposed to humidity or your finished bath bomb wasn’t properly stored and was exposed to humidity. Hope that helps. happy Tinkering 😃
marie
hi, is it possible you could pint me the direction of the mould you used in the video please? it isn't the one linked x
Celine
Hi Marie, it’s the stainless steal one from Brambleberry https://www.brambleberry.com/shop-by-product/molds/stainless-steel-bath-bomb-mold%2C-2-pieces/V000512.html
Molly
Hello, I'm planning to make these with my Girl Scouts next week and I think they will love it! If we wanted to add epsom salts to the mix, when would we do that? Thanks!
Celine
Hi Molly, that's a fun idea. you can add Epsom salts right in the beginning. May I suggest you use plastic bath bomb molds or Christmas ornaments if you have a group. That way they can take them home and take out of the mold the next day otherwise you would have to keep them somewhere over night. For younger kids it might be easiest to use a silicone mold similar to an ice cube tray where they can simply push the mixture into each cavity. Happy Tinkering 🙂
Kalli
If I were to add Epsom salt, how much would I add? Do I need to change any of the other amounts to make it the right consistency?
Celine
Hi Kalli, you can replace the cornstarch with Epsom salt.
Lorelei
How many bath bombs does this recipe yield?
Celine
two big sized bath bomb or 4 small bath bombs
Hazel
can I use coconut oil from the grocery store?
Celine
Absolutely
Dawn
I see that many people use salt in their bath bomb recipes. I was wondering why you don't.
Celine
Hi Dawn, I n order to make bath bombs fizz you really only need 3 ingredients: baking soda, citric acid and a form of liquid (witch hazel or water) in order to hold them together. Some people use salt to make them harder or add epsom salt for the added benefit. I have a bath bomb recipe on here with sea salt and one with epsom salt.
Minerva
If I use sunflower lecithin instead of Polysorbate 80, how much should I use? should I use more wet ingredients since it's dry instead of wet like Polysorbate 80?
Celine
I wouuld use 2 tsp, Amazon now sells one that is liquid. If you're using the dry form, use a little more witch hazel to get the consistency right.