Categories: Bath Bomb Recipes

Make a Bath Bomb float like LUSH

It’s the hardest thing to figure out for a new bath bomb maker…how do you make a bath bomb float like LUSH?  Why don’t any of the online recipes make bath bombs float like LUSH?

Two ingredients Make them Float!

The first one is called SLSA (Sodium Lauryl Sulfoacetate), and you may have it on hand if you are a frequent bath bomb maker.

Get coarse SLSA at Amazon

The other ingredient is Coco Betaine (Cocomidopropyl Betaine).  Both of these ingredients are natural bubbling agents made from coconuts.

Buy Coco Betaine at Amazon

Coco Betaine is very inexpensive and this 500g bottle from Amazon Prime will last you a long time.  In addition, you can also use it in our bubble bar recipe.

How do I know this will make them float?

Seven years of bath bomb manufacturing & I hacked LUSH’s recipe.

Oh, yes I did.

If you look at LUSH’s large floating bath fizzies, they are using Lauryl Betaine and Sodium Laureth Sulfate together in their formula.

Cocamidopropyl betaine and Sodium Lauryl Sulfoacetate are the perfect ingredient hacks because both are natural,  affordable, widely available and make bath bombs float like LUSH!

Floating Bath Bomb embedded with Fizzy Frosting.

Still don’t believe it?  Watch this video.

The video below shows multiple bath bomb designs using our master recipe.

You can use this recipe to make any shape, size, or color. Then, you can embed smaller fizzies in the fizzy to make it spin and shoot out colors. It’s your playground.

Make a Bath Bomb that Floats like LUSH!

Recipe author: FizzButter

Yield: 15 large Wilton hearts. Prep time: 15 minutes


Dry Ingredients (Plus Fragrance)

Wet Ingredients

  1. Before you Begin!

  • Think of this mixture in two parts: DRY INGREDIENTS and WET INGREDIENTS.
  • DO NOT add any wet ingredients to dry ingredients until you are instructed!
  • It is a good idea to wear gloves and a mask when making any bath treats.

  1. Mix Dry Ingredients Plus Fragrance together

  • Put the dry ingredients in a bowl in this order: citric acid, SLSA, baking soda.
  • Add fragrance.
  • Mix together gently.
  • Set these ingredients aside.

  1. Mix Wet Ingredients Together

  • Next, take your Wilton Color and dissolve it in a very small amount of the water (just enough to make it liquid).
  • Once the color is dissolved, add the rest of the water and the Coco Betaine.
  • Stir gently.
  • Set this aside.

  1. Get Ready to mix wet and dry ingredients together

  • IMPORTANT NOTE: Once you add water to the dry mixture the clock is counting and you need to get it mixed and molded quickly.
  • Get another mixing bowl and put approximately 1/3 of your dry mixture in it.
  • Set aside the rest for your dry mixture until the next round of molding.
  • Now, carefully add 1 TBSP of your color/water mixture and start mixing gently. You will see it foam slightly where the water is added. Get that foam/liquid mixed evenly through your dry mix.
  • Do not overmix. Just mix it to where the water is all through the dry mix.
  • Next, make sure you have added enough water. Take a handful of mixture in your fist and squeeze. When you open your hand does the mix stay together or does it fall apart like dry sand?
  • Test the consistency. Does it hold it’s shape without being sticky to your hand. Yes? You are ready to mold.
  • No? Mix in a LITTLE more water. Do the squeeze test.

  1. Mold your floating Bath Bombs

  • As long as your wet to dry ratio is right, molding should be easy.
  • Quickly mold your bomb by pressing your mixture into your mold. Unmold after a second or two (you shouldn’t have to leave these in for them to stay together.)
  • Place unmolded bath bombs on 18 x 26 sheet pans lined with wax paper.
  • You may get sticking in the corner of your mold after a few uses. This is normal and it doesn’t mean you are doing anything wrong. For example, in a heart shape, the point at the bottom of a heart my try to stick after you have used the mold a few times. For that reason, it is good to have a few more clean, dry molds handy for backup.

  1. Cure your floating bath bombs

  • Bath bombs cure best from 60-80 degrees. In fact, the cooler, the faster and better they cure. Do not put them in a high humidity area as it could cause pimpling on the surface of the fizzy.
  • Never cure your bath bombs in direct sunlight, high temperatures or high humidity.
  • Package your bath bombs after they have cured for 48 hours. Even if they look dry on the outside, there is probably still moisture in the middle, especially on larger fizzies. Ultimately, if you package them too early it may degrade the fragrance or make it smell funky. It can also effect the composition of the fizzy by making it slightly soft. Don’t do it.

Get Lavender Essential Oil at Amazon

Troubleshooting your Floating Bath Bomb

Have I added too much water?

You can tell if you added too much water because it will really stick to your hand and you will see your mixture visibly rising out of shape. i.e., you put it in the mold and it sticks so bad, you can’t get it out and it puffs out of shape.

If this has happened, work a little dry mix through it and see if it settles down.

Your target wet to dry ratio is just enough water to make it all stick together and no more.

One final note, if you start to cure your fizzies and they lose their shape and flatten on the bottom, you have added too much water. Large round shapes are the hardest to perfect and any flat design will be easier for a beginner.

Have I used enough water?

If the mix is sandy and doesn’t hold together enough to mold, it is likely you need to add a little bit of water. Be careful to just add a little at a time.

Have I under mixed my wet/dry mix?

You can tell if you under mixed if you get warts on your bath bombs as they sit and cure. It usually shows up very fast. You usually cannot redo them at this point, so just let them cure and use them anyway.

Pro Tip

2 cups of baking soda = 1 pound.
2 cups of citric acid = 1 pound.
Keep this in mind when you need to reorder raw materials.

More information on molds

You can use any kind of metal or milky way plastic mold with this recipe. However, it doesn’t work as well with a silicone mold.

Buy Heart Molds at Amazon

We used a Wilton Heart mold on the yellow hearts and a Milky Way Chrysanthemum mold on the aqua colored flowers with gold shimmer.

TIP:  Mix mica or shimmer with rubbing alcohol and you can paint or stencil your bath bombs!  Or, just dust with shimmer for an adorable touch!

See the amazing selection of shimmer colors at Amazon

Just keep in mind, the less intricate the detail and the fewer sharp corners the better final results.  Also, a flat bottom design like this is easier than a large round one for a beginner.

Floating Bath Bomb made with Milky Way Chrysanthemum mold and dusted with gold shimmer.

Pro Tip

Because of the bubbles, this bath bomb will not be moisturizing like our Butter Bath Bomb Recipe.

Got bath bomb making questions?

Use the blue comment button below and I will answer all questions.

Make a Bath Bomb float like LUSH
Average rating:
5 reviews
by Clarice on Make a Bath Bomb float like LUSH

The bubbles are amazing. I had trubble getting them out of tho mould, did I put too much or to little water?

by Tisha on Make a Bath Bomb float like LUSH

My daughter and I had the best time making these for her slumber party gift bags! Thank you so much!

by Macy on Make a Bath Bomb float like LUSH

I made these last night with the heart cutout and they turned out great. Please post the frosting recipe soon!

by Shirley on Make a Bath Bomb float like LUSH

Thank you! Thank you! Thank you!  I have tried to figure out this for a long time!

by Nancy on Make a Bath Bomb float like LUSH

Yes! Yes! These were great. The only tricky part is the water. You start to get the feel for the mixture. It's fun to make, too.

View Comments

    • Yes, as long as you use the smaller grain citric acid like Milliard here and cure in a low humidity area (under 30%), you will get smooth bath bombs.

      On citric acid, many of the imported citric acids have very large grain sizes and/or non-uniform grain sizes. These change the surface of your fizzy.

      On humidity, we would run a de-humidifier when the humidity was over 30%. Humidity can degrade the quality of your bath bombs in many ways. When you cure in a high humidity area, the surface of the fizzy has tiny reactions to the water and it changes the surface of the fizzy. High humidity can also cause mold to show up later (depending upon ingredients).

      Note: If you are having cracking issues, that is something else.

      Here is a a really low-price de-humidifier from Amazon. It costs around $35.

    • I'm so glad you enjoyed making these!

      The bath bomb cracking is usually because the mixture is overworked before it is packed. Example: if you had sticking and had to repack and remix the mixture more than may crack when drying. You can tell when it's overworked because it starts to feel a bit sandy.

      What is happening is the mixture has already started to form bonds. That makes is so there are less spots for it to bond. Does that make sense? It starts to form bonds right away once it gets wet, so there is a time limit on how long you can use it.

      It may also be that there was too much water.

      It could also be, if they were dried too fast in a hot area. (this is less likely due to it only being some of them).

      If you can post a pic to our facebook page here or tag @howtobathbombs on Instagram. I can usually tell when I see a picture. Each one has a slightly different kind of cracking. :)

  • Question: while reading the recipe for bath bomb like LUSH or butter bombs you reference some ingredients as "3T" or 1 T is this teaspoon or TBSP?
    Thank you

    • Hi, the upper case T is TABLESPOON and the lower case is teaspoon. Thanks for asking!

      T = TABLESPOON = TBSP = 15ML
      t = teaspoon = tsp = 5ML

  • Hi do i leave the bathbomb dry in the open air? Or i kept it a seal tight container? My country is high in himudity or the best way i just put it in the freezer?

    • It won't work in the freezer, or in a you know, it won't work in the oven either.

      You can get a little de-humidifier for around $35 from Amazon Then, cure your bath bombs in a small area but remember that running a de-humidifier can raise your room temperature. Therefore, pick a room you can keep cool. Finally, a lower room temperature is most important for the first 12 hours of curing. After 18 hours of curing, temperature becomes irrelevant.

      Also, check the 10-day weather forecast and pick a day with lower humidity. Do not make bath bombs on rainy days unless you have a dehumidifier.

  • I used to make bath bombs with you years ago, I just wanted to say I look back on those times with great joy and hope you are doing well girl! Fizzbutter definitely spoiled me as far as bath bombs go. ;)

  • Thanks so much for this recipe! I'm so excited to start using coco betaine in my bombs. Do you have any tips for working with SLSA specifically? Ever since I added it into my recipe, my bombs are super soft and never fully harden, they just mush when pressed days later.... my recipe was fine before adding in SLSA, but ever since I just can't get the moisture level right. Do you do anything differently moisture-wise in your recipes when you decide to add in SLSA versus when you leave it out?

    • When you add SLSA in a regular bath bomb (like our butter bomb recipe---no coco betaine), it does take a bit more water than a regular bath fizz and the mix acts slightly different.

      I would need to see your recipe ratios to give better advice (how much baking soda, citric acid and SLSA). Also, are you putting any butter or oils in them? Or, any other chemicals? This all gives me a better idea of what is going on.

      • Sure! Here's my basic recipe for just 1 bomb (I'm really into fine-tuning and hate-hate-hate wasting ingredients....)
        100 g baking soda, 50 g citric acid, (1 tsp SLSA optional)
        Then I take 5% of the weight of the dry ingredients and split that number evenly between my fragrance oil, polysorbate 80 and rice bran oil--so the wet ingredients adjust accordingly to the amount of dry ingredients whether I add SLSA or not.
        Then I usually add approximately 12-ish spritz of witch hazel, plus maybe 3 more spritz if it's acting funny haha.
        Since I last posted, I've found that (with my recipe here) anything more than 1 tsp SLSA per bomb never hardened and usually had a bad crack running along the bomb's "equator" and it would split in half with pressure. --the press I'm using may be the cause of this crack, but I'm still not happy with how squishy these guys are turning out.
        I'm super excited to see how the foam compares when supplementing with coco betaine though.... #snailmail

        • Have you tried this recipe without the polysorbate 80? I would use SLSA instead of the polysorbate 80 for your emulsifier.

  • Thank you for the suggestion! I never realized how much more effective SLSA is compared to poly 80... I've never had trouble with it leaving a ring around my tub, but just comparing SLSA and poly 80 in a small mug, the SLSA works perfectly while the poly 80 leaves vibrant, foamy clumps around the rim every time.

    The poly 80 does give the bath bomb a slower fizzle out though. Maybe I'll use them together still for the nice lingering foam they make, or just replace the poly 80 with coco betaine when it gets here.

    • If you want to slow the fizz down, you can adjust the ratio of baking soda to citric acid. Increase the amount of baking soda to get a slower fizz.

      Start with a 10% to 20% increase...and do a little test. I always make notes as I go.

      BTW, it's so much fun to hear about your testing.

  • Hi,
    I just made my first fizzy bath bombs. I love the foam!

    I got problem with getting the bombs from the molds. Do you think I over worked or had too much water?

    I had some trubble understanding the recipe. Do I use one part wet ingredients to 1/3 of the dry ingredients?

    • This applies to this recipe only:

      On getting out of the molds: was it a very intricate design? If so, sometimes that can be an issue.

      On water: If the bombs were rising out of the molds and grow, grow, growing, it is for sure too much water.

      When it is exactly right, it is just enough water to make it all stick together. And, the mixture feels kind of like taffy. Unless, you had major cracks after cure, I do not think it was over-working.

      I find the milky way molds did not stick much (unless I used too much water or they are very intricate). And, I would cut out the mold so I could hold one mold easily in my hand and pack it with the other. I found metal molds to stick a bit more.

      On the recipe, it is 1/3 of the mix to 1 TBSP of liquid. However, due to your climate and mixture, it may be slightly more so use that as a base and increase it, if necessary. Once you find the perfect amount of water.....weigh and record. Then, use that amount every single time. You can do that with the wet AND the dry. You will nail it every time after that.

    • No.

      We experimented with corn starch but it can make your bath bomb softer, shorten it's shelf life, and it usually doesn't add any benefit to the product.

      We used corn starch only in the fizzy frosting recipe because without it the frosting will flatten out right after it is piped.


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