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.

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

Coco Betaine Buy Coco Betaine at Amazon

Coco Betaine is very inexpensive and this 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 with Fizzy Frosting

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 authorFizzButter

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

NOTE: INGREDIENT NAMES LINKED TO AMAZON FOR EASY PURCHASE.

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Dry Ingredients (Plus Fragrance)

Wet Ingredients


  1. STEP 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. STEP 2: 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. STEP 3: 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. STEP 4: 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. STEP 5: 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. STEP 6: 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.

Lavender Essential Oil
Get Lavender Essential Oil from Amazon

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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.

Wilton Heart Cut-out
Get fast at Amazon Prime.

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 below (sold out on Amazon).


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!

Click for Amazon Prime Link Gold Shimmer Buy from 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.


chrysanthemum mold
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.  Even if you add oils and butters, they will partially emulsify.

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Make a Bath Bomb float like LUSH
Average rating:  
 6 reviews
by Jane on Make a Bath Bomb float like LUSH

Hey, this recipe sounds amazing, but any chance you could tell me the UK equivalent to these measurements?

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?

Clarice it sounds like it may have been too much water.

Did the batch expand and expand and rise out of the mold? If yes, it was too much water.

Also, what kind of mold did you use? I would stay away from silicone molds because they really stick with this mixture.

I like the Milky Way and metal molds better. Cut each Milky Way out of the big square piece and use it in your hand one at a time. They work GREAT! And, there are so many styles.

Here's the kind I'm talking about:
https://amzn.to/34ymD5h

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.


Got bath bomb making questions?

Use the comment section below and I will answer all questions.


65 Replies to “Make a Bath Bomb float like LUSH”

    1. 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.

    1. 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 once….it 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 https://facebook.com/FizzButter/ or tag @howtobathbombs on Instagram. I can usually tell when I see a picture. Each one has a slightly different kind of cracking. 🙂

  1. 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

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

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

  2. 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?

    1. It won’t work in the freezer, or in a container…so you know, it won’t work in the oven either.

      You can get a little de-humidifier for around $35 from Amazon https://amzn.to/2YUSR77. 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.

  3. 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. 😉

  4. 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?

    1. 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.

      1. 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

  5. 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.

    1. 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.

        1. I believe witch hazel merely adds cost to your product, without adding any real benefit. But, you can likely replace the water 1:1 with witch hazel. I would not use alcohol, though.

      1. Oh no! I missed your reply and never realized till just now 🙁
        I’ve just recently gotten back into SLSA, thank you again for all the helpful suggestions! Every day that goes by waiting for the bombs to properly dry and have better luck floating is agony…But I look forward to tweaking the citric acid percentage next, especially with my pyramid molds that tend to dissolve VERY quickly with all the surface area.
        Do you have any favorite fragrance (or essential oil) manufacturers you would suggest?
        Hope you’re well!

        1. I bought from about 7 different suppliers. It’s best to try one who has reviews so you don’t end up buying a bunch of fragrances you don’t like. If I had to only pick one, I would go with Wholesale Supplies Plus due to the variety and quality.

  6. 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?

    1. 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. It feels unusually cold, too. Be sure you use cold water because it will stick less.

      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.

    1. 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.

  7. Hi there! I need to make my bath bomb spin and I see in your frosting recipe you mention we can use left over frosting as an embed to achieve just that. Thing is, I won’t be carrying the frosting product. So what do you suggest I do? Also, does the embed need to be placed in a particular way? And I really wanna thank you sincerely for all of the valuable content you are sharing with us, you’re truly a Godsend.

    1. You have to create ‘imbalance’ somehow in the bomb. One way you could do it add some kind of air pocket to one side (hence, the fizzy frosting on this cupcake http://howtobathbombs.com/wp/2019/02/13/fizzy-frosting-recipe-bath-treat-topping/.
      Or, another way would be to make your batch fizz at different speeds. If you are using two colors…on one color use more citric acid and decrease that same amount of baking soda (this will make it fizz faster).

      Next, if you try to use the two colors in a way that will make your form ‘unbalanced’ you have a better chance for spin (think about how your shape will float in the water and make the colors work against each other). Example, let’s say you had a flat airplane shape…you could make one wing red and one blue…each one would fizz at a different speed because you have different citric acid ratios in each mixture!

      Some shapes are harder to make spin. You have to experiment a bit and think about shape when you design this fizzy.

  8. Good afternoon,
    I love this website, it has helped me out a lot! I have an incredibly large project underway and would truly benefit from your insight. I’ve seen you say you are willing to help people with their recipies and I was hoping I could contact you more directly to discuss mine more thoroughly.
    Thank you for the site again and I look forward to hearing from you.

    1. I don’t find it necessary to weigh ingredients with the butter bomb recipe because it is very forgiving! However, weight would make the measurements more precise. Maybe, you could use weight measurements if you have problems with the recipe.

  9. I love making these so much, however my bombs keep cracking. ive tried packing the molds (metal) and not packing them and its still happening. they dont look cracked when i first set them down but theyre cracking during the drying process. any suggestions?
    thanks so much!

    1. It sounds like it may be one of two things: overworking the mix or too much water.

      First, too much water is pretty easy to spot..is will also cause flattening on the bottom, or over-rising.

      If that is not happening, it’s most likely overworking. But, how does it get over-worked?

      The most common way the mix gets over-worked is if you have to re-mold due to sticking. So, if you have to re-mold your bath fizzies, each time you increase the chance for cracking. This does cause the kind of cracking you are talking about…it cracks after it dries. You can also mix it too long but that is not as likely.

      There are a couple other random times I’ve seen cracking (less common):
      1) I cured in a very warm room in direct sunlight (it caused a 90% cracked disaster).
      2) Once, I saw shea butter from a bad supplier cause cracking our butter bombs.

      Oh, and packing tighter is generally better than packing loose.

      I hope that helps.

  10. Hi! I’m looking forward to trying this recipe out but can only find SLES (in liquid form) at a reasonable price (SLSa powder is outrageously priced here).

    I know I can sub in the SLES and combine with the baking soda the day before I make the bath bombs, but I’m not sure on quantity. 1 cup of liquid SLES seems like it would be WAY too much moisture. Any ideas?

    1. Ellie, I don’t recommend doing that unless you have a lot of experience with the ingredients because you may end up wasting your money on rejected bath bombs.

      Also, I believe your fizzy will be less bubbly. If you only use a liquid bubbling agent, you won’t be able to use as much as you would if it were dry (because it will ruin the whole batch just like if you use too much water).

      If you are mixing in the day before to get it to dry out…that could be interesting. It’s fun to experiment so just write down what you do and record the results. I always take pictures, too.

  11. Hi!

    Firstly, thank you so much for this, I’ve been making bath bombs for YEARS but had to stop when I was unable to produce these floating colorful foaming bombs!

    A few questions, One is about the wilton colorant, I’ve used this before, and it has stained skin. Any ideas on that? I never used them again because I was terrified that it would stain my client’s skin.

    Two, I made this recipe, and while it did sit on stop and foam, it only did that for less than ten seconds and then sank to the bottom and refused to come back up. It was still activating under the water, but just not floating anymore. I’m so close, but I’m having these troubles. I really hope you can help, and thank you SO much again, this has been my DREAM for years. I’m so happy to have help.

    1. I found the wilton only has a few colors that stain (rose pink), and most of them are fine. The thing I find most frustrating about Wilton is that they fade in sunlight (in most products, but not all).

      ON the floating, it sounds like you are not using enough of the Cocamidopropyl betaine. When you use it, no matter how small the piece of bath bomb material, it will float. But don’t add too much, because the mixture will rise and rise out of shape and be ugly (but, it will still float)!

      The fact is, when you use Cocamidopropyl betaine with SLSA, it injects so much oxygen into the mixture….it has no choice but to float!!! You can’t sink the bath bomb. No matter what, do not leave out this ingredient or this recipe will not work.

  12. Hi! Thank you for such fabulous recipes. My question is re dyes. I know they have to be water soluble but would love a brand recommendation for colours that remain bright and dont fade. Thanks so much!

    1. This is the toughest thing in all of bath bomb making. We used Wilton but they do fade in sunlight (almost instantly). There are mica’s but they have their own issues. Some of them react with the citric acid and add a disgusting odor. I cannot help with this particular issue. I stuck with Wilton because, for production, it was the easiest colorant to use. In home crafting, I would experiment with pigments.

  13. Good morning!
    I am wondering if using mica as your colourant (provided it performs well), is there any way around having to use Poly 80? Or any time mica is used for bath bombs Poly 80 is required?
    Thanks so much, Kate.

  14. Does this recipe work well with stainless steel sphere moulds? I’ve been making basic bath bombs for years but every time I’ve tried to used them my bombs have got stuck.

    1. As long as they are a bit flexible so you can squeeze them. There just aren’t as many cool shapes for these if you go steel. I like the milky way soap molds best for this recipe. I like the steel best for the butter bath bomb.

  15. Hello,

    I’m new to bath bomb making, and one thing I noticed (and something I shouldn’t expecpt, but would love it if I can acheive it) is that my bath bombs do not smell nearly as strong as Lush’s or store bought brands. The smell is super strong when making, but when using them in the bath, the smell fades quickly and really doesn’t get on my skin. Is it the chemicals they use or artificial fragrance, or both?

    1. Artificial fragrances last longer than most essential oils. I found that especially citrus essential oils like grapefruit just lose their fragrance immediately. It doesn’t even matter how much you use. Go with the most concentrated formulas, do not skimp on quality, and you have to test the fragrances. Usually, the stronger it is in the bottle, the stronger on the product.

      I always did a paper test, too. So, take card stock and cut into square, put a dropper of fragrance on it. Check it after one day and then up to five days. If you smell nothing, it’s going to smell like nothing in the bath bomb. Also, most fragrances smell different after they dry (vs in the bottle) so this test is a must.

  16. Hi Kcat,
    first & foremost thank you for your detailed contents.
    i have done several research and i came across some recipe with these 2 ingredients (CORNSTARCH & EPSOM SALT).
    do you by any chance have any experience with these 2 ingredients.
    how are they different from yours?

    1. I love Epsom Salt for the butter bath bomb recipe but didn’t use it in this product. The reason is that you really can’t get enough of it in the floating bath bomb to make it beneficial. Also, it will take away from the ingredients that react together. You could use it if you want to slow down the fizz (for example). Bottom line, I love it in the Butter Bomb and made millions of them with it but I didn’t use it in the floating bath bomb.

      I did use corn starch in some products,

  17. when you say cup, please advise how many grams this is. im wanting to use Cocamidopropyl betaine with 600g bicarb. please advise how much i use. maybe add a cup to gram and teaspoon to milliliter conversion on your site as google offers different grams for US cups depending on the ingredient. thanks

  18. Hi!

    I’m wondering what your thoughts are about replacing SLSA with SCI (sodium cocoyl isthionate)?

    SLSA is incredibly difficult in our country.

    Thanks in advance!

  19. Hi there! I am about to make this recipe but I didn’t see a “binding” ingredient such as corn starch or cream of tartar. If I’m planning to ship these will they be hard enough and not break in transit if I use this recipe?

    Thank you!

    1. The ‘binding’ happens when you add water to citric acid and baking soda. The chemical reaction causes the ingredients to bind. I tested corn starch in the Butter Bath Bomb recipe and didn’t find it to be beneficial to the product. However, if I lived in a moist climate I would have considered it for it’s moisture absorption properties. I also think they can add a slight ‘film’ to the water when the bath bomb fizzes.

  20. Please understand that I am not good at English.
    First of all, I found the post very useful. Thank you.

    Sir, I have a question.
    My recipe is almost the same as the recipe on the post.
    But I put a bath bomb in the water, it breaks with a ‘puck’ sound.
    What’s the cause?

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