Bath Bomb Failures: Bath Bomb Crumbles, Bumps, Not Holding Shape

Bath bomb issues and failures

Why Is my Bath Bomb Failing?

First and foremost, let's start with this. 99% of the time when you have bath bomb failures due to not holding it's shape, it has to do with moisture issues. So the first thing we are going to discuss is about climate and how this may effect your bath bomb.

After that we'll discuss some common issues most people run into when making bath bombs, whether you are a seasoned pro or a complete newbie.

Can Climate Effect My Bath Bomb?

how climate effects bath bombs

Yes, Climate can in fact effect your bath bomb. If you live in a more humid environment and plan on making bath bombs for selling purposes, it may be wise to invest in a dehumidifier. Usually if your mixture is on point, and you're keeping below about 40% - 45% humidity when storing your bombs, they will hold up just fine.

You may even find above that percentage they do well. However, we have found the ideal humidity is under 40%. It may also help once you wrap your bath bombs.

For instance, after they've dried for 24-72 hours, wrapping them in shrink wrap will help keep there consistency. Another solution in humid climates is to watch what binder your are using. It may be beneficial for you to use a binder like alcohol because your ingredients will dry much faster then using a spray bottle with water.

For those of you who live in a dryer environment, instead of your bath bombs being on the wetter side and crumbling or not holding shape due to moisture in the air, you may find your bombs are cracking because they are simply to dry.

A few solutions to your problems would be using more water as a binder or adding a touch of oil to your recipe, as these both will help with keeping your bath bomb a little more moist. You could also try shrink wrapping your bath bombs a little sooner then usual, however your have to be careful not to trap to much moisture because this could lead to other problems.

Storing a Bath Bomb

how to store your bath bomb

One of the most important steps to bath bomb making is properly storing them so they can get the drying time they need. Now one of the important things to remember here is that depending on the ingredients that you use, like hardeners and what binder used (i.e. water vs alcohol) will also have an impact on this process. I tend to find if you use water as a binder the drying process is longer. If you use a heavier amount of carrier oils this also impacts drying time, increasing it.

Hardeners help to draw moisture out as well so using these may help dry your bomb faster, however keep in mind it may also have an effect on the density of your bath bomb, to put simply, using a lot of kaolin clay or cream of tartar equals a greater chance of the bath bomb sinking, so you have to weigh that into your equation of what you really want from you bath bomb.
Typically we let our bath bombs dry with humidity less then 40-45% roughly 24-36 hours before shrink wrapping them for packaging. After even shrink wrapping we will store in an airtight container (like plastic storage bins) that way they don't end up absorbing to much moisture in the air.

The shrink wrap helps, but why take the chance, remember bath bombs may not be the hardest thing to make, but they tend to be very finicky if you're not precise with your process.

Crumbling or Cracking Bath Bomb!


why is my bath bomb cracking

So there can a varying reasons of why you bath bomb may crack, but it again usually has to do with your wet/dry ratio. So if your bath bomb is to dry or your mixture is to dry it can crack while drying or even when you go to un-mold. Sometimes you can't tell until it starts to dry and then you may see small cracks or imperfections in the body of the bath bomb.

  • To correct this, try purchasing a digital thermometer with humidity gauge, that way you can make sure it's not to dry in the air for where you are storing your bath bomb.
  • Try using water as your binder.
  • Try adding some light carrier oils to the mixture as this will help it to stay moist.
  • Make sure to pack you moisture tight. "Under Packing" (if you will) can also cause your bath bomb to crack. You can also purchase a bath bomb press machine which will give you the perfect amount of pressure every time!


why is my bath bomb crumbling

Again this failure is usually do to your mixture being to dry or packing issues.

  • Make sure your are packing your mixture tight. You don't have to go crazy, but try packing it slightly with your fingers as you add more mixture to your mold.
  • Like we mentioned above, try water as your binder. You can also use witch hazel, but we either use water or a water/alcohol mixture 50/50.
  • This may also be a time to try a hardener in your mixture. Remember this effects the density of the bath bomb, so be aware of this. A little hardener goes along way. We've found even adding just 1 teaspoon can have a huge effect on the hardness of a bah bomb. Clay may help, but you still have to pay attention to your wet ingredients, because with hardeners, they tend to draw out moisture even faster, so you may have to include extra oils, or moisture from somewhere.
  • You may also try and premix your colorants, like blooming dyes or adding a wet ingredients to dissolve your powders prior to adding to your mixture as this will add some additional moisture.

Bath Bomb has Developed Bumps!

This is another common problem that bath bombers have with their mixture at one time or another. The important thing here is to always make sure you are keeping track of batches and which ones worked well and which ones didn't.

Usually bumps have to do with the mixture being to wet. So if this happens, lessen your binder amount or lessen the amount of oils you are using in your mixture. I've also seen this occur if your humidity is to high where the bath bombs are being stored, so they start to soak up that excess moisture in the air.

Where to Place Bath Bombs After Molding and Un-Molding?

where to place my bath bomb when unmolding

So another common issue that happens in your quest to making the perfect bath bomb, is once un-moling it, simply where do I place it so it doesn't develop a soft or flat bottom, making it less spherical. This is usually an easy fix. Even if your mixture is a little wet, but still holding it's shape, place it on a soft cloth or the best option for us is a piece of egg foam, like picture above.

You can purchase these on Amazon for very cheap, and it's perfect for round bath bombs! This will 99% of the time fix the issue. Now keep in mind if you un-mold your bath bomb and place it on a soft area to dry and it immediately crumbles or falls apart there is an definite issue with your mixture and it may be way to dry or way to wet.

Believe it or not, this is a science and depending on where you live it can totally effect the bath bombs themselves. The most important tip is practicing with different recipes & ingredients, no one gets it 100% on the first try. Heck we still experiment all the time to find out what works best and depending on our intentions of each bath bomb.

So don't get discouraged. The great thing is, you can make really small batches with minimal ingredients to figure our a base of what works best for you and then scale it up. As bath bombs continue to increase in popularity, you should for sure enter into the scene, but be patient.

If you come across other issues, be sure to leave a comment and we will answer your questions as soon as we can. Please remember that many people have the same issues with making bath bombs, so feel free to comment on each others posts and questions as well, as we can all help one another out!

Thanks for stopping by, and be sure to share our posts on social media if it's something you find helpful. See you next time!

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