This Is Why Your DIY Bath Bombs Are Cracking.

If you are new at making bath bombs, you probably will encounter at some point one of the most common problems all bath bombs struggle with, cracked bath bombs!

Your bath bombs crack because, most likely, your mixture is too dry. It must feel like wet sand and hold its shape. Another reason for your bath bombs to crack is a wet mold; if it’s too wet, your mixture will start expanding and therefore cracking.

Discover the ‘secrets’ Professional Bath Bomb Makers use to create luscious bath bombs with this step-by-step guide. You’ll have a priceless reference collection of product recipes with natural ingredients designed to create a relaxing spa atmosphere in your own home.

Why do DIY bath bombs crack?

Cracked bath bombs or fizzies are very common, and it is mostly something you can ignore if it’s for personal use. But if you are planning on selling and making bath bombs, you need to make sure these cracks are not visible, and by doing that, we need first to understand why this happens. 

Cracking or crumbly bath bomb mostly occur due to the mixture being too dry. This mostly happens at the stage when you leave your bath bombs to dry. Bath bombs cracking when drying could be avoided by adding more oils to it making it moister and giving it texture, which leads to less cracking and crumbly bath bombs. But to tell you the truth, there can be many reasons for your bath bombs to crack or crumble.

Here is a shortlist of probable causes.

  • Not using the right formulation.
  • Did not store them correctly.
  • Humidity levels are off.
  • The living area is too humid. Bath bombs are very sensitive to moisture.
  • You did not use the proper mixture. This is also a widespread mistake most people make when they start making their bath bombs. 
  • Too much liquid. Or the liquid was not enough.
  • The ratio of additives, such as salt or clay, was off.
  • Packing the mixture into stainless steel molds might also be the reason.

As you can see, many things can lead to your bath bombs cracking, and it is sometimes hard to find out what the problem is. So, I would recommend cross-checking if you have any of these problems. 

Let’s take fizzies; for example, if they are too wet and you put them in the mold, the mixture will expand, and once you take them out, it will crack. 

In the end, we should understand that there can be so many things that lead to cracks; even the smallest difference in weather, the room temperature, or a slight gram (2 or something) off might lead to a different outcome of bath bombs. 

How to fix cracked bath bombs?

If you are planning on selling your bath bombs but have cracks on them, you need to fix them before sending it out. You might think this to be a difficult task, but surprisingly, it’s straightforward!  

You will need dry ingredients:

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Baking soda

Epson salt (optional)

Cornstarch (can use the one in your kitchen)

Nutiva Organic Cold-Pressed Unrefined Hemp Oil, 24 Ounce

Wet ingredients:

Oil (same as you mixed previously) Hemp oil is a good choice as it is good for the skin.

Food coloring in case you have used in the batch you wish to fix so the fix cannot be seen. (unless you have used different colors, then it’s okay; you can just skip this part)

You start mixing as you would typically do with making a bath bomb, but make sure you have the right consistency. So this means making sure it feels like wet sand and holds its shape when you squeeze it. Then you take a little of it and rub over the cracked spots.

It should fill them up, and the final result should look like the cracks rarely happened. If there are small parts that crumble away, you can also fill them with the same.

Below there is a video really well explains how to fix it. I think it speaks for itself.

What can you do to avoid cracking bath bombs?

If you can avoid having cracks, you don’t have to bother fixing them anymore, simple as that. As mentioned previously, your mixture was probably too dry, and thus it has cracked. An excellent way to know if it’s not too dry (or too wet) is to feel the mixture with your fingers.

The mixture should feel like wet sand and should hold its shape when squeezed. Use one hand to add Witch Hazel and the other to mix until you reach the consistency of wet sand.

Once your mixture is ready, you need to mold it. Molding is probably the second most crucial part of bath bomb-making, and if you don’t do this part right, you might end up with cracked bath bombs and or uneven ones. You can use many types of molds like stainless steel molds or plastic molds. But it’s crucial to remember, your mold cannot be wet, or else your mixture will start expanding and therefore crack.

But in this example, we will focus on the scoop technique.

First, make sure you use a bath bomb scoop to scoop the mixture. It will make your life so much easier, and to be honest. You probably won’t go back once you have it. A good tip before starting is to put the scoop in the freezer. Bath bombs sometimes release easier when the scoop is cold.

So, scoop up with the bath bomb scoop and squeeze hard and tight. Make sure to clean the edges of the mold with your finger so it looks nice and clean. You can also tap on the mold using another spoon (or any metal, for that matter). This will help loosen up the bath bomb within the mold.

Afterward, release the bath bomb in the palm of your hand and put it aside to let it dry. And that’s it, nothing more to it.

Adding oil.

You can also add oil. If the relative humidity is the cause of the crack, this should do the trick. Try to make bath bombs only on dry days, when it’s not too humid or raining.
If it’s crumbling, then it means you added too much oil. The same story, of course, makes sure to dry them on dry days.

Use a scale.

Use a scale to weigh everything you put in. I know this sounds stupid and obvious to most of you, but many people tend to think that making bath bombs is almost similar to cooking, where you can go with the feeling. Well, as discussed earlier, that is not the case.

You cannot add more or a little less of any ingredient, as it may cause cracks afterward. The worst part of working like this is, you won’t even know what caused the cracks.

Follow the instructions.

Follow the instructions as well as possible. So this means that you don’t go and add something extra to it or skip a part, so follow everything to the T! If you feel comfortable adding something extra to it or to test things, do it once you have everything mastered.


People who just started making bath bombs probably struggle the most with cracks. While veterans know how to avoid it in most cases, they also fall victim to it from time to time. The fact is that so many factors can cause this that it is nearly impossible to avoid it altogether.

The main thing to remember is that cracked bath bombs are not a failed batch; you can fix it and make it look like it never cracked. One should always try to avoid having cracks instead of trying to fix them. And this can be achieved by having an environment where the humidity can be controlled.

If you want to invest in something, this would be the best investment you’d make. The moisture in the air can cause cracks, and that’s something that’s easily controlled. Having too much liquid or too little can be fixed very easily.

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