Bath bombs are usually a great choice for both beginner and advanced crafters; after all, the recipe is quite simple. But simplicity is no guarantee for success, it takes practice. Bath bombs are (evidently) sensitive to moisture, therefore they can fall apart, crumble or even fizz incorrectly. Below, we will discuss some reasons as to why your bath bombs keep crumbling and what to do about it.
But basics first: bath bombs are made with 1 part of citric acid and 2 parts of baking soda (causing the fizzing reaction when they get in the water). They usually require witch hazel in order to hold together. After you use those basic ingredients, you can proceed to customize them with fragrances, colors and even glitter.
Your bath bombs could be crumbling because your mixture is too dry, or incorrectly packed in the molds. If you don’t press the mixture well enough when you are molding them, you will be left with crumbly bath bombs once the mixture dries. The mixture should feel like wet sand and hold its shape when you squeeze it.
You can add witch hazel while you mix until you get the correct consistency, as it will add a moisty texture, thus prevent the bath bomb from crumbling. If it cracks after you unmold it, the mixture was likely too wet and had been expanding in the mold. You can use less witch hazel (or use it instead of water).
Humidity can also play a good part as to why they keep crumbling. Among other reasons we have:
The top choice for making perfect (and crumbling resistance) bath bombs are stainless steel molds, bath bomb presses and rigid plastic molds. Silicone molds also work but you have to make sure that you can press the mixture in very tightly. Also, check the quality of the molds.
Not Adjusting Your Recipe
As we said above, humidity plays a good part in ruining a bath bomb, so there’s not ‘one size fits all’ when it comes to bath bomb recipes. You can follow different recipes perfectly without getting the expected results. You have to adjust the wet ingredients.
Add the wet ingredients slowly, and then squeeze the mixture in your hand. If it holds its shape after you open your hand, you made it right. If not, add a bit more of witch hazel or alcohol, but not too much. Repeat until the mixture has the right texture.
Removing Them Before They Are Completely Dry
Bath bombs should be left in the molds for at least 6 hours, and even overnight so they can get completely dry. Removing them before time will cause them to crumble.
Practice makes the master. If you don’t want to waste fragrances, oils and different ingredients because you are still not sure on how to make the bath bombs, you can always practice with the basics (baking soda, citric acid and water) until you get it right.
You can even make different mixtures with different amounts of liquid and let them sit overnight. That way you can not only get an idea of how the mixture should feel, you can also test which recipe will work best for you. Water will fizz the most. Witch hazel has some alcohol so it will fizz a bit less and pure alcohol will fizz a lot less.