Have you ever molded the perfect bath bomb only to try and move it after drying to have it crumble through your fingertips? Grrrrrrrrrrr. This can be extremely frustrating!
Powdery bath bombs typically mean that you don’t have enough wet/binding ingredients in your formula. It can be especially common if you live in a dry climate with little to no humidity.
If you add clay, oatmeal or other ingredients that absorb moisture, you might need to use more binder or wetting ingredients than usual as the clay, oatmeal, etc., can absorb moisture.
You can try a few things.
Use More Wetting Spray
Whether you use alcohol, witch hazel or water to wet your mixture, spray your bath bomb mixture a bit more than you typically do. You might be wetting it just enough to mold and hold together temporarily, but not enough to bind it all together permanently.
One tip for testing your mixture before molding is to grab some mixture and press it together in your hand tightly. Hold your hand about 12″ above your mixing bowl. Drop your hand-pressed bomb. Does it hold together or break apart? This might help you determine if you need more wetting spray.
Use Water to Bind
If you are currently using alcohol or witch hazel to spray and bind your bombs, switch to water. Water usually creates a harder bath bomb that doesn’t crumble. Alcohol evaporates so quickly, without activating enough of the mixture. Water actually activates a tiny bit of the mixture, hardening it up quickly. You can switch to using water only, or you can use a combo of alcohol + water or witch hazel + water.
Obviously, if you use too much, you’ll get warts or too much activation in your bombs.
Include Oil in Your Formula
Do you include an oil in your mixture? If not, try adding some avocado, grapeseed or other light oil. Oil can help to bind and harden your bath bombs. The oil in combination with your wetting spray can help to create a hard bomb.
Too much oil can cause a bomb that doesn’t dry. I typically add 1-2 teaspoons (5-10 grams) per cup (or 250 grams) of baking soda.
Cocoa Butter
Butters can help to harden your bath bombs by solidifying quickly after molding. It literally acts as a glue, holding your ingredients together. Pick a brittle oil such as cocoa butter or kokum butter for best results. Melt it before adding to your bombs and quickly mix it in.
There isn’t a perfect solution to powdery bath bombs, but if you try a couple of the suggestions above, you’ll be able to fix your powdery bath bomb issue. The first thing to try is to switch to using water to bind your bombs. That will usually fix the issue easily.
Have you had powdery bath bombs in the past? How did you fix the problem? Please leave a comment!
Thank you so much! This information truly was needed lol
Take care and stay safe Leanne
Hi, in our building the humidity is around 25 during the day drops down to 15-20 during night. i believe that is what causing some of our bath bombs to crack over night. what is good humidity level to dry bathbombs? thank you awaiting your reply
40% is the best humidity level for molding them and drying them with out cracking
Hello, my humidity goes up at night so I’m concerned about how to dry my bombs that I’ve made during the day. Would placing them in A covered container help? The ones I made yesterday were powdery this morning.
Hi Amer! It’ is possible that the humidity is dropping too low and causing your bath bombs to crack! You can try using a humidifier and it might also help to reduce your hardeners a bit. Ingredients like cornstarch, kaolin clay and cream of Tartar might be contributing to them cracking in low humidity!
Hi,I use polysorbate 80 and an oil and that usually binds my bath bomb but while it’s drying it gets these wet lumps on the top after a while. Could that be because of the moisture the tapioca starch is attracting? If so how do I rectify this?