Bath bomb color help

[Autumnleigh93]

Hello,

I currently make bath bombs using mica to color them and they turn out rock hard and perfect pretty much every time. I have been experimenting using different coloring agents to try to get a richer color in the bath without leaving residue on the tub.
I use the same recipe but instead of the mica I have subsituted with a few drops of liquid color (ingredients: glycerin and red 30) for example. Every time I use the liquid color by bath bombs seem hard for the first day or two but about 3-5 days in they stay turning soft and expanding.
Here is the basic recipe Im using :

Baking soda 1cup
Citric acid 1/2 cup
Epsom salt 1/4 cup
Coconut oil 1 tbsp
Fregrance 3-9ml
Color 1 scoop of mica or 3-6 drops of liquid.
A few Spritz of witch hazel


i am open to any and all suggestions at this point. I have used bramble Betty's la bomb colors, rustic essentials gel colors and a gel toner from a local lady all with the same results.

 

[snappyllama]

Glycerin is probably drawing moisture out of the air. Are you in a very humid area or has it been raining lately where you are? Once they get their initial hardening, maybe try wrapping them?

 

[Autumnleigh93]

I'm in Sacramento. It has been rainy but does that mean I'm out of luck? I have tried wrapping them and they still end up getting soft inside the shrink wrap after a few days and expanding as much as they can And if they seem fine I try to unwrap them and they just crumble. Is there a different type of color I could use that would color the water without leaving a residue?

 

[shunt2011]

I agree that it's the glycerin causing your issues. I use either mica or the bath bomb colorant from WSP or Nature's Garden. I don't make a whole lot of them but it has worked for me. I also don't make them really bright or super saturated in color.

 

[Navaria]

I started adding a bit of polysorbate 80 in mine and they quit leaving a colored ring in my tub. Granted, I don't use an extremely heavy color to begin with but even what I did would leave a ring. The PS80 helps to emulsify the oils I add with the water. The oils were what was causing my ring.

 

[shunt2011]

I too use PS 80 in my bath bombs.