Discoloring fragrance and bath bombs

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ImpKit

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A simple question: do discoloring fragrances (particularly those with high vanillin content) cause bath bombs to discolor over time as well? Do they change the color of the bath water if you color the bombs?
 
Vanilla will discolor most things that are not anhydrous. WSP sells a vanilla color stabilizer that can be used in bath bombs, it is actually the one they sell for CP soap. According to the staff members who answer questions on the site, even bath bombs made without water will discolor with vanilla in them and no one seems to know why.

https://www.wholesalesuppliesplus.com/products/vanilla-color-stabilizer-cp-soap.aspx
As far as coloring, I have no idea. I don't actually make bath bombs. I only know about the VCS at WSP working for bath bombs because I came across the info about it in the Q&A section.

I would suggest you make testers and see for yourself what happens color-wise when you use different ingredients, because what works for someone else might not work in your recipe anyway.
 
Vanilla will discolor most things that are not anhydrous.
...sometimes. I have a few high vanillan fragrances that in soap will turn brown (or in one case dark green) but in B&B products it doesn't discolor at all. I haven't made bath bombs, but so far my experience for sugar scrubs and lotions has been that I don't need to use a stabilizer.

I would do a small test batch and watch them over the course of a few weeks. I don't know how much the end product affects the discoloration, but I was surprised by my experience with scrubs and lotions.
 
...sometimes. I have a few high vanillan fragrances that in soap will turn brown (or in one case dark green) but in B&B products it doesn't discolor at all. I haven't made bath bombs, but so far my experience for sugar scrubs and lotions has been that I don't need to use a stabilizer.

I would do a small test batch and watch them over the course of a few weeks. I don't know how much the end product affects the discoloration, but I was surprised by my experience with scrubs and lotions.
Correct, because sugar scrubs are almost always anhydrous. If you add water, or ingredients that contain water, it tends to dissolve the sugar a little bit over time. The grains will be smaller and not as scrubby. So usually the recipes that I see don't have water at all, and if they do it's a tiny amount to limit the sugar being dissolved.

My usual lotions are anhydrous (lotion sticks) so vanilla doesn't discolor them. A regular lotion that is mostly water would probably take longer to discolor than the shelf life of the product. A lotion is going to have way less fragrance in it percentage-wise than soap, (which is also not anhydrous, hence the discoloration) and since lotion is in contact with air less than soap (in a bottle instead of exposed to air), it makes sense that it takes longer to discolor than soap does.

Bath bombs are the oddball anhydrous product that can discolor with vanilla.

I totally second the advice to make test batches. Keep them in the bathroom (where most people store them before use) and keep detailed notes.
 
Ooh, I haven't checked my bath-bombs with vanilla in a while, but they have discolored!
Vanilla Oak had a little brown mica to start with, but has definitely evened to a darker brown, which is very fitting. Black Amber and Lavender started purple, but now has dark splotches, which also fits the name well. I'll have to see if that transfers to the bath or to me later, but given the tiny amount of FO I use versus the amount of water in the bath tub, I would be very surprised if it has any impact on its performance whatsoever. FWIW, my recipe has Cocoa butter, Polysorbate 80, and FO as the only things sticking it together. And, as you might guess from the plastic underneath them, I usually keep my bath bombs wrapped so they don't absorb as much moisture from the air.
 

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