I am in possession of ten fragrance oils that I've been buying here and there. I noticed that some of them discoloured the batter badly but never managed to take notes properly so that I could know exactly which ones do it. Yesterday I decided to test most of them and so I did. Results: the worst is ambergris (if I found the correct translation for Slovenian "ambra"). Lavender, patchouli and sandalwood fragrance oils show medium discolouration. Antique rose and geranium produce only slight discolouration. I can't say for lemongrass FO. I have an additional FO of orange colour and with no label whatsoever. It produced darker orange. I expect discolorations to develop further and will try to follow up.