The stickblender:
You have a way to check. Does it have a metal or plastic bell? Also - if you look at the blade, is it matted? Or rusted? Turned black`ish? If it is ANY of the above (rusted, black etc then stop using it right away and get a new one)
However, if it is shiny and not rusted, and looks clean, then it sounds like it is stainless steel blade. That should not be an issue. My food stickblender has an aluminum bell, but stainless steel blade, so that would not have been suitable for soap.
The coconut increases the smell... Have you used the same coconut oil throughout, but switched the other oils? And you use distilled water? Tap water/well water can have metal ions in them that can foster rancidity, even if it doesn`t make it apparrent straight away.
The palm oil, how old is it? Is it a no-stir? How does it smell when you put your nose up to it?
You said
i don't pay particular attention to where I cure my soaps:
Well, actually it would be wise to do so. A stable environment is key to let the soaps cure. Fluctuating temps can affect the soaps.
Are they exposed to sunlight/light from windows etc, when you let them cure? Thinking that the warmth of the dryer room/sun will cure them faster, evaporating water quicker etc. ?
Have you tried to use an chelator and ROE before? I am getting out of options now, mentioning everything I can think of under the sun (others may have some better ideas)
If all else fails - if it were me I would try the following:
Make a brand new batch if you can (just a pound).
- All oils must be fresh, straight from the store,
no oils from previous stash, but all new oils.
You don`t have to get a lot, just to make a small batch!
-Keep it simple: olive, coconut and castor (and another one if you wish, but we just need to try a new recipe to see if there is anything that will change to the better).
- NO fragrance.
-Use distilled water, new, unopened.
-I would switch the stickblender.
If there is someone you can borrow one from that are willing to lend it to you for soap, then I would use that, if it has a stainless teel knife.
-Clean the mold well.
- Make the soap.
- After it has hardened, cut it.
- Let it cure on an airy surface, no metal.
- Cure it in a dry, dark space, with airflow. As dark and dry as you can. Not inside a locked cabinet or drawers, but a dark and dry enough space for it to be able to have circulating air, and stable temps.
If you need to cover them, depending on the surroundings, use gauze cloths or other thin and breathing cloth. Nothing thick, and no plastic.
If you don`t have a suitable dark space, you can use a cardboard box and punch a lot of holes so it can get enough air to circulate, and close the lid, to keep it dark enough. Don`t set it on the floor, set it on a table or on top of a cabinet or whatever is high to get it higher up.
If nothing of the aformentioned advice works I don`t really know what else to say. I will assume that you soap with well cleaned tools, but if you don`t clean the tools really well between uses, you may want to start now so that is not an issue if you want to try a new and fresh batch.
I hope you have found anyting i have said helpfull, and this is all I can think of. Others can perhaps have other insights and ideas.
Good luck