One bar went rancid?!

[Zing]

Smart soap peeps,
I spent the weekend with Sis. She had a bar of my Spring Clean from my batch I made in May. It was rancid! It's my most popular bar both purchased and gifted and a recipe I've made for over 3 years. My same standard recipe. I store cured soaps in shoe boxes lined with paper towels. Her house is a refrigerator in the summer with air conditioning set to freezing. This is the Sis who normally likes to use my soaps as decoration but this bar was in active use on the bathroom sink in a room without windows. All the bars I still have in storage are fine. I store all my butters and oils in the refrigator and pull them out 24 hours before a soaping session. Any guesses?

 

[MellonFriend]

Was the bar stored in your sister's house with other soaps that had gone rancid? That's my very uneducated guess. Maybe the rancidity spread?

 

[TheGecko]

This is the Sis who normally likes to use my soaps as decoration but this bar was in active use on the bathroom sink in a room without windows.

Was it on anything while it was on the bathroom sink?

 

[AliOop]

Does the soap dish have any metal on it, even metallic paint?

 

[KiwiMoose]

Aww no! If your ones at home are ok, it must surely be something to do with her place that has caused it. I bet she didn't even notice, lol. My mum was using a rancid one of mine and didn't notice.

 

[Zing]

@AliOop may be on to something - I have a message out to Sis. Right now I can't visualize that particular sink and soap dish. I do know in that bath that she likes to display my soaps on an antique washboard made of wood and metal. However, I do know that the guest bath does have a metal soap dish! Clearly I need to do an inspection to maintain a safe and welcoming environment for soap!

And @KiwiMoose , she clearly didn't know anything was wrong -- but it for dam sure didn't smell like lemongrass/rosemary!! My dad used a rancid soap for weeks til I couldn't take it anymore and tossed it. And his vanity drawer was stuffed with years of my gifts and the crayon smell nearly knocked me out.

 

[Ugeauxgirl]

I read somewhere that infrequently used soaps are more likely to go rancid than properly stored soaps. It was that bubble test I read awhile back. I'll see if I can find it

 

[Ugeauxgirl]

Here it is

https://www.modernsoapmaking.com/blog/updated-lather-lovers-additive-testing