(CP) How much should I worry about DOS and soaps going rancid?

[SoapHobbyJT]

How often/much do you need to worry about rancidity and DOS of oils and cold process soaps?

I've made my soaps with oils from WholesaleSuppliesPlus and ElementsBath&Body the oldest of these oils was purchased about 3 months ago. I have recently started adding EDTA as a chelating agent in my last 4 batches, included hydrogenated soy wax to increase the stearic acid for longevity, and I only use distilled water. However I make a lot of soap that I don't think I'll be gifting anytime soon because COVID and quarantining.

Plus, I'm not sure how clean I can get my mold that I reuse, as I can't help but still smell FO on some of my stuff from previous batches even after soaking them for a day and rinsing them out, then putting dish soap and vinegar in to let them soak and then pour out again for another day. I also have a batch of 100% olive oil soap as well and I don't want to hand those out before at least 6 months to a year of curing.

I do want to gift out a pretty decent amount of the soaps I've made in a couple of months, but if they start to smell funny or develop DOS I'm pretty sure all of those soaps will suddenly become personal use only. I am not looking forward to having to deal with a bunch of soap that's gone rancid and try to use them up on my own as well.

I'm actually suddenly worried a lot of my soaps will go rancid or develop DOS after I gift them out or don't use them up quickly now. How worried should I be of that?

Other than the addition of Tetrasodium EDTA, Sodium Citrate, and ROE, as well as purchasing oils from reputable sellers, what other ways are there to avoid/prevent DOS/soap rancidity for the long term (on a timescale of years if possible)?

 

[AliOop]

Coupla suggestions...

Don't worry about the FO smell in your molds. Somehow, it doesn't transfer to new soaps. It's like the FO highway only goes one direction - only into the molds, not out of the molds.

You may still want to deodorize them at some point for the sake of your own nose. My best deodorizing results were putting the molds in a 350F oven for 10-20 minutes. The molds came out with zero smell. Unfortunately, then my oven smelled like FO for months, and it did transfer to the food. The next time I need to do this, I'm either going to try hanging them over a hot BBQ grill, or getting a small, cheap, soaping-only microwave that I can keep in the garage, where the smell won't bother me.

If you are using distlled water, fresh oils and ROE, and you are keeping your combined linoleic and linolenic number at 18 or under, and you are storing the soaps in a relatively dry, dark area, not in contact with metal, then you are unlikely to have your soaps go rancid.

However, you can avoid worrying about rancidity by gifting much of your excess cured soap to a local homeless shelter or other non-profit. Most of them are delighted to receive soap donations, and will go through them very quickly.

 

[SoapHobbyJT]

Coupla suggestions...

Don't worry about the FO smell in your molds. Somehow, it doesn't transfer to new soaps. It's like the FO highway only goes one direction - only into the molds, not out of the molds.

You may still want to deodorize them at some point for the sake of your own nose. My best deodorizing results were putting the molds in a 350F oven for 10-20 minutes. The molds came out with zero smell. Unfortunately, then my oven smelled like FO for months, and it did transfer to the food. The next time I need to do this, I'm either going to try hanging them over a hot BBQ grill, or getting a small, cheap, soaping-only microwave that I can keep in the garage, where the smell won't bother me.

Currently the oven smells strongly of peppermint.

Oh, so the way to deal with that is to basically cause it to reach the flash point of the FO so it'll basically evaporate and burn off? How would I do that with say a Polypropylene container I mix my soap in before pouring? Microwave it?

If you are using distilled water, fresh oils and ROE, and you are keeping your combined linoleic and linolenic number at 18 or under, and you are storing the soaps in a relatively dry, dark area, not in contact with metal, then you are unlikely to have your soaps go rancid.

I actually haven't added in ROE yet, since that one was a relatively new discovery and uh... I'm trying not to go too crazy with ordering soap-making stuff at this point in time. I have added it to a cart and may purchase it next time I need to purchase some lye or so in a couple months (maybe sooner if I run out of some oil or another), but do you think I should just go ahead and order it now then? Or wait for the next time I make another soap-making supply purchase?

As for metal... uh, is stainless steel alright? Would it be better if I put a layer of freezer paper between my soaps and the stainless steel drying rack they're on right now?

Linoleic and Linoleic fatty acids increase chance of DOS/rancidity?

As for dark area, not so much, they definitely do not get direct sunlight but they might get some indirect light from the north-facing window (in Northern Hemisphere) about 6ft (~2m) away and a bit over 3ft (~1m) up? and also from whatever other light makes it from my desk to its spot. I suppose I should try storing them in my closet then? (Guess I'm going to have very fragrant clothing )

However, you can avoid worrying about rancidity by gifting much of your excess cured soap to a local homeless shelter or other non-profit. Most of them are delighted to receive soap donations, and will go through them very quickly.

I never thought of that, that's a great idea, thanks! Uh, but if it's a rancid soap, or one that has some DOS, would you still recommend that path if it comes to it? Or just stick with personal use at that point?

Thank you for the suggestions! They're very helpful!

 

[AliOop]

Oh, so the way to deal with that is to basically cause it to reach the flash point of the FO so it'll basically evaporate and burn off? How would I do that with say a Polypropylene container I mix my soap in before pouring? Microwave it?

Sorry to hear about your minty oven but at least it is a food-type scent and not perfume-y. I don't think this method has to do with flashpoint as much as the heat causes the scent to release. The microwave is supposed to work for silicone smell-release, but I don't have experience with polypropylene. If you give it a try, please report back!

I actually haven't added in ROE yet, since that one was a relatively new discovery and uh... I'm trying not to go too crazy with ordering soap-making stuff at this point in time.

I think it is fine to wait until you make your next purchase.

As for metal... uh, is stainless steel alright? Would it be better if I put a layer of freezer paper between my soaps and the stainless steel drying rack they're on right now?

Yes, definitely put a layer of paper or plastic between the soap and any stainless curing surfaces. Often what is called "stainless steel" is just a cheap coating that is easily cracked or chipped. That exposes the soaps to the underlying metal, and causes them to get DOS.

Linoleic and Linoleic fatty acids increase chance of DOS/rancidity?

Yes. You might want to research some threads on here about that.

As for dark area, not so much, they definitely do not get direct sunlight but they might get some indirect light from the north-facing window

If possible, keep it away from even indirect sunlight. Shoe boxes with holes, or a curtain around your rack, can help with this.

but if it's a rancid soap, or one that has some DOS, would you still recommend that path if it comes to it? Or just stick with personal use at that point?

I definitely don't recommend donating rancid soap! I was only recommending that if you are concerned that it won't get used for a long time, that you donate it so that it does get used while it is still good. But honestly, I have soaps that are several years old and still good. But I do store them in dry, dark conditions.

 

[SoapHobbyJT]

Sorry to hear about your minty oven but at least it is a food-type scent and not perfume-y. I don't think this method has to do with flashpoint as much as the heat causes the scent to release. The microwave is supposed to work for silicone smell-release, but I don't have experience with polypropylene. If you give it a try, please report back!

That's true, this time it was peppermint, previously it was just a bunch of unscented soaps, and before that it was flowers (scent) in the oven

As for the not-flashpoint thing, that makes more sense in hindsight. Actually, nevermind, I won't even try to "science" it at all, as I just came to the realization, I have no idea how flashpoints and burn off would affect the actual scent. I assumed that if it went above the flashpoint or so it would burn off and disappear, but in hindsight I don't actually know that sort of information as I haven't looked into it anytime recently. Does it burn off into nothing? Turn into bits of soot and ash? Just acquire a strange or burnt smell? Weaken? Unknown to me at this point in time (into my random research bucket list it goes).

I will definitely let you know if the heat it up in the microwave thing works for polypropylene items!

I think it is fine to wait until you make your next purchase.

[...]

Yes, definitely put a layer of paper or plastic between the soap and any stainless curing surfaces. Often what is called "stainless steel" is just a cheap coating that is easily cracked or chipped. That exposes the soaps to the underlying metal, and causes them to get DOS.

[...]

If possible, keep it away from even indirect sunlight. Shoe boxes with holes, or a curtain around your rack, can help with this.

Aye aye, Cap'n! o7

On the double!

Might be high time to actually start wrapping soaps up in wrapping paper to prevent stuff from getting to them as well.

Actually, before I run off and do that, would you recommend doing that? Reasons against would include things like: not being able to easily check soap for DOS/rancidity, potentially not allowing the soap bars to cure as well due to breathability (admittedly I was only thinking of wrapping the bars that have stopped changing weight for 2 weeks in a row now and it's not like the wrapping paper is even close to water proof), potential more things I haven't thought of just yet.

Yes. You might want to research some threads on here about that.

Yet another thing to go into my research bucket. Along with a look at rancid soaps vs DOS. It has just occurred to me that they may be 2 different things.

I definitely don't recommend donating rancid soap! I was only recommending that if you are concerned that it won't get used for a long time, that you donate it so that it does get used while it is still good. But honestly, I have soaps that are several years old and still good. But I do store them in dry, dark conditions.

Thanks! That reaction made me realize I needed to take another good look at what rancidity was. Somehow I thought it was still kinda maybe sorta good to use at that point. However, I think that was more along the lines of, if DOS is just in a few spots, the soap doesn't feel or smell funny, and you cut those spots out, then go ahead and keep using it rather than, just straight up use it.

Oops. I swear I have a brain somewhere in here.

Also, isn't this the exact reason I was worried about rancidity? Oh. Yeah, guess I have the rumored 3 second memory of a goldfish too.

I swear I have memory somewhere in here!

Thanks so much for the help!

 

[AliOop]

No wrapping till they are cured. But there are ways to block light without wrapping them that still allow for air flow: curtains over or around the rack, closing the curtains on the window in the room... Whatever works for your curing situation is what you should do. I keep mine in a guest room that gets little use, and I rarely open the curtains.

 

[SoapHobbyJT]

No wrapping till they are cured. But there are ways to block light without wrapping them that still allow for air flow: curtains over or around the rack, closing the curtains on the window in the room... Whatever works for your curing situation is what you should do. I keep mine in a guest room that gets little use, and I rarely open the curtains.

I have a cunning scheme.

Closets are magic!

Pretty sure I have a nice open space in my closet, on a pretty sturdy box somewhere. Can't see how this could possibly go wrong

Unfortunately, I have a ton of little plants on my window sill, so closing my curtains hasn't been an option for months, at least I'm on the second floor rather than the first. I get some privacy as long as I don't get too close to the window

 

[KiwiMoose]

I have been making soap for over two years now, and I still have one bar from the first batch which is not rancid - but has lost its fragrance.
I've had two batches go rancid in my soap-making time - both within a month to two of making them. To this day I have no idea how this happened. I used my standard recipe, and the same oils that were used for the other batches, the same storage conditions, etc. Maybe the fragrance oil was off? I don't know. One thing I do know is that you probably won't want to use it personally - it's yucky!
So to answer your question, I don't think you should worry at all. Just follow the guidelines that others have mentioned to be on the safe side ( non-metal storage, low linoleic etc) and be worry-free!