Weird (rancid) smell in LS?

[fuzz-juzz]

I'm using LS recipe by IrishLass and I'm generally happy with it. It's gentle on my hands, works great in foaming bottles etc.

However, I've been having some issues with it when it gets mixed with particular FOs. It gets this really weird, rancid smell to the point of being unusable.
I only mix enough FO/soap mixture just enough for one bottle at the time. Some FOs work great, while some make really vile smelling LS. It's evident pretty much straight away. It's not like it sits there for days. LS that remains in the big jar (without added FO) smells fine, just like plain LS
Did anyone come across something similar?

I know it's probably issue with certain FOs but I'm just curious. I only use BB and NG FOs.

 

[Susie]

Which FOs, in particular, are you having trouble with?

 

[DeeAnna]

While I have not noticed the weird/rancid/vile odor you describe, some FOs will have a bitter or sour tang to my nose when I use them in liquid soap. What's odd is sometimes these same FOs can be just fine in bar soap.

First thing I try is to back way down on the % of fragrance. Sometimes a dosage of 0.5% or less is plenty good.

In a few cases, I've decided I don't want to use the FO again in liquid soap. It's less that it smells vile and more that it isn't a scent I care for in LS. Cool Spring from NG is an example.

Not sure if this idea will be helpful for your problem, but FWIW....

 

[Misschief]

I've noticed the same thing, to the point that I almost never use my liquid soap. DH doesn't seem to notice, or care, but I sure do. It's an off-putting scent that doesn't quite smell rancid but just doesn't smell nice. It doesn't matter whether it's scented or not, it still smells kind of funky.

 

[Dahila]

I noticed the strange smell, and my son too, it was like amonia, and I think it was cooked glycerin, so I had switched to mixing KOH in one part of water then adding slowly glycerin, the soap smell fresh and nice without any fragrance. I use FO any of them except Monkey fart , Even with FO I do mix it with PL8o. Misschief maybe it is the same smell I noticed....

 

[Susie]

I've noticed the same thing, to the point that I almost never use my liquid soap. DH doesn't seem to notice, or care, but I sure do. It's an off-putting scent that doesn't quite smell rancid but just doesn't smell nice. It doesn't matter whether it's scented or not, it still smells kind of funky.

What recipe is it? And how many different recipes have you tried to find to get rid of that scent?

I am not challenging, just asking. Because I have a really sensitive nose, and I don't get that scent unless I am making LS with lard or tallow. And that is easily covered with the citrus EOs I use in LS.

 

[Misschief]

What recipe is it? And how many different recipes have you tried to find to get rid of that scent?

I am not challenging, just asking. Because I have a really sensitive nose, and I don't get that scent unless I am making LS with lard or tallow. And that is easily covered with the citrus EOs I use in LS.

I followed the recipe in the glycerin liquid soap thread: coconut, castor, olive. Since it was my first time making it, I didn't want to stray from IL did.

I've only made gls twice, once following the recipe and the second time making the "pearly" liquid soap. I still have some of each left which is why I haven't made any more. I've actually been trying to decide if I WILL make more because of the smell. I mean, it's lovely soap but I'm put off by the scent.

 

[Misschief]

I noticed the strange smell, and my son too, it was like amonia, and I think it was cooked glycerin, so I had switched to mixing KOH in one part of water then adding slowly glycerin, the soap smell fresh and nice without any fragrance. I use FO any of them except Monkey fart , Even with FO I do mix it with PL8o. Misschief maybe it is the same smell I noticed....

That could well be it, Dahila. Maybe I'll try it the way you do.

 

[Susie]

Add the glycerin to the oils. I HATE the smell of the "overheated" glycerin! Now I know what y'all are talking about! That is really the only time I let the KOH/water cool down while I weigh out my oils. I always soap hot otherwise.

 

[DeeAnna]

But if it's the smell of overheated glycerin, wouldn't that also make the unscented LS smell too? <...scratchin' my head...>

 

[Dahila]

DeeAnna I was asking about that smell, when I made the IL glycerin LS, last two times I added KOh to water and then slowly added the glycerine to KOH then without any waiting went to make a soap. I worked perfectly.
Susie I had done your way and (probably temps to high) my soap went to garbage, it left my pot thanks heaven it went on ceramic floor not on me. So I add it to hot KOH water) it works perfectly nice smell, no more ammonia smell

DeeAnna my unscented soap smelled like that the first time. I had to add a lot FO to mask it.

 

[fuzz-juzz]

Which FOs, in particular, are you having trouble with?

Some florals from BB like Lilac and Clean (type), Japanese cherry blossom, Orchid rain (this one is worst) from NG. There's more that I tried over the past year or two but can't remember.
There's some mixed with Beach daisies and it's perfectly fine. There is still that plain LS smell that I don't mind but the really off/rancid smell is horrid.

Thanks for input everyone. I might try next batch without heating just to see how it turns out. I'm almost out of this batch anyway.

 

[fuzz-juzz]

But if it's the smell of overheated glycerin, wouldn't that also make the unscented LS smell too? <...scratchin' my head...>

That's what puzzling me too!

I briefly cook my LS paste just until translucent (30mins or so). I know it's step away from IL recipe but LS I get is nice and with just a bit of plain soap smell.
This rancid smell that appears after adding FO kind of lingers on your skin and you can smell it let say in the bathroom for 10-15 mins after someone washed their hands. It's really that bad...

 

[Soapmaker145]

Some florals from BB like Lilac and Clean (type), Japanese cherry blossom, Orchid rain (this one is worst) from NG. There's more that I tried over the past year or two but can't remember.
There's some mixed with Beach daisies and it's perfectly fine. There is still that plain LS smell that I don't mind but the really off/rancid smell is horrid.

Thanks for input everyone. I might try next batch without heating just to see how it turns out. I'm almost out of this batch anyway.

In my testing of FOs (NaOH cp), I've noticed that some will cause DOS with time. They act like a catalyst. The cherry Blossom from BB is one of the worst. At about 8 or 9 months, my tester was pure solid DOS all the way through to the middle. I've never seen anything like it. Other florals had clear DOS spots on the surface and some discoloration or off smell inside. These soaps were poured in groups of 30 to 50. Only few, mostly florals had this problem. I would imagine liquid soap will turn a lot faster particularly with overheated glycerol. You probably have some reactive species ready to go as soon as you add the fragrance.

 

[Susie]

But if it's the smell of overheated glycerin, wouldn't that also make the unscented LS smell too? <...scratchin' my head...>

Frankly, if the glycerin causes the soap to be dark, I throw it away. I do not even try to dilute it. (And you know how much I hate to throw anything away!) That's exactly why I soap it cooler than I would any bar soap. I try not to overheat/burn that glycerin.

 

[DeeAnna]

One of the chemicals created when glycerin decomposes from being overheated is nasty smelling acrolein. Only a small amount of this hazardous chemical will create a distinct odor -- the human nose is very sensitive to it. The unpleasant smell and darker color in older or overheated deep-fryer fat is at least partly from tiny amounts of acrolein - the fat breaks down into fatty acids and glycerin and then the glycerin breaks down further.

 

[Dahila]

so it was not our imagination? My DH could not smell anything , but he is a heavy smoker
.

 

[Misschief]

But if it's the smell of overheated glycerin, wouldn't that also make the unscented LS smell too? <...scratchin' my head...>

Mine does. I generally leave my soaps unscented because I prefer them that way.

 

[fuzz-juzz]

In my testing of FOs (NaOH cp), I've noticed that some will cause DOS with time. They act like a catalyst. The cherry Blossom from BB is one of the worst. At about 8 or 9 months, my tester was pure solid DOS all the way through to the middle. I've never seen anything like it. Other florals had clear DOS spots on the surface and some discoloration or off smell inside. These soaps were poured in groups of 30 to 50. Only few, mostly florals had this problem. I would imagine liquid soap will turn a lot faster particularly with overheated glycerol. You probably have some reactive species ready to go as soon as you add the fragrance.

Thank you for this, it makes sense now.

I've collected lots of floral FOs in smaller sample bottles, most of them didn't turn out well in CP so I tried to use them up in LS. It's really interesting how they start to react with LS, literally within minutes. I tend to keep LS unscented until it's needed to be poured into foamers, I mix in FO and it's ready to be used.

My LS stays lovely yellowish colour (think pee colour lol), I only heat it up for 20-30 mins or so, it goes through gel really fast. I don't see point in cooking it for 3-4 hrs what some soapmakers do. By that time, it's really dark amber colour and now I know why. I never knew you can burn glycerin until this thread.

 

[Soapmaker145]

Thank you for this, it makes sense now.

I've collected lots of floral FOs in smaller sample bottles, most of them didn't turn out well in CP so I tried to use them up in LS. It's really interesting how they start to react with LS, literally within minutes. I tend to keep LS unscented until it's needed to be poured into foamers, I mix in FO and it's ready to be used.

My LS stays lovely yellowish colour (think pee colour lol), I only heat it up for 20-30 mins or so, it goes through gel really fast. I don't see point in cooking it for 3-4 hrs what some soapmakers do. By that time, it's really dark amber colour and now I know why. I never knew you can burn glycerin until this thread.

I think the problem is when you dissolve the KOH in heated glycerol as DeeAnna explained. I think most of the damage is done at that point (because the temperature is much higher) and not when you cook the soap. I've made few LS batches but I dissolve the lye in water. I add a little glycerol after I mix the oils and the lye. Once the batter is very thick, I leave it alone until I need it. When I'm ready to dilute, I have a nice jelly. I think IL modified her procedure to dissolve the KOH in a little water before mixing the glycerol. I think you'll have less problems with the modified method. I'm sure there is a ratio of water to glycerol that is optimal but I haven't had time to test.

Not all floral FOs create DOS problems/rancidity. The few from BB have been the only ones so far to misbehave in about 500 samples. I'm sure there is a single chemical common to all of them that created the problem. If you like florals, don't give up on them based on one negative experience.