Months after curing soap turns yellow orange and smells bad

[foresthome]

I am not new to soaping. I have been making soap for over 9 years. I have a nice small successful soap business. In the last 7 months I have had 2 batches of soap that were around 6 months old change color to a yellow orange and smell awful. This has never happened before. One soap was scented with fragrance oil and oxide colorants, and the other was my unscented uncolored soap. My base recipe is Castor oil 9.68%, Coconut oil 32%, Olive oil 19.35%, Pomace Olive oil 19.35%, Rice Bran oil 19.35%. Any ideas. All my oils have been purchased in the last year, and none of them smell bad.

 

[Cellador]

It might still be DOS. Is it just spots on the soap or the whole bar? How have they been cured?

 

[foresthome]

It is the whole bar. It happened after curing 6 months in both cases. OO pomace and rice bran oils are a new addition as they were less expensive that pure OO. Started using them in the last 2 years. I get my oils from Soaper's Choice at Columbia Foods.

 

[Obsidian]

That definitely sounds like rancidity. It doesn't always show up as spots, in can form on the whole bar.

You might try switching back to your regular OO and see if that helps.

 

[shunt2011]

Its absolutely rancidity. I’ve had soap recently go rancid made with rice bran at about 6 months. I’ve never had it with regular OO or even a mix of OO and avocado.

 

[TheGecko]

All my oils have been purchased in the last year, and none of them smell bad.

As a side note, the clock on the “shelf life’ of an oil or butter is not the day you bought, but the day is was produced. You don’t know how long your oil or butter was sitting on the shelf or warehouse or the bottler or in the hold of a ship before your purchased it. I just assume that whatever I buy is only good for half the shelf life, not that I would know where I would store a year’s worth of Olive Oil. LOL

 

[foresthome]

I checked the dates on all my oils and none have expired, but will probably stop using rice bran oil. Almost all of my soaps have turned out fine except for these 2 batches. The bad thing is that it didn't turn for 5 or 6 months and were already on store shelves by that time. So I feel horrible that people bought a bad product from us. I am running around the 60 mile radius to all 7 stores that carry our soaps and pulling them all.

 

[Lin19687]

Don't be so quick to jump on the RBO, I have bars over a year old with it.
We would need to see a pic to be sure of the DOS. Usually it is small spots that start first.
How are your oils stored and what are the temperature swings in that area?

I would more blame the FO that you used if it is completely all over. How old was it, where did you buy it from, how did you store it. I had made 4 batches one day with different FO's, only 1 got DOS so it HAD to have been the FO, I pitched that bottle (and the soap)
Or the Pomace since that is the bottom of the barrel of OO's

EDIT since you just posted: If these are at a store WHERE are they located? I had Sun damage to one bar but not the others. May be that or may not be.

 

[DeeAnna]

"...We would need to see a pic to be sure of the DOS. Usually it is small spots that start first...."

Maybe it's not quite as common as spots of rancidity, but all-over rancidity is definitely an issue to keep in mind. I wouldn't call it DOS exactly, because it's not spots here and there from localized contamination.

Widespread all-over rancidity comes from some kind of widespread problem. The problem could be the use of rancid fats, a high % of polyunsaturated fatty acids that break down easier, very high superfat, water with dissolved metallic contaminants, colorants with a high % of metal content, oxidized fragrances (both EOs and FOs), exposure to UV light, exposure to ambient dust and general air pollution during storage, excessive heating, etc. Used soap bars that get left alone for some weeks or months can become all-over rancid from tap water and from contamination on dirty hands.

A few threads where these issues with rancidity are discussed --
https://www.soapmakingforum.com/threads/question-on-my-7-month-bastille-soap.58256/
https://www.soapmakingforum.com/threads/key-to-sf-swap-dont-look-if-youre-not-ready.45657/
https://www.soapmakingforum.com/threads/soapqueens-invigorating-shampoo-bar-recipe.45322/

 

[TheGecko]

I checked the dates on all my oils and none have expired, but will probably stop using rice bran oil. Almost all of my soaps have turned out fine except for these 2 batches.

When I was talking about dates, I checked a bottle of Avocado Oil that I bought a couple of weeks ago at the local grocery store to experiment with. According to the label it's 'good' until 02/25/21, so I double checked the shelf life for AO and it said 1 year so I went back to the label and it says 100% Cold Pressed Avocado Oil so 'what the heck karen'?!? Maybe someone with a whole lot more experience can help me out here.

I wouldn't be tossing out the RBO, I know several soapers who use it with no issue and as you noted, all your batches turned out fine except for two. So let's do some process of elimination:

1. Since the two bad batches were color/scented and uncolor/unscented, we can first eliminate the FO and oxide that you used.

2. Since you used the same recipe for all your soaps, let's look at your ingredients. Did you use the same ingredient lots for all your soaps or did you run out of something and had to open a new container? I had that happen with Castor Oil and Cocoa Butter on Friday; I didn't have enough of either to make a 2lb batch, so I set it aside and opened new containers. The other will either go into a 1lb batch or will go into 'house' soap. Once you open a container, it is subject to contamination even if it's just air...and the lower the amount, the more air. And unless your ingredients are stored in a controlled environment, they are subject to temperature and humidity variances. It could be that your bad soaps contained an older, contaminated ingredient.

3. If you used all the same material lots, next item is equipment. Most of the time I run my equipment through the dishwasher, but sometimes I don't. I can always tell if I don't get the container for my lye solution perfectly clean I get 'floaties' (usually soap residue since I don't have a dedicated container). And I try to make sure all my equipment is only used for soap making and everything is properly stored in drawers and cabinets after washing (I have a rolling kitchen island), but sometimes I fail in that. I'll leaving something in the drainboard for a few days or my daughter just sets my stuff on my 'island' when she empties the dishwasher. And because I hate wasting paper towels, I use dish towels and now have a set that I only use for soap making to wipe surfaces, equipment and my hands.

The bad thing is that it didn't turn for 5 or 6 months and were already on store shelves by that time. So I feel horrible that people bought a bad product from us. I am running around the 60 mile radius to all 7 stores that carry our soaps and pulling them all.

That is probably best.

 

[DeeAnna]

Frankly, rancidity is always going to be a problem. Even if you buy your fats direct from the producer, other issues can trigger rancidity as others are pointing out, whether it's overall rancidity or DOS.

Definitely do all you can to minimize the problem, but realize you can never entirely eliminate this risk no matter how careful you are. In the commercial soap making world, chelators and antioxidants are both used to protect against rancidity, but chelators are considered more effective overall than antioxidants. So if you only use one, consider adding a chelator.

 

[cerelife]

Just another opinion on RBO as the culprit. I've used it for over 7 years and so far I've never had any issues with DOS/rancidity.

 

[DeeAnna]

I've used RBO too, but generally only a relatively modest % of the total fat. I didn't see any huge problems with using RBO either, but it was not a big part of my recipe.

I suspect it's less about the particular fat used and more about the proportion of polyunsaturated fatty acids in the soap compared with monounsaturated and saturated fatty acids. The more PUFA, the higher the likelihood of rancidity.

 

[Quilter99755]

I've used RBO too, but generally only a relatively modest % of the total fat. I didn't see any huge problems with using RBO either, but it was not a big part of my recipe.

I suspect it's less about the particular fat used and more about the proportion of polyunsaturated fatty acids in the soap compared with monounsaturated and saturated fatty acids. The more PUFA, the higher the likelihood of rancidity.

I must have missed a lot in other discussions. What is a good proportion of PUFA to mono? I just looked at my past recipes and almost all are heavier on the PUFA's. But I have only had DOS in one of my soaps and that was one bar that my daughter had under her bathroom counter that slipped behind her soap container. We thought it might have been more that it got moisture or other things spilled on it rather than the recipe. We think it had been there at least 2 years, maybe more.

 

[DeeAnna]

My rule of thumb is to keep the total linoleic + linolenic below about 15%. My recent recipes are well under 10%. Now that's just a rule of thumb I've picked up over the years, and I have no scientific basis for it.

Some people look at the iodine number and keep that value below a certain level. The iodine number is a test for the amount of unsaturated fatty acids. I think Soapcalc suggests the iodine number should be something under 70.

The recipes I've been making lately are 55-58 for the iodine number and 5-7% combined linoleic + linolenic. One or the other rule of thumb is plenty good to worry about. You don't need to check both.

 

[Quilter99755]

Thanks DeeAnna. The gods must have pity on me as all my recipes have been within the range although on the high end. I'll have to go back and study some more. Sometimes this old brain just can't absorb all it should.

 

[CatahoulaBubble]

I would say it's the percentage of rice bran oil you used. I quit using it altogether because combined with my goat milk it just didn't hold up and would go rancid. But I could be wrong, I only experimented with adding RBO and didn't care for the results so I went back to my tried and true. I only make milk soap though.

 

[Jennifer Horne]

As a side note, the clock on the “shelf life’ of an oil or butter is not the day you bought, but the day is was produced. You don’t know how long your oil or butter was sitting on the shelf or warehouse or the bottler or in the hold of a ship before your purchased it. I just assume that whatever I buy is only good for half the shelf life, not that I would know where I would store a year’s worth of Olive Oil. LOL

When the oils smell like crayons they are not good..... so use them fast lol

 

[CatahoulaBubble]

If you worry about the shelf life of your oils you can store them in the freezer. I buy in bulk and then portion out my oils in smaller containers and store them in my deep freeze.

 

[foresthome]

My rule of thumb is to keep the total linoleic + linolenic below about 15%. My recent recipes are well under 10%. Now that's just a rule of thumb I've picked up over the years, and I have no scientific basis for it.

Some people look at the iodine number and keep that value below a certain level. The iodine number is a test for the amount of unsaturated fatty acids. I think Soapcalc suggests the iodine number should be something under 70.

The recipes I've been making lately are 55-58 for the iodine number and 5-7% combined linoleic + linolenic. One or the other rule of thumb is plenty good to worry about. You don't need to check both.

Yes my recipe is 9 % combined linoleic/linolenic, and iodine is 61. Since one of the soaps that turned was my unscented uncolored bar, I am thinking it is the addition of the RBO. Which is new in the last 18 months. I pulled soaps that were 8 years old, prior to the addition of RBO, and they have no DOS.